v o l u m e 2 9 j u n e 2 0 0 0

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0

http://slidepdf.com/reader/full/v-o-l-u-m-e-2-9-j-u-n-e-2-0-0-0 1/32

M e c h a n i c a l

E n g i n e e r i n g

N e w s

FOR THE POWER,

PETROCHEMICAL AND

RELATED INDUSTRIES

The COADE Mechanical Engineering

News Bulletin is published twice a yearfrom the COADE offices in Houston,Texas. The Bulletin is intended to provideinformation about software applicationsand development for MechanicalEngineers serving the power, petrochemi-cal and related industries. Additionally, theBulletin serves as the official notificationvehicle for software errors discovered inthose Mechanical Engineering programsoffered by COADE.

©2000 COADE, Inc. All rights reserved.

V O L U M E 2 9 J U N E 2 0 0 0

What’s New at COADETANK Version 2.10 Released ........................ 1PVElite Version 4.00 New Features ............... 2PVElite 4.00 and CodeCalc 6.30 New Feature:

Finite Element Analysis Interface. ............. 4Using the Full Potential of the COADEWebsite ...................................................... 6

Technology You Can UseCAESAR II Version 4.20 Introduces New 3D

Interactive Graphics ................................... 8Using CAESAR II ODBC Data Export .......... 11Upgrading Databases from Access 97 to

Access 2000 ............................................ 14Modeling Widely Spaced and Closely Spaced

Miter Bends in CAESAR II ....................... 16Beam Element Models and the ASME B31

Codes ...................................................... 19Undocumented CAESAR II Gems ............... 23WRC 107: Elastic Analysis vs. Fatigue

Analysis ................................................... 24PC Hardware for the Engineering User

(Part 29) ................................................... 29

Program SpecificationsCAESAR II Notices ...................................... 31TANK Notices ............................................... 31CodeCalc Notices ........................................ 32PVElite Notices ............................................ 32

Finite ElementAnalysisOptions inVessel Software> see story page 4

Pitfalls ofComputerizedAnalysis

> see story page 19

Mitered Bends

and other Gems> see stories onpages 16 and 23

Secrets of the"Windows" Keys> see story page 29

TANK Version 2.10 Released(by: Richard Ay)

TANK Version 2.10 was released in May of 2000. Version 2.10 updates thesoftware to comply with the latest editions and addenda of API-650 and API-653. Version 2.10 also incorporates venting computations as per API-2000.The dialog for the venting input data is shown in the figure below.

I N T H I S I S S U E :

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0


COADE Mechanical Engineering News June 2000

2

One of the most important improvements to the software is amodification to the allowable stress input dialog.

This dialog has been expanded to overcome a misconception manyusers have regarding the specification of stainless steel data. Forstainless steels, API-650 provides a table of allowable stresses, as a

function of temperature. The actual allowable stress used duringthe computations is not known until run-time, when the softwareinterpolates the API-provided table. Since the actual allowable isunknown at the time of input, the data column for Sd is shown as0.00. The presence of this zero value has alarmed many users, whohave subsequently attempted to specify the allowable stress, resultingin improper behavior of the software.

For Version 2.10, this allowable stress input dialog has beenexpanded to include the entire allowable stress versus temperaturetable for any shell course constructed of stainless steel. Thisexpanded dialog is shown in the figure below.

Note that the data column for Sd is still shown as 0.00. This isbecause the actual allowable stress is still unknown, until run-time.The added allowable stress data (in the columns labeled “SSD1”through “SSD5”) will hopefully make the intent of the input clearer,and avoid future problems with the specification of stainless steels.

PVElite Version 4.00 New Features(by: Scott Mayeux)

PVElite version 4.00 represents the latest advancements in COADE’spressure vessel design and analysis software. This version containsseveral new and exciting features. The major features are:

• 3D model viewer

• BS–5500 Appendix G local stress evaluation for round hollow

nozzles on spheres and cylindrical shells• DXF file generation

3D Viewer

This viewer is a stand-alone application that can read any PVEliteinput file and render it. Some of the functionality includes real timemodel rotation, zooming, panning, cutting planes, wire frameviewing, tool tips and many others. The modeler makes many

problems, such as component interference, much more noticeable.The following example problem model was rendered and cut usinga cutting plane.

BS-5500 Appendix G Calculations

Another major feature is the addition of BS-5500 Appendix Gcalculations. This is essentially the British version of WRC 107/ 297 but with some exceptions. One main difference is that this localstress calculation is a part of the British pressure vessel code,whereas WRC 107 and 297 are not part of ASME Codes Section

VIII Divisions 1 or 2. Another difference is that Appendix Gprovides allowable stresses, whereas the WRC versions are notspecific in this area.

The input for Appendix G calculations is nearly identical to 107 or297. Specify the loads, dimensional information and other data.Then make the run. A sample BS-5500 problem is shown below.

Input Echo, Appendix G Item 1, Description: BS NozzleCalc.

Diameter Basis for Vessel Vbasis OD Corrosion Allowance for Vessel Cas 0.0000 mm. Vessel Diameter Dv 2540.000 mm. Vessel Thickness Tv 23.000 mm. Vessel Shell Design Allowable Stress f 150.000 N/mm²

Vessel Shell Yield Strength fy 227.000 N/mm² Allowable Stress Intensity Factor (Mem + Bend) 2.25 Allowable Stress Intensity Factor (Membrane) 1.20

Diameter Basis for Nozzle Nbasis OD Corrosion Allowance for Nozzle Can 0.0000 mm. Nozzle Diameter Dn 219.000 mm. Nozzle Thickness Tn 15.200 mm. Nozzle Inside Projection h 0.000 mm.

Stiffened Length of Vessel Section L 3000.00 mm. Offset from Left Tangent Line Dx 1500.00 mm.

Design Internal Pressure Dp 1.10 N/mm² Radial Load Fr 4410.00 N

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0


June 2000 COADE Mechanical Engineering News

3

Circumferential Shear Fc 6600.00 N Longitudinal Shear Fl 6600.00 N Torsional Moment Mt 8900000.00 N•mm Circumferential Moment Mc 3630000.00 N•mm Longitudinal Moment Ml 3630000.00 N•mm

Stress Calculations at the Edge of the Nozzle Neck :==================================================

Mean nozzle diameter / Mean Shell Diameter d/D: 0.0810

Compute the value of Rho: rho = d/D * sqrt( D / ( 2 * ( ers - Cas ) ) ) rho = 203.80/ 2517.00 * sqrt( 2517.00 / ( 2 * ( 23.00 - 0.00 ))) rho = 0.60

The following are the curves of rho selected for the analysis: Values of Rho: 0.500 (Curve1), 0.599 (Computed rho), 0.600 (Curve2)

Values of erb/ers for values of rho: 0.430, 0.540, 0.520, 0.660

Intermediat e Values L o n g i t u d i n a l Circ. Radial At Point A Point B At C

———————————————————————————————————————————————————————————————————————— K Factor K 8.0000 8.0000 2.0348 Load over the Area W 31432.2 -31432.2 31432.2 -4410.0 Equivalent Length Le 2995.5542 2995.5542 3000.0000 3000.0000 Parameter Cx 28.8717 28.8717 86.6150 86.6150 Parameter Cø 86.6150 86.6150 28.8717 86.6150 Parameter 64r(Cx/r) 1.8431 1.8431 16.5877 16.5877 Parameter 2Cx/Le 0.0193 0.0193 0.0577 0.0577

Parameter Cø/Cx 3.0000 3.0000 0.3333 1.0000

G6 Curve Value 0.1645 0.1645 0.1953 G7 Curve Value 0.1557 0.1557 0.1243 G8 Curve Value -0.1952 -0.1952 -0.1673 G9 Curve Value -0.1548 -0.1548 -0.1579

G6 at Zero 0.3364 0.3364 G7 at Zero 0.2439 0.2439 G8 at Zero -0.2064 -0.2064 G9 at Zero -0.1685 -0.1685

Circ. value Mø 0.4890 0.4890 Long. value Mx 0.6385 0.6385 Circ. value Nø 0.9461 0.9461 Long. value Nx 0.9188 0.9188

Curve Value Mø3/W 0.1245 0.1245 Curve Value Mx3/W 0.0489 0.0489 Curve Value Nø3/W -0.0684 -0.0684 Curve Value Nx3/W -0.1131 -0.1131

Value Mø2/W 0.0609 0.0609 Value Mx2/W 0.0312 0.0312 Value Nø2/W -0.0647 -0.0647 Value Nx2/W -0.1039 -0.1039

Circ. value Mø/W 0.1036 0.1036 0.1953 0.1389 Long. value Mx/W 0.1245 0.1245 0.1243 0.1013 Circ. value Nøt/W -0.1306 -0.1306 -0.1673 -0.1624 Long. value Nxt/W -0.0509 -0.0509 -0.1579 -0.1534

Pressure Stress SIF 2.0455

BS-5500 Appendix G Nozzle to Cylinder Stress Evaluation ———————————————————————————————————————————————————————

Quadrant Q1 Q2 Q3 Q4 Surface In Out In Out In Out In Out

Circumferential Stresses: Membrane Component (Nø/t) due to: Radial Load 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4

Circ. Moment -9.9 -9.9 -9.9 -9.9 9.9 9.9 9.9 9.9 Long. Moment -7.8 -7.8 7.8 7.8 7.8 7.8 -7.8 -7.8 Sub-Total loc. -16.3 -16.3 -0.8 -0.8 19.1 19.1 3.5 3.5 Pressure (fp) 123.1 123.1 123.1 123.1 123.1 123.1 123.1 123.1 Sub-Total(føm) 106.8 106.8 122.3 122.3 142.2 142.2 126.7 126.7

Bending Component (6Mø/t²) due to: Radial Load -6.9 6.9 -6.9 6.9 -6.9 6.9 -6.9 6.9 Circ. Moment 69.6 -69.6 69.6 -69.6 -69.6 69.6 -69.6 69.6 Long. Moment 36.9 -36.9 -36.9 36.9 -36.9 36.9 36.9 -36.9 Sub-Total(føb) 99.6 -99.6 25.7 -25.7 -113.5 113.5 -39.6 39.6

———————————————————————————————————————————————————————————————————————— Tot. Circ. Str 206.4 7.2 148.0 96.6 28.7 255.7 87.0 166.3

Longitudinal Stresses: Membrane Component (Nx/t) due to: Radial Load 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 Circ. Moment -9.4 -9.4 -9.4 -9.4 9.4 9.4 9.4 9.4 Long. Moment -3.0 -3.0 3.0 3.0 3.0 3.0 -3.0 -3.0 Sub-Total loc. -11.1 -11.1 -5.1 -5.1 13.7 13.7 7.6 7.6 Pressure (fp) 123.1 123.1 123.1 123.1 123.1 123.1 123.1 123.1 Sub-Total(fxm) 112.0 112.0 118.0 118.0 136.8 136.8 130.7 130.7

Bending Component (6Mx/t²) due to: Radial Load -5.1 5.1 -5.1 5.1 -5.1 5.1 -5.1 5.1 Circ. Moment 44.3 -44.3 44.3 -44.3 -44.3 44.3 -44.3 44.3 Long. Moment 44.4 -44.4 -44.4 44.4 -44.4 44.4 44.4 -44.4 Sub-Total(fxb) 83.6 -83.6 -5.2 5.2 -93.8 93.8 -5.0 5.0 ———————————————————————————————————————————————————————— Tot. Long. fx 195.6 28.4 112.9 123.2 43.0 230.6 125.8 135.7

Shear Stresses due to: Torsion Moment 5.1 5.1 5.1 5.1 5.1 5.1 5.1 5.1 Circ. Shear 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 Long. Shear 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8

———————————————————————————————————————————————————————— Tot. Shear tau 6.8 6.8 6.8 6.8 6.8 6.8 6.8 6.8

Check of Total Stress Intensity (membrane + bending) f1 Principle 209.7 30.3 149.3 124.8 45.7 257.4 126.9 167.7 f2 Principle 192.3 5.2 111.6 94.9 25.9 228.8 85.9 134.3 f2-f1 -17.4 -25.2 -37.7 -29.9 -19.8 -28.6 -41.1 -33.4

Check of Buckling Stress (only if Row 4, 15 in Compression) Row 4 + Row 10 83.3 -116.0 24.9 -26.5 0.0 0.0 0.0 0.0 Row15 + Row 21 72.5 -94.8 -10.2 0.1 0.0 0.0 0.0 0.0

Check the Maximum Stresses versus defined Allowables:

————————————————————————————————————————————————————— Maximum Stress Intensity (Membrane + Bending) : 257.40 Allowable: 337.50 Maximum Compressive Stress : -115.96 Allowable: -204.00 Maximum Membrane Stress : 146.80 Allowable: 180.00

PVElite DXF File Interface

Another new feature of version 4.00 is the DXF file generationoption. A DXF file is simply a text file in a very specific format.This type of file is referred to as a Data Interchange File and can beread by many programs including AutoCad, Intergraph and a hostof others to produce a drawing. The DXF file that PVElite producescontains dimensional information that the user has entered duringmodel creation. This option is useful for those who are creatingdrawings for fabrication or just to see what a vessel looks like forbidding purposes.

To get PVElite to create such a file, fill in the data in the DXFoptions tab as shown in the following figure. When the programruns, up to 3 DXF files will be produced. The files contain thedrawing itself, the nozzle schedule and the bill of material. Thenozzle and the bill of material are optional. With the exception of the scale factor, the other settings are saved in between sessions sothat they do not have to be checked repeatedly.

After the DXF files have been created, PVElite can invoke any

program available on the system capable of displaying a DXF file.This is simply done by pressing a button on the toolbar after the fileshave been created. Some companies have free DXF file viewersthat allow a file to be viewed and printed but not edited.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



4

In addition to this basic capability, PVElite version 4.00 alsoincludes many vessel drawing blocks, like welding symbols andothers, that accompany our CADWorx/Pipe program.

Version 4.00 of PVElite is scheduled for release in August 2000.

PVElite 4.00 and CodeCalc 6.30New Feature: Finite ElementAnalysis Interface

(by: Mandeep Singh

PVElite Version 4.00 and CodeCalc 6.30 will introduce an interfacefor gathering data to perform a finite element analysis (FEA) of nozzle-to-shell junctions. This analysis uses an encapsulated finiteelement program available from Paulin Research Group(www.paulin.com). This interface will be available within theWRC 107 module of PVElite and CodeCalc .

When it is necessary to determine shell stresses at the edge of anattachment (like a pipe nozzle-to- vessel intersection) due to externalloads, engineers will turn to Welding Research Council Bulletin107. However, there are times when the applicability of thisbulletin is in question or a particular design is out of the scope of thebulletin. A typical example might be a large nozzle. When thenozzle diameter divided by the shell diameter is greater than 0.33,many of the curves in WRC 107 may need to be extrapolated.Doing so may lead to non-conservative results. In this case andothers, FEA is the best way to get accurate results. Other exampleswhere an FEA can be useful are vessel types not addressed by WRC107, including those with reinforcing pads and Hillside and Lateralnozzles.

FEA is a powerful tool when used correctly. Users should have anunderstanding of the method and the experience to build the rightfinite element model. Along with the time constraints, engineerssometimes find it challenging to exploit the full benefits of FEA.The FEA “Black Box ” eases these concerns by providing relativelyeasy input, automatic meshing, and the results for code stress checksalong with other finite element results.

To run an FEA on the nozzle-to-shell (or head) junction in PVElitusers will select the WRC 107 module and set the analysis type asFEA. Next, the nozzle geometry information is entered. Nozzlescan be integrally reinforced or pad-reinforced and can be of theinsert or abutting type. A typical dialog is shown in Fig. 1.

Volume25

COADE Software Supports USB Port

No Parallel Port?Need a USB ESL?Let us know when you order your software.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



5

Figure 1: A snapshot of CodeCalc showing the Design tab andthe nozzle details dialog.

The information in the vessel tab contains the vessel type. Theavailable vessel types are conical, cylindrical, elliptical, flat,hemispherical and torispherical. Depending upon the type of thevessel specified, additional data will be required to complete theinput for the shell or head. Finally, under the loads tab, loadingvalues as well as the vessel and nozzle orientation are entered(Fig. 2).

Figure 2: The Vessel-Nozzle orientation dialog.

This example depicts an elliptical head in the vertical direction.Thus the direction cosines are (0, 1, 0). The nozzle is also in thevertical direction and is offset from the vessel centerline by 10inches. The nozzle direction is specified from the nozzle centerlinegoing into the vessel so the direction cosines are (0, -1, 0). Thenozzle orientation reference vector defines the reference axis from

where the orientation of the nozzle can be measured by the nozzleorientation angle. For example, if nozzle orientation reference axisis along x-axis and nozzle orientation angle is zero then the nozzleis located along the x-axis as seen in Fig. 3.

Three types of loadings can be entered: sustained, operating andoccasional. Operating and occasional loads are used for performingthe fatigue analysis. The next input is the miscellaneous informationfor the FE model. This completes the input needed for performingthe FEA. Fig. 3 depicts the finite element discretization and a stresscontour.

Figure 3: The Finite Element Mesh and the Primary MembraneStress contour.

The FEA program generates graphical results showing variousstresses. The most important results are shown below:

1. ASME overstressed areas are reported. A sample printout isshown here.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



6

ASME Overstressed Areas

Pad Edge Weld for Nozzle 1

Pl 1.5(k)Smh Primary Membrane Load Case 220,116 18,000 Plot Reference:

psi psi 1) Pl < 1.5(k)Smh (SUS,Membrane) Case 2

111%

2. The next report is the Highest Primary Stress Report. Itoutlines the stresses at critical locations such as the nozzle-to-shell junction and the edge of the pad.

3. Highest Secondary and Fatigue Stress Reports are alsoprovided.

4. Next, the program lists nozzle stress intensification factors foruse in a beam-type pipe stress analysis program such asCAESAR II .

5. The FEA program computes the maximum individual allowable

loads and simultaneously acting allowable loads. Both primaryand secondary loads are reported. A typical report is listedhere.

Allowable Loads

SECONDARY Maximum Conservative Realistic Load Type (Range): Individual Simultaneous Simultaneous Occurring Occurring Occurring Axial Force (lb. ) 398030. 120631. 180946. Inplane Moment (in. lb.) 5306513. 1137199. 2412363. Outplane Moment (in. lb.) 3358105. 719650. 1526608. Torsional Moment (in. lb.) 2343568. 710264. 1065396. Pressure (psi ) 344. 111. 111.

PRIMARY Maximum Conservative Realistic Load Type: Individual Simultaneous Simultaneous Occurring Occurring Occurring Axial Force (lb. ) 618455. 178300. 267450.

Inplane Moment (in. lb.) 5998639. 1222872. 2594104. Outplane Moment (in. lb.) 5458219. 1182725. 2508939. Torsional Moment (in. lb.) 2938301. 847110. 1270665. Pressure (psi ) 422. 111. 111.

The conservative simultaneous loads will produce stressesthat are approximately 60 to 70% of the allowable. Therealistic allowable simultaneous loads are the maximum loadsthat can be applied simultaneously; they produce stresses thatare closer to 100% of the allowable. The maximum individualoccurring primary pressure can be taken as a finite elementcalculation of the MAWP for the nozzle.

6. Nozzle-Shell junction flexibilities are also available. Theseflexibilities can be used to accurately model the flexibility of the junction and can be included in the pipe stress program thatis used to model the piping system attached to the nozzle.

In PVElite , users will have a choice of performing either a WRC107 or a finite element analysis from within the same module,without redundant input. As with any finite element program, usersshould visually check the finite element mesh for errors and makesure the FEA results make sense from the stress analysis perspective.

Using the Full Potential of theCOADE Website

(by: Richard A

The purpose of the COADE website is to provide information to

users and potential users of COADE software products. The websiteis, in essence, another support vehicle to which COADE devotes asubstantial amount of resources. The COADE website should beconsidered a primary means of staying in contact with COADE,especially if you are several time zones away from our home officein Houston, Texas. This article explores the many avenues throughwhich information can be obtained from the website.

The COADE website has been designed to provide useful informationin a timely manner. There is virtually no “fluff, ” “hype, ” or oth“baggage ” on this site. We don ’t have the time to spend on this, nordo our users have the time to waste on worthless information.

Most of the site can be accessed via the navigation bar on the left of the Home Page , shown in the figure below. The major topics of thisnavigation bar are discussed in the paragraphs below. In the upperright of the Home Page is a scrolling news banner. This sectionscrolls current news and software release information. Below this isa short list of items of greatest importance to users of COADEsoftware products.

In the top frame are several other important links. The “Site Maplink produces a concise, single page view of the entire website. The“Search ” link provides a search form from which the entire websitecan be scanned for a particular topic. The “Contact Us ” liproduces a page detailing complete contact information for COADE,as well as e-mail addresses of all COADE employees.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



7

What’s New:

This section of the website provides two quick ways to obtain thelatest COADE information. The first link in this section produces a“news ” file, which lists the latest developments at COADE. Thesecond link produces a “website revision history. ” A quick perusal

of this page shows immediately whether or not you need to look elsewhere on the site for new or updated information. This pagetypically includes direct links to the referenced subjects, for quick access.

(At the bottom of each page is the “last modified ” date of thepage. Use this to determine how up-to-date the page is.)

Company Information:

Probably the two most useful pages in this section are the “Travel ”and “Privacy Policy ” pages. The “Travel ” page can be used to

acquire (COADE) area maps, local weather, area hotels, and drivingdirections from the airport. This page also contains links to airlineand car rental sites. If you plan to attend a COADE seminar inHouston, this page is invaluable.

Internet privacy is a key area of concern to most businesses andindividuals. The “COADE Privacy Policy ” details exactly whatCOADE does with any information acquired from website visitors.In short, any personal information obtained from the website is usedsolely for COADE ’s marketing and support efforts. This informationis not revealed to third parties.

Products:

The “Product Details ” page of this section contains links to each“Product Description ” page of each of COADE ’s software programs.These pages contain detailed program descriptions, update histories,and links for demo downloads. At the bottom of the “ProductDetails ” page are additional links to pages describing the softwareupdate policy and the latest versions of all products.

The “Seminars and Shows ” page contains information on COADEseminars held in the COADE home office, as well as worldwideseminars hosted through our international dealer network. The“Shows ” section of this page lists the upcoming shows andconferences at which COADE ’s products will be exhibited.

Support:

The Support section of the navigation bar is the most important, andmost frequently used. The “Downloads ” page of this sectionproduces a list of COADE software products, from which users canview a list of files available for download. These files range fromexamples to software updates. This section should be checkedfrequently to ensure the latest edition of the software is in use.

( Note: Users who have registered their software via e-mail arenotified directly when an update is posted on our website .)

The download area also contains other useful files, such as the latestESL drivers, units conversion and other utilities.

The “Discussion Forum ” link takes you to the "Summary" page of the online discussion forums. These forums allow users to interactwith each other (and COADE) by posting ideas and questions forcomment from other users. These forums often provide alternativeview points to real world engineering problems encountered by ourusers.

The “Newsletters ” link produces a page listing all of the past issuesof Mechanical Engineering News . Complete newsletters in PDFformat are available as far back as 1993. Before 1993, only themost important articles from the newsletters are available.

The “Technical Articles ” link produces a list of COADE software

products, from which users can view a variety of articles specific toeach product. Articles here include FAQs (Frequently AskedQuestions), technical issues, and code comparisons. Articles onusing new features of the software can also be found here.

The “Reference ” page produces a list of publications highlyrecommended for users of COADE products. Most of these textshave been used by COADE in the development of the software and,therefore, make an excellent addition to your library.

The “Links ” page produces a list of other websites that may be of interest. This list includes COADE dealers, engineering societylinks, vendor links, computer related links, search engine links, andothers.

A regular review of the COADE website will keep you up to datewith the most recent edition of the software, provide access to theCOADE newsletters, and technical articles, and in general, keepyou informed of the latest developments at COADE.

CAESAR II Version 4.20Introduces New 3D Interactive

Graphics (by: Richard Ay)

One of the major enhancements to CAESAR II incorporated in the4.20 release is the new 3D graphics engine. This new graphicsengine is based on the HOOPS library. COADE is activelyincorporating HOOPS into its software, i.e. PVElite and CodeCalcThese new graphics provide the CAESAR II user with additionalreview capabilities, as well as more powerful interactive controlover the model. The following paragraphs discuss many of thesenew 3D graphics features.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



8

The HOOPS Graphics Context Menu:

Most Windows software programs support Context menus, availableby clicking the right mouse button. These Context menus vary incontent according to the currently active software window, hencethe use of the term context . The HOOPS graphics in CAESAR II

also support a Context menu. While in the 3D graphics, clicking theright mouse button brings up the context menu shown below. Eachof these menu choices displays a secondary menu with variousgraphics operations.

The first menu option is Operators , which contains options for theglobal manipulation of the graphic image. The second menu optionis Views , which contains options to quickly orientate the image intothe three standard planar views and the isometric view. The thirdmenu option is Projections , which provides various viewing options.The fourth menu option is Properties , which presently only providesa single option to change the colors of the various plot items. Eachof these menu options is discussed in the paragraphs below.

The Operators menu provides global manipulation options, asshown in the figure below. These operations are:

Annotate Used to place user defined text on the plot, from aleader line. Note, this text cannot be saved withthe job.

Element Select Used to select a particular element. A smallinformation dialog pops up describing theelement ’s node numbers and delta coordinates.The [Spreadsheet] button can be used to bring upthe entire spreadsheet associated with the selectedelement.

Orbit Used to rotate the model with the mouse.

Pan Used to move the model within the Window.

Zoom Extents Used to zoom out such that the entire model canbe seen in the Window.

Real Time Zoom Used to activate an interactive zoom , wherebymoving the mouse left and right zooms the modelin and out.

Zoom Window Used to zoom on a specific region of the model,using a standard rubber band box .

The Views menu provides four predefined views. Using theseoptions, you can quickly rotate the model to a specific orientation.These views are:

XY Plane This option produces a view looking at the modelin the “XY ” plane, looking down the “Z” axis.

XZ Plane This option produces a view looking at the modelin the “XZ ” plane, looking down the “Y” axis.

YZ Plane This option produces a view looking at the modelin the “YZ ” plane, looking down the “X” axis.

Isometric This option produces a standard Isometric view.

The Projections menu provides three different viewingperspectives. These perspectives are:

Orthographic This option produces an orthographic view of themodel.

Perspective This option produces a perspective view of themodel. This is probably the most useful view.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



9

Stretched to Window This option produces a stretched viewof the model, such that the model fills the entireWindow.

The Properties menu provides a single option to manipulate thecolors of the display items. This color control option produces thedialog shown below. Selecting an item in this list and clicking onthe [Change] button produces the standard color control dialog.

The rotating spring hanger is used to actively view the colorselection combinations before altering the entire plot window. This

is a useful tool to prevent the user from selecting unsatisfactorycolor combinations that would make information invisible.

HOOPS Manipulations:

Another feature of the HOOPS Graphics is the ability to adjust thegraphics toolbar for the purpose of rearranging or removing buttons.There are a number of ways to make these adjustments as discussedhere. The first method is to right click on the tool bar. This willbring up a button, shown in the figure below, which activates themodification dialog box.

After clicking this [Customization Button], a dialog box is presentedwhich allows for the removal or reordering of all toolbar buttons.Buttons can be removed by moving the selector in the right hand listbox to the desired button, and clicking on the [Remove] button.(Removed items can be put back on the toolbar by selecting them inthe left hand list box and clicking on the [Add] button.) Buttons can

be reordered by selecting them and then clicking the [Move Up] or[Move Down] buttons. This modification dialog box is shown inthe figure below.

In addition to the use of this formal customization dialog, individualbuttons can be removed or repositioned by holding down the [Shift]key and dragging the necessary button. To remove a button, drag itoff the graphics window, using the left mouse button. To repositiona button, drag it to the desired location, using the left mouse button.

Multiple viewports is another user-controllable feature of the HOOPSgraphics. CAESAR II has provided the 4 Views graphics optionfor many years. This option, however, provides only four staticviews: X axis, Y axis, Z axis, and Isometric. The HOOPS graphicson the other hand provide up to 4 views, that can be sized, rotated,

and annotated by the user. The figure below shows the initialHOOPS view when these graphics are activated. Notice the twosplitter bars , one at the far left of the lower scroll bar, and one at thevery top of the right scroll bar.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



10

Using the left mouse button, grab the lower left splitter bar and dragit to the right. This will split the graphics window into two panes,left and right. When the mouse button is released, both panes areupdated, with the Z axis view in the left pane and the isometric (ororiginal view) in the right pane. This modification to the graphicsview is shown in the figure below.

Again using the left mouse button, grab the upper right splitter bar and drag it down. This will split the two existing panes into twoadditional panes, upper and lower. When the mouse button isreleased, all four panes are updated, with the Z axis view in thelower left pane, the isometric (or original view) in the lower rightpane, the X axis view in the upper left pane, and the Y axis view in

the upper right pane. This modification to the graphics view isshown in the figure below.

The image in all of these panes can be manipulated individually.Each pane can be rotated, panned, or zoomed independently of theother panes.

Element Details:

Data interrogation has always been the most important feature of the CAESAR II graphics system. Users must have the capability toensure the correct model is being analyzed. The HOOPS graphicsexpand these interrogation abilities.

For quick details about an element or node point, click on theObject Selection Button (the white arrow pointing to the upper left).Now put the mouse cursor over the object of interest. An “informatiobubble ” will appear describing the major properties of the objectbeneath the cursor. A typical “information bubble ” is shown in thfigure below.

Moving the mouse cursor off of the piping system causes this“information bubble ” to disappear. Pointing to a different object,displays its “information bubble. ”

Previous versions of CAESAR II allowed users to view elementdiameters, thicknesses, and temperatures by simply placing valueson pipe elements. The new 3D graphics instead generate a colortable, where each color represents a different diameter, or thickness,

or temperature. The corresponding pipe elements are shaded in thesame color. The thickness data is shown in the figure below.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



11

One of the most useful features of the new 3D graphics system is theinteractive association of the graphic elements (i.e. the pipes) andthe input spreadsheet. Using the Object Selection Button (the whitearrow pointing to the upper left), click on any element in the model.If the spreadsheet is being viewed simultaneously with the graphics,the spreadsheet data is reset to correspond to the element graphicallyselected. This is shown in the figure below.

This figure shows that element 75-80 has been selected (since it hasbeen redrawn in gray). The spreadsheet has been updated tocorrespond to the data associated with this same element, 75-80.

Assuming enough screen real estate is available, the entirespreadsheet for the selected element can be viewed and its datamodified.

These new 3D graphics are under continual development. Eachnew revision to CAESAR II will provide more features andcapabilities to the graphic representation of the model.

Using CAESAR II ODBCData Export

(By: Pat Jenakanandhini)

Before the release of CAESAR II 4.20, users of the stress analysis

program frequently requested that we include a feature forcustomizing the stress, force, and other reports. These customizationrequests frequently dealt with formatting issues like font settings,page margins, etc. Therefore, in CAESAR II version 4.20, weimplemented ODBC export, which allows the user to create andchange reports in a way that was not possible in previous versions.This article will explain the benefits of the new feature and how itcan be used to the fullest advantage.

The ODBC export feature in CAESAR II uses Microsoft ® Access ™

to enable the user to create reports that display selected data in acustomized format. Access allows the creation of custom reportswhose formatting features can be manipulated like those of aMicrosoft ® Word ™ document. Using the CAESAR II ODBC exportfeature requires setting up a data source name (DSN). Instructionsare provided in the CAESAR II 4.20 User Guide (page 3-18).

For users who are not familiar with Access ™, the following is a brief description of the terms used in this article.

• What is a database? A database is a collection of data that isorganized so that its contents can easily be accessed, managed,and updated. The most prevalent type of database is therelational database, a tabular database in which data is definedso that it can be reorganized and accessed in a number of

different ways.• What is a table? A table is a collection of data about a specific

topic, such as products or suppliers. Using a separate table foreach topic means that you store that data only once, whichmakes your database more efficient and reduces data-entryerrors.

• What is a query? A query is a set of search conditions that isenacted on database tables. Queries are used to view, change,and analyze data in different ways. You can also use them asthe source of records for reports.

• What is a report? A report is an effective way to present data

in a printed format. Reports allow control over the scope andpresentation of data, allowing the user to display the informationas required.

• What is a filter? A filter is a set of criteria applied to data inorder to show a subset of the data or to sort the data.

Access ™ is a program that combines the above features into oneapplication. It is part of the Microsoft Office ™ suite and is availablewith the Professional Edition.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



12

CAESAR II version 4.20 is accompanied by a template databasethat contains sample reports. The current template database, updatedwith the 000502 build, includes a convenient form (automaticallydisplayed) for accessing the reports and six tables that hold all dataresulting from the static analysis of a model:

•RESTRAINTS: Contains calculated results of all restraintsused in the module.

• DISPLACEMENTS: Contains calculated results for alldisplacements the model undergoes.

• LOCAL_ELEMENT_FORCES: Contains calculated resultsfor all local forces and moments experienced by elements inthe model.

• GLOBAL_ELEMENT_FORCES: Contains calculated resultsfor all global forces and moments experienced by elements inthe model.

• STRESSES: Contains calculated results for all stresses, codestresses, and SIF ’s for elements in the model.

• HANGERS: Contains calculated results for hangers used inthe model if applicable.

At the present time, only static results are available for ODBCexport. To query these database tables for reports, the user mustfirst enable the ODBC Data Export function. The program will thenrequire the user to specify a location to which the database will besaved. From this location, the user can access the report templates.Shown below is the form provided for accessing the reports.

Figure 1: Report choice form from CAESAR II templatedatabase

Several jobs can be exported to the same database. Therefore, theuser must first choose the job name from JOBNAME list box orselect the View All Jobs check box.

After selecting the job name from the list, the user then selectswhich reports need to be viewed or printed. These choices can bemade by selecting the appropriate check boxes as shown below.

Figure 2: Selecting type of reports for view/print

With the job name and report chosen, the user can then either viewor print the report. The user also has the ability to view the report byload case or by element/node. In the first case, the load cases arelisted with elements/nodes under them. In the second option, the

elements/nodes are listed by load case. The report chosen will bedisplayed as shown below.

Figure 3: Screen capture of sample report

The above discussion focused on how to use the existing reportsavailable through the template database. Access ™ allowCAESAR II users to selectively view and print data through filtersand queries. The filter method is easier to use, but the query methodoffers more flexibility.

Filter Method: The following steps outline the process of applyinga filter:

1. Open the database specified in the CAESAR II ConfigurationSetup module.

2. Select the Tables tab or button and double-click on the nameof the table. The table is then displayed as shown below.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



13

Figure 4: Stress table

Note : If the table contains data from different jobs, apply the firstfilter to the job name.

3. Apply a filter to any of the fields in the table. The filter optionscan be accessed by right-clicking on the field where the userwishes to apply the filter. For example, if you want to onlyview data for the job CRYNOS._A, right-click on any

JOBNAME row with the data CRYNOS._A and select Filter By Selection as shown below. A filter will then be applied thatonly shows records from CRYNOS._A.

Figure 5: Filter by selection

4. The user can export the resulting data to Microsoft Word orMicrosoft Excel for formatting or analyzing. These featurescan be accessed by selecting Office Links from the Tools menuin Microsoft Access as shown below:

Figure 6: Office links export

A user can also opt to use the Filter Excluding Selection . Thisfeature is most useful when the user wants to view only recordsbelonging to either the sustained (SUS) or expansion (EXP) loadcases. To do this, select the operating (OPE) load case and thenapply a filter excluding the selection.

Another option is to use Filter For to search for specific nodes orelements exhibiting certain characteristics. For example, the Filter For option can be used to search the PRCT_STRF or thePRCT_STRT fields for values greater (> operator) than 90. Sincethose fields hold percentages of code stresses versus allowablestresses, it would be a quick way of reviewing elements that are

either overstressed or close to being overstressed.

Important Note: The filter option by default uses the logical ANDoperator to conduct searches. Therefore, when searching values of PRCT_STRF, PRCT_STRT, or any other numerical fields, caremust be taken not to mutually exclude filters. For instance, if thereare values specified for both PRCT_STRF and PRCT_STRT, thefilter will attempt to obey both filters and may not find any data,whereas there might be elements where only the FROM node i.e.PRCT_STRF will be overstressed. In such a case, the user shouldopt to use the query method that is more flexible.

Query Method: The following steps will outline how to create a

simple query for displaying elements that are overstressed.

1. Open the Access database as specified in the CAESAR IIConfiguration/Setup module.

2. Select the Queries tab or button and then pick Create Queryin Design View .

3. As prompted, select the table to be queried as shownbelow:

Figure 7: Table selection for query wizard

4. To review overstressed elements, select the STRESSES tableand click on Add . Then click Close to finish the table selection

process.5. Select all the fields in the table by double-clicking on the * as

shown below.

6. Pick the JOBNAME, PRCT_STRF, and PRCT_STRT fieldsto set criteria for those fields. The JOBNAME field containsthe name of the job(s) that exist in the database. Note that thename needs to be enclosed in quotations. The PRCT_STRF

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



14

and the PRCT_STRT fields contain the percentage of codestress compared to the allowable stress for the FROM nodeand TO node respectively.

Figure 8: Setting up the query

7. Specify the criteria so the data will be selected if PRCT_STRFOR PRCT_STRT is greater than 100. If the percentage isgreater than 100, then obviously we are dealing with anoverstressed element.

8. Test the query by clicking on the Run icon as shown here.

Figure 9: Run the query

If there are any overstressed elements in the model, the resultswill be displayed as shown below.

Figure 10: Query result

9. Save this query, so it can be used either in a report createdusing the Access report writer or can be exported to MicrosoftWord or Excel.

10. To create the report within Access, select the Reports tab anduse the Report Wizard to select the query created earlier.

11. To export the data to Word or Excel, select Office Links fromthe Tools menu.

The CAESAR II ODBC Data Export feature allows users toselectively create reports that address their concerns using commonlyavailable productivity tools such as Microsoft Office. Moreinformation about Access can be obtained from reference books.

COADE Inc. recommends that readers interested in furtheringtheir Access knowledge consult Microsoft Access 2000 Bible, byCary Prague and Michael Irwin, available at the COADE webs(http://www.coade.com) in association with Amazon.com and canbe found under the category Reference Materials.

Upgrading Databases fromAccess 97 to Access 2000

(by Pat Jenakanandhini)

When attempting to write CAESAR II output to an Access Database,an error message is displayed stating an “unrecognized formaerror ” has been encountered, as shown in the figure below. Whatcauses this?

This error occurs if a user has upgraded the user database specified in the CAESAR II Configuration file) to Access 2000.

CAESAR II 4.20 provides a template database in Access 9format. This was done so Access 97 users can use the data exportutility. The template database is stored in the CAESAR\SYSTEMdirectory.

To solve this problem:

1. Upgrade the template database.

2. Upgrade the User DSN to point to the upgraded templatedatabase.

Upgrading the template database:

1. Open Microsoft Access 2000 without opening any specificdatabase.

2. To upgrade the template database, go to the Tools/ DatabaseUtilities/Convert Database/To Current Access Database

Version as shown below:

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



15

3. You will be asked to select the database to convert FROM asshown below. Browse to the CAESAR\SYSTEM directory,pick CAESARII.MDB from the list and click Convert .

4. You will be asked to name the Database you are convertinginto. Name the file CAESARII2K.mdb and click Save asshown below. Make sure you save the file in theCAESAR\SYSTEM directory only!

You have now completed upgrading the template database to Access2000.

Updating the user DSN:

1. Select START/Settings/Control Panel/ODBC Data Sources.A window looking similar to the one shown below will appear.Select C2_OUT_ACCESS by clicking on it once and thenclick on Configure .

2. A window showing details of the DSN will appear similar tothe one shown below. Click on the Select button to change thedatabase affected by this DSN.

3. A browse window will appear. Select the file namedcaesarII2k.mdb and click on the OK button.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



16

4. You will notice that the DSN is now updated as shown below.DO NOT change the data source name. Click on the OK button and then again on OK to close the ODBC Data Sourceswindow.

You have now successfully updated your DSN.

CAESAR II will now allow you to export data results to Access2000.

Modeling Widely Spacedand Closely Spaced Miter Bendsin CAESAR II

(by: Dave Diehl)

CAESAR II automatically calculates and applies code-defined stressintensification factors (SIFs) to all identified points in the pipingsystem —tees, bends, and such. This SIF reflects the reducedstrength of the component compared to straight pipe (or, actually, agirth butt weld). The SIF is based on the flexibility characteristic of the component which is a function of the component geometry.This stress intensification factor allows the use of a material (andtemperature) basis for allowed stress without worry of componenttype. It ’s simpler to increase the calculated stress rather thanreduce the allowed stress level throughout the system. This SIFdata was developed in A.C. Markl ’s work published in the late 40 ’sand is found in most piping codes (e.g. B31.3 Appendix D) in usetoday. This article examines the definition and treatment of two of these components —the closely spaced and widely spaced miterbend.

Definitions

A few definitions are in order. A miter joint is a change in pipedirection through proper cutting and welding of straight pipe. Asingle cut, 90 degree miter has two pipe ends prepared at 45

degrees, a two-cut 90 degree miter uses three pieces each with a 30degree end, and so on. The number of cuts is required informationfor miter definition in CAESAR II . Think of the number of cuts asthe number of changes in direction through the joint. (The overallchange in direction is determined by the pipe entering and exitingthe miter joint.) Appendix D of B31.3 clearly shows that a closely

spaced miter group (c-s) acts as a single component, such as anelbow, while a “group ” of widely-spaced miter joints (w-s) aretreated as individual joints separated by straight lengths of pipe.This distinction is required in CAESAR II input as well. Thquestion then is, how far apart can these cuts be before a c-s groupbecomes a set of individual w-s cuts. The piping codes provide atest for this distance between cuts (or changes in direction) —if tspacing between cuts (s) is less than a certain amount tan1(2

θ+r s !

(where r 2 is the mean radius of matching pipe and θ is one-half anglbetween adjacent miter axes, the cuts are treated as a singlecomponent and, if the spacing is greater, the cuts are consideredsingle miters between straight runs of pipe. Of course, there mustbe at least two changes in direction to test for a closely spaced miter

since one cut, alone, is widely spaced.

What importance is this distinction between widely spaced andclosely spaced miters? What impact does it have on the CAESAR Imodel? A good place to find the answer is Appendix D of the B31codes – Flexibility and Stress Intensification Factors. This is wherea good part of Markl ’s work resides. Markl developed flexibilitycharacteristics (h) for piping components based on componentgeometry. This h value is used to calculate the flexibility factor (k)for the component. This flexibility factor is used directly incalculation of the component ’s overall stiffness as it is used inCAESAR II . Looking first at the flexibility characteristic —h bends, c-s miters and w-s miters is the same: 2

21 r RT ⋅ . Tequations for the miters appear different in Appendix D because thebend radii (R 1) in each case is replaced with the parameters fromwhich they are derived —for c-s miters 2cot1

θ ⋅= s R and for wmiters 2)cot1(21

θ +⋅= r R . Again, θ is one-half of the change indirection of the individual cut; θ = 45 ° for a single cut 90 degreemiter and θ = 15 ° for a three-cut 90 degree miter. The flexibilityfactor, k, for both c-s and w-s miters is the same: 6

552.1 h . (T

flexibility factor for bends is h65.1 .) The in-plane and out-of-plane stress intensification factors ( ii & io, respectively) for almiters is 3

29.0 h . Except for the equivalent bend radius, R 1 t

closely spaced and widely spaced miters are treated the same.

CAESAR II Terms

To include the Appendix D flexibility and stress intensificationfactors, simply click on Bend in the input screen as you enter thebend (the bend node is the element ’s “To Node ”). Remember thathe overall bend or miter angle is defined by the orientation of theelements entering and leaving the bend. CAESAR II input for thbend or miter appears in the auxiliary data area of the screen. Asample is shown in Figure 1 below. The mitered component isspecified by entering an integer in the miter points field —entering

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



17

indicates a w-s miter while a value greater than one signifies a c-smiter. The angle theta used in the miter calculations is set by theoverall miter angle (angle) and the number of cuts(n) – nangle 2=θ . The bend radius or the “effective ” miter radiusdefaults to 1.5 times the nominal pipe size (long radius). Thisradius field should be updated to reflect the actual or effective

radius of the component. Determining this effective radius formitered components is simplified by the bend SIF scratchpad. Thisscratchpad calculates the miter spacing based on the overall bendangle and two user values —bend radius and number of miter cuts.This scratchpad is shown in Figure 2. Keep an eye on the miterspacing as you change the bend radius or the number of cuts. Thisvalue s is back-calculated from the equivalent radius formula for c-s miters – 2cot1

θ ⋅= s R . If this miter spacing is greater thanthe c-s spacing limit in the scratchpad, you have a widelyspaced miter and it must be coded as such—as straight runsconnected by single miters. Using the approximate default bendradius of 1.5OD, this means that a 90 degree miter requires morethan three cuts to be considered closely spaced. Alternatively, your

equivalent miter radius could be reduced to meet the spacingrequirement. A subtle point (developed in the example below) isthat CAESAR II will use the w-s values for flexibility and stressintensification for those joints that do not meet the c-s requirementseven if they are entered as a multiple-cut component.

Figure 1

Figure 2

“NOTE 23 The MITERED BEND at 20 is WIDELY SPACED.”

A typical user, in a rush to get results, will code through the miter joint by checking on bend and specifying the number of cuts. Thedefault radius is usually ignored. It will not be until the errorchecker that the program warns the user with Note 23 that themultiple-cut miter does not qualify as a multi-cut, closely spacedmiter component. This component should be modeled as a series of widely spaced (single) miters separated by straight pipe. What doesCAESAR II do in this situation? Again, if the number of cuts isgreater than one, a c-s miter is assumed. The overall miter angle isdefined by the pipes entering and exiting the miter and the bendradius will default to one and one-half times the nominal OD. The

program ’s error processor will check the calculated miter spacingand report if the mitered component fails the c-s check using theAppendix D definition of maximum spacing of closely spacedcuts — )tan1(2

θ +r s ! . If the group is considered widely spaced,CAESAR II will use the widely spaced flexibility and stressintensification factors in the analysis. (These w-s values will alsobe displayed in the bend scratchpad.). OK, so the program uses thewrong flexibility and stress intensification factors. How wrong arethey? Is it a conservative error? Using the data in the scratchpadabove, the difference between widely and closely spaced parametersis less than 20 percent and the program, in using the w-s data, willuse the stiffer, weaker numbers. You could say that it is conservative.Except for the effect of the straight pipe! Remember, the codetreats the c-s miter as a single component with the flexibility andstress intensification factors applied across the entire, multi-cutcomponent. The widely spaced miter data applies to the single cutand the spacing between the cuts is treated as regular pipe. What isthe effect of the straight runs on the widely spaced model? Thesignificance of the straight runs will be examined using “sensitivitystudy. ” Rather than trying to think through the mathematics, theprogram will be treated as a black box. Two small models will bebuilt, one with the straight runs through the miter and one without.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



18

If the results are similar, the model is not sensitive to the differences.If the differences are significant, the “better ” model should be used.

An Example

An example will review the concepts presented so far. Run a 12

inch nominal, standard wall, A106 Gr.B pipe from 10 to 20 ten feetin the Y direction with an anchor at 10. Specify a bend at 20 and,leaving the radius at 18 inches, enter 3 for the number of miterpoints. Add the second element from 20 to 30 as 10 feet in X.Check the bend scratchpad to review the miter spacing and stressintensification factors. This data is shown in Figure 2.

Bend SIF Scratchpad !

The spacing between cuts is shown as 9.646 inches and the stressintensification factor is 3.285. Checking the Appendix D calculationswith 1875.62

=r , °= 15θ ; 845.7)tan1(2 =+⋅= θ r s . With the

scratchpad spacing (9.646) greater than the limit for closely spacedmiters (7.845), either the equivalent radius should be reduced orthis group of miter cuts should be modeled as three single cutmiters. If changing the radius, either use the equation

))(tan)tan1()(2 / ( 21 θ θ +r R ! or test values in the bend scratchpad.

For this example, the miters will be modeled as a series of singlecuts.

A strategy for modeling the example as a w-s miter group

A three-miter component has two elements separated by these threecuts. For simplicity, we will replace the overall group with fourelements —these two elements plus two “extensions of the existingpipe in and out of the group (the existing Y and X runs). Using thescratchpad length L=9.646; these extensions will be L/2 long andthe two new runs will be L long. These four pipes will be boundedby the node sequence 100, 200, 300, 400, 500 and single miter cutswill be specified at 200, 300 & 400. In this example we willproduce a miter group that maintains the face-to-face dimension of a standard welding elbow, i.e. radius = 1.5OD = 18 inches. Thespacing between cuts, then, will be the same as the scratchpad valueof 9.646 inches. The extensions will be half that or 4.823 inches.Now add these new elements. First break 10 to 20 (the ten foot runin Y) 8 to 6 from 10 (18 inches from 20) by adding node 100. Thefour miter elements will be inserted after this new element 10 to

100. Insert 100 to 200 as a 4.823 inch (L/2) run in the Y direction.For easy input, all new elements will be entered in the Y direction.The orientation of the new elements will be set in a second passthrough the group. Now insert 200 to 300 after 100 to 200 andmake it 9.646 inches (L) and follow it with 300 to 400, also L longand finally, 400 to 500 4.823 inches or L/2 long. Adjust theorientation of the new elements using the Block and Rotate featuresof the List Processor (see Figure 3).

Figure 3

First, in the element list, block the three elements 200 to 300through 400 to 500. Rotate this block –30 degrees about the Z axis(again, 10 to 20 was in Y and 20 to 30 was in X). The overallchange in direction is 90 degrees and with three cuts, each changewill be 30 degrees. Now block only 300 to 400 and 400 to 500 and

again rotate –30 degrees about Z. Finally block and rotate 400 to500 the same –30 degrees about Z. Now go back to the inputscreens and specify bends at 200, 300, and 400 with Miter Points =1. To clean up the model, delete element 100 to 20 and break 20 to30 by adding node 500 18 inches from 20 and delete element 20 to500. The plot should look good and the bend scratchpad will showthat s = 9.646 inches and the SIF is 3.285. These are the w-s miternumbers. If you would change the equivalent radius now, thespacing would change but since the number of cuts is 1, the flexibilityand stress intensification factors will stay at the w-s calculationsthe spacing has no effect on w-s miters.

Comparing the results of the correct and incorrect model—asensitivity study

How does this new model compare with the improperly coded, 3-cut miter model? A quick analysis of this simple system will revealthe significance of this proper model. Place a –0.1 inch displacemenat node 30 on both the “quick & dirty, ” miter = 3 job and the fancy,3 single-cut job and run an analysis of the displacement case. Theanchor load on the incorrect model is –178 lbf and the anchor loadon the correct model is –219 lbf. The maximum stress in theincorrect model is 1600 psi and the maximum stress in the correctmodel is 1889 psi. The stresses change but not as a result of theSIF ’s; these stress intensification factors are the same in both

models. It is the bending moments that are different and these aredifferent because the correct model is stiffer —those short, straighruns do play a role here. The numbers here are low but the change isabout 20 percent. The model is sensitive to this change.

You might have seen Note 23 (The MITERED BEND …WIDELY SPACED) in the error checker and ignored it in the past.You might not have known the reason or impact of such a modelingcondition. If you knew what it meant, the remedy might have beentoo costly —with confusing angles and lengths of pipe. Here, we

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



19

have reviewed the background and cause of this message byexamining the nature of closely spaced and widely spaced miteredcomponents. If there is more than one miter cut specified for aCAESAR II “bend, ” it better be a closely spaced miter. If itdoesn ’t pass the c-s miter test, CAESAR II will apply flexibilityand stress intensification factors for a w-s miter, but that will not

fully address the issue. The individual runs between cuts should bemodeled. This article reviews a quick and painless way to buildthat model and it illustrates the significance of that change.

Beam Element Modelsand the ASME B31 Codes(by: John C. Luf, Morrison Knudsen Corporation, Cleveland, Ohio, U.S.A.)

In the 1920s through 1950s Markl et al. performed their first set of fatigue tests on piping components and wrote his benchmark paper“Piping – Flexibility Analysis. ” Afterwards and in conjunctionwith this paper, the B31 rules for “Expansion and Flexibility section6” were modified by Markl and subgroup(s) members …H.C.E.Meyer, R. Michael, S.W. Spielvogel, N. Blair, H.V. WallStrom.For the most part, these changes have gone largely unmodified andMarkl's work is still quoted and referenced today.

The codes (B31.1 and B31.3) approach is predicated to a greatextent upon “simplified ” methods of analysis and evaluation, i.e. nodesign rules per Section III NB3200 “Design by Analysis ” etc. Assuch, the single dimension beam element structural analysis programssuch as CAESAR II and other “Pipe Stress Analysis ” programshave been used quite successfully for a wide variety of piping

systems. Code (SIFs) Stress Intensification Factors and flexibilityfactors improve the analytical results of these programs. The codesassume that the predominant loads imposed by weight, displacements,and other loads (not including pressure) primarily result in bendingstresses.

Limitations of beam elements…

CAESAR II ’s beam elements, like all beam elements, are unable todo certain things. Richard Ay quite often refers to CAESAR IIModel Elements as Stick Figure Elements. What he means by thisis, in essence, the beam element is a single dimensional entity. Itdoes not know where its O.D. is per se. It only knows mathematically

what effect the O.D. has on its structural strength and stiffness.Likewise in the three dimensions x, y, and z it only knows where itscenterline (or neutral axis is).

Also because of this, it does not know where the stresses CAESAR IIcalculates are on an element, i.e., top side or bottom of the pipe isnot known; therefore, calculated stresses are along the centerlineonly.

Static Modeling pitfalls…(The Missing Mid Span Node)

First, we will explore the concept that data output at any particularpoint requires a node.

Typically, when busily engaged in creating a model, the analystgoes from point to point (from fitting to fitting or support point tosupport point) and does not necessarily give thought to the issue of whether additional data nodes are required. Ordinarily this mightresult in an incorrect model, which would give incorrect results. Atypical single pipe element from a model might look like Figure 1. Iam sure that a lot of people go along from support to supportwithout any added considerations. However, this can lead to someincorrect results.

If this span was not based upon a precalculated span chart and it wascritical to determine the maximum bending stress combined with

pressure Sl and the maximum sag, this model would yield thefollowing results ….

When we look at the sustained stress calculation results, things atcasual glance appear to be fine …

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



20

One might notice that the highest sustained stress is shown at node10. However, the calculation of the code stress Sl is a combinationof bending stress due to weight + axial pressure stress. Therefore,the maximum bending stress should be at the midpoint of theelement and could be based upon the classic beam formula …

Mmax occurs at midspan but look where CAESAR II thinks themaximum stress is! Not at midspan, what happened?

Loading

M max at point (C)

Mmaxw l

2⋅

8:=

Well let ’s take a look at sag or deflection. Looking at Fig. 3 we seethat CAESAR II shows that there is no sag!

CAESAR II must be broken you say! Well as the Old Frenchproverb states “It is a poor workman who blames his tools! ” Letsmodify the model by adding a single node!

Looking at the improved model (Fig. 4)(improved by adding amidspan node), we see the following result for stress:

All of sudden things make sense again! So maybe there is nothingwrong with CAESAR II after all.

Looking at a deflected plot (Fig. 5), things now make sense as well.

If we would add many nodes the deflected plot would assume thecorrectly curved shape, but the mid span deflection of –2.70would not change.

So what happened? Well the only way that a beam element programcan extract data from a model is at node points. The only placeswhere mathematical results can exist are at node points. In the firstmodel, the analyst busily built the model without asking thequestion … “At what locations am I likely to pick up the maximumstress of any code type stress? ” If this would have been considered,the analyst would have added the midspan node. Well shouldnCAESAR II have known this and added a node?

Currently no beam element program that I know of is equipped with“Artificial Intelligence ” of this type. Therefore, the analyst needs toprovide adult supervision of the program at all times. Conversely inthe hands of an unskilled person any computer program will yieldinaccurate results. In instances where failures have gone to court(Hartford, Connecticut Arena roof collapse) invariably the unskilleduser is held to account for the mis-modeling.

One thing that CAESAR II does by default in the current version isto add a mid point node on an elbow. This small change is anenormous help. Previously, users could identify an elbow so thatthe correct Code SIF was applied but lacked the mid point node.This lack of a node on occasion could result in a “missed ” histress in an elbow, similar to the above example.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



21

The missing small diameter Sockolet/ Weldolet/ Pipet

These welded attachments are commonly used for all types of pipe-on-pipe intersections. They are commonly used for drains, vents,and instrument connections. Clearly in B31.3 and B31.1 they areassigned SIFs. Yet most analysts ignore their increase in SIF for

both the header location as well as the branch. The addition of thisto a pipe element that is part of the header, is branch diameterindependent! A copy of B31.3 Table D300 shows that the formulasfor k, i o , I I , and h do not require the branch geometry to come intoplay at all.

Once more, no node and no SIF may mean an incorrect andoverstressed system.

Localized effects

In the real world, round cylinders do not behave as a singledimensional beam element does. What I mean is that in a beamelement model, the circular properties are assumed constant fromone end of the element to the other. This is ordinarily not aproblem; however, it may lead to under-estimation of stresses insome cases. I quote B31.3:

TABLE D300 NOTES (1) Stress intensification andflexibility factor data in Table D300 are for use in theabsence of more directly applicable data (see para. 319.3.6).Their validity has been demonstrated for D/T ≤ 100.

What this means is, the simple SIFs and Flexibility Factors in thecode(s), which beam element programs such as CAESAR II use,may not be appropriate for very thin high D/T ratio pipes. Indeed

when you realize that Markl's original work was based on 4NPSstandard weight pipe (D/T=19.6) you should realize the farther youstray from that D/T, the less accurate your SIF and flexibility factorswill be. (And, no, 99.99 is not necessarily OK, and 100.01 is notnecessarily wrong.)

Other local effects that CAESAR II and other beam elementprograms do not deal with are the localized effects of line loads.Line loading is what occurs when a cylinder sits upon a flat surface.This effect is discussed in Tom Van Laan ’s book “Piping and

Piping Support Systems ” ISBN 0-07-058931-3. The program willgive a weight reaction at a +y support in the model. If the cylinderis a high D/T ratio pipe with a large pressure load and small contactlength the local wall may become overstressed.

Line Contact

Hidden thermal growth

The assignment of boundary conditions at supports is sometimes

done in the flick of a keystroke with no regard to what may really behappening. An example that comes to mind is secondary thermalgrowth at a point of pipe support.

18"6"

24 NPSPipe

Water CooledPedestal

Pump Case

Side View of pump and suction piping

3"Insulation

For example take a design where a fixed support is placed close to apump nozzle on a high temperature system (say 600 °F). At thistemperature carbon steel will grow approximately 1/16 ” for everyfoot of metal. In the side view is an example of a base trunnion usedto support a piece of very hot process piping.

Now ordinarily one would hope to see a spring can in a locationclose to a sensitive piece of rotating equipment, but the analyst sawno problems with the load reactions on the pump nozzle.

Indeed when you looked at the restraint loads they were withinallowable loading and yet evidence from the field suggested that thepump was overloaded. When one looked over the modeling, thebeam element model was made up in a simplistic fashion. It takes

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



22

very little imagination to see that the simple model missed theadditional 1/16 ” + upward growth of the trunnion. When thishidden growth was accounted for, the overturning moment on thepump was enormous! Yet here again the analyst had acceptableloads from the model. “The print out all looks good the pump mustbe bad! ” Well I guess that ’s why fixed supports around hot equipment

are a bad idea. It also reinforces the notion that single dimensionbeam element models must be given adult supervision at all times.

Side View of pump and suction piping

RR

Anchor

+ Y

Caesar IINodes

What’s in a code?

CAESAR II , when used with either B31.3 or B31.1 as a pipingcode, analyzes piping systems per those codes rules. SIF, flexibilityfactors and load combinations are automatically selected. Howeverlets look at some interesting facets of these rules.

Feeling squeezed?

Both of these codes presume that your piping system is somewhat“normal, ” as far as layout and restraints are concerned. What do Imean by “normal ”? Well let ’s take a look at the following situation …

Interesting isn ’t it? I have seen people have layouts just like thisburied in the middle of an involved system. Lets see what guidancean analysis gives us.

Neither B31.1 nor B31.3 provide any specific guidance compressive loads. B31.3 does advise the designer to evaluate forthem and to be watchful of them.

Beam element models are unable to predict the complex nature of buckling phenomena. It is three dimensional in nature, besideswhich, who would ever want to have a design with over a half million pounds of restraint load????

Summary of concepts:

" The B31.3 and B31.1 codes are simplified codes. They do notprovide specific direction on three-dimensional analysis of piping systems ala three-dimensional finite element models.

" The code SIFs and flexibility factors shown in, for instance,Table D of B31.3 are used by beam element models to providea more realistic set of reactions and stresses. These factorshave limitations based upon D/T ratios as stated in the B31.3code.

" The analyst should place nodes in areas of probable highstresses or deflections. The analyst must have some feel what is being analyzed prior to the modeling effort. In case of doubt, add a node(s).

" If a high stress or a deflection occurs in a location without anode at or near it, the beam element model will “miss ” tstress/deflection.

" Secondary growth issues should always be considered.Remember the beam element does not know where the diameter

of the element is. Don ’t be misled by full volume or renderedplots that show pipe outer diameters.

" Local effects such as line loads must be reviewed by methodsother than the Beam Element model; this effect is particularlyacute in higher D/T ratio piping.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



23

" If you are designing pipe columns neither CAESAR II , northe B31.1 and B31.3 codes are very helpful. This phenomenacan and does occur in jacketed piping systems where the coreand jacket pipes experience different temperatures. BeAWARE OF THIS SITUATION!

" Adult supervision OF ANY COMPUTERIZED SOLUTIONIS ALWAYS NECESSARY! Experience and judgment area prerequisite to successful use of any CAE tool.

" When modeled correctly and used within the norms of expectedbeam element behavior in systems where bending loads arethe predominant issues of concern, beam element modelshave been quite successfully used in combination with ASMECode factors. The knowledgeable analyst can extend the useof beam element models into higher D/T ratio piping systemanalysis by addressing localized concerns.

Undocumented CAESAR II Gems(by: Dave Diehl)

A couple of months ago I was building a CAESAR II buried pipingmodel. I defined the soil data and defined which sections wereburied and clicked on “bury the system. ” Once the program listed“ Model conversion complete, ” I realized an input error and, insteadof clicking on either the “OK ” or “Cancel ” buttons at the bottom of the window, I clicked on the Close (X) button at the top right cornerof the window. The restraints were not added and control wasreturned to the Underground Pipe Generator but I was surprised tofind that the model now had all the extra soil model nodes. Rightaway I remembered a previous user request …

Soil provides continuous support along the pipe. CAESAR II hasno continuous support model. Instead, for buried pipe, CAESAR IIadds a series of regular point supports along the line. However,there are two soil effects to consider —soil friction which loads thepipe axially and soil bearing which loads the pipe in the lateraldirection (see Figure 1). The buried pipe modeler addresses boththe axial and transverse soil conditions by the density of pointsupports added to the line. A good bearing soil model (nearchanges in direction or at tees and such) requires many pointsupports while the axial soil model is adequately addressed withonly a few supports. The CAESAR II documentation refers tothese areas as Zone 1 and Zone 3 respectively. Zone 1 supportspacing is set by foundation theory with four nodes (three elements)equally spaced through this bearing zone, L b .

25.0)4(65.0tr

b K I E L ⋅⋅

⋅⋅= π K tr is the translational stiffness of the

soil. Zone 3 node/restraint spacing is simply 100*OD. Zone 2 nodespacing starts at 1.5 times Zone 1 lengths at the Zone 1 end andprogresses linearly to 50*OD at the Zone 3 end by adding twointermediate lengths. In addition, CAESAR II will add 1 or morenodes through the bend breaking the bend into two or more equal

length segments —similar to the Near/Mid/Far node sequencenormally built around bends. (The final number of elements, N,will satisfy the relationship: N < 3*pi*BendRadius/Lb<2.4*N.)

Figure 1

We have received requests from a few users who are not happy withthe number of restraints around the bend. The problem is the bendrestraints may not be close enough to eliminate bending around thenode —bending which would not be possible in a proper bearing/ foundation model. Again, CAESAR II is modeling the continuoussoil support by a series of point supports; if they are not closeenough, an unrealistic bending moment develops (see Figure 2).The obvious work-around is to break the bend “by hand ” into aseries of bends and let CAESAR II add the additional bend restraintsto each of these segments. This is not easy. You have to have agood handle on analytical geometry to set the tangent intersectionpoints for this series of small angle bends.

Figure 2

Well, here I am looking at a job that now has a whole lot more nodesaround the bend. The modeler even maintained the bend designationthrough these back-to-back “partial ” bends so each node is a changein direction with a bend. All I need to do is to continue in the buriedpipe modeler and bury this modified model once again. My nodedensity is automatically increased without me or CAESAR II doinganything more.

So, if you are running large radius (50*OD) bends (or any otherradius for that matter) through the buried pipe modeler, you can adda node at the start and end of each bend and “bury ” only the bends(by specifying a soil model number for these segments) on the first

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



24

pass and return to the soil modeler. Now with a denser node, pack around these bends, and bury the entire system to complete themodel.

The second “gem ” just came up last month at a trade show inGermany —ACHEMA 2000. A rather large user (in CAESAR II

work, not in personal stature) asked if we could add a feature in theprogram to relate their many isometric drawings to their respectiveCAESAR II analyses. I saw this as a legitimate and importantrequest but outside the scope of our program. My initial responsereflected my point of view —I said user discipline was the bestanswer. Organizing data in individual folders and controlling jobnames was the immediate solution to the user ’s dilemma. Hepersisted. He is responsible for more than a dozen CAESAR IIinstallations and the piping analyses may span several drawings. Itwould be difficult for him to control naming conventions and anymistakes would result in lost time in their correction.

Rising to the cause (or bait), I tried another approach. While he was

standing there I typed a string in the input title page, saved the job,and then used Windows Explorer to find that string. It worked! Ityped 12345 in the title page and saved the job. When I went out toWindows Explorer, I right-clicked on the folder I wanted to search,clicked on Find, and in the “Containing text ” field typed in 12345.Sure enough, Windows Explorer listed my CAESAR II input file.While not the elegant “programmed ” solution he was asking for, theuser now has a method of searching all CAESAR II jobs in a folderor directory for key words or phrases such as line number orequipment ID. This approach is readily available to all who use thetitle page in annotating their analyses.

WRC 107: Elastic Analysis vs.Fatigue Analysis

(by: Mandeep Singh & Tom Van Laan)

This article aims to clarify the use of the Welding Research Council Bulletin 107 to perform Elastic and/or Fatigue analysis on vessel-attachment junctions. The topic is complex and the user is advised to refer to the WRC Bulletin 107, ASME Section VIII Div. 2

paragraphs: AD-160, AD-560, App. 4 and App. 5, before usingthis software.

The Welding Research Council (WRC) Bulletin 107 is implementedin COADE ’s CAESAR II , CodeCalc , and PVElite programs. Inthe rest of this article, these programs will be collectively referred toas the “software ” unless otherwise noted.

In many cases it is necessary to check loadings on nozzles andattachments at the shell junction. As a result of these loadings, localstresses are induced at the intersection of the components. Theseloads can be determined from a pipe stress program such as

CAESAR II or PVElite in the case of lug supports. Stressclassifications for these loads are Primary, Secondary, and Peak.Primary stress is necessary to satisfy the equilibrium conditionswith the external imposed loading such as P*A and M/Z. It mayalso be called load-controlled stress (ASME Code Case N-47-28).They are not self-limiting in nature and can cause ductile rupture or

a complete loss of load carrying capacity due to the plastic collapseof the structure upon single application of load (ASME). Secondarystress is developed as result of imposed strain. Secondary stress is aglobal self-limiting stress. The examples include some bendingstresses and the stress due to thermal expansion; however, Peak stress is a localized self-limiting stress. It causes no objectionabledistortion but it may be a possible source of fatigue failure.Depending upon the type of loading, the design should be checkedfor these stresses.

Section AD-160 of the ASME VIII Div 2 Code provides theguidelines indicating when a fatigue analysis is required and whenan elastic analysis will suffice. One of the conditions for materials

with minimum tensile strength not exceeding 80 ksi is that the totalnumber of expected cycles does not exceed 1000. The expectedcycles include full-range pressure cycles, operating cycles, effectivenumber of changes in metal temperatures between two adjacentpoints in the pressure vessel and temperature cycles. (The usershould refer to Section AD-160 for complete list of guidelines.) Inan elastic analysis, the primary and secondary stresses are taken intoaccount and the effect of peak stress is neglected. For fatigueanalysis all the stress categories are evaluated in a combined manner.Peak stress is computed by applying both the stress concentrationfactors and Pressure Stress Indices, defined in the followingparagraph.

Peak stress intensities resulting from internal pressure are neededfor performing fatigue analysis. They can be computed using theSection AD-560 “Alternative Rules for Nozzle Design ” instead Article 4-6 ( “Stresses in openings for fatigue analysis ”) when all thconditions of AD-560.1 through AD-560.6 are met. This alternativemethod is implemented in the software. With this method, a basestress value is multiplied by certain factors to get the intensifiedstress at different locations in the shell. These factors are known asPressure Stress Indices and are given in the Table AD-560.7.Pressure Stress Indices, sometimes referred as Pressure StressConcentration factors, are only applied to the internal pressurestress.

Stress Concentration Factors Kn and Kb factors are used to computethe highest peak stress due to external piping loads. Peak stressesare usually localized at discontinuities such as fillets and transitions.The membrane and bending stresses are modified using the StressConcentration Factors Kn and Kb respectively. The program usesthe fillet radius between the Vessel and the Nozzle to estimate theKn and Kb values using WRC 107 Appendix B equations (3) and(4).

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



25

If an elastic analysis is the only requirement, then the followingpoints should be kept in mind when using the WRC 107 module:

• Set up different types of load cases (sustained, expansion andoccasional).

• Include pressure thrust if needed.

• Do not include pressure stress indices.

• Do not include stress concentration factors Kn and Kb (this isdone by omitting the fillet radius between the vessel andnozzle).

• Use stress summation to compare the actual stress to theallowable stress.

Stress Summation Method

The ASME Section VIII Division 2 code provides for an elaborateprocedure to analyze the local stresses in vessels and nozzles(Appendix 4-1 “Mandatory Design Based on Stress Analysis ”).This approach is used to compute the overall stress intensities onthe vessel/nozzle intersection. The local stresses resulting fromsustained, expansion and occasional loads are combined withpressure stresses into code-defined stress categories and comparedwith their respective allowable stress values. Hence, the nameStress Summation is used to identify the method.

If a fatigue analysis is required then elastic analysis will still berequired. Furthermore, there will be additional checks for fatiguestress. For performing fatigue analysis, we need to calculate orestimate Peak stress intensities. Fatigue analysis can be performed

through these steps:1. First, set up the range pair and load cycles (e.g. Installed to

operating, pressure fluctuations) for the fatigue loading.

2. Now evaluate each load range using the WRC 107 module oneby one. Enter each cyclic load as a sustained load and leave theother types of loads blank.

3. Include Pressure Thrust if needed.

4. Include stress concentration factors Kn and Kb, by enteringthe fillet radius between the vessel and nozzle. Doing so willcompute the peak stress due to applied loads.

There are two ways to combine the stresses due to external loadswith the ones due to internal pressure:

1. Calculate the pressure stress by hand (using AD-560.7 tomanually apply Pressure Stress Indices) and combine withstresses due to external loads. Do not check the checkbox toautomatically include pressure stress indices and do notperform stress summations.

Or

2. Automatically include the Pressure Stress Indices and performstress summations. Use the program's results for Stress Intensity(Pm+Pl+Q+F) and ignore the results for first two equations(Pm and Pm+Pl) and ignore the comparison to the allowable

stresses. This method is illustrated in the example below.

The total stress intensity (Pm+Pl+Q+F) is a combination of theeffect of external loads intensified by Kn and Kb factors andinternal pressure intensified by pressure stress indices. This is thePeak stress intensity needed for performing fatigue analysis. Nowuse this total stress intensity value in conjunction with ASMESection VIII Div 2, Appendix 4 and 5 rules and the fatigue curves tocompute cumulative usage.

The following example illustrates these topics using the CAESAR IIWRC 107. This is similar to the WRC 107 module in CodeCalc PVElite , but we will note the differences as we go along.

Example:

The cylindrical vessel ’s details are:

Vessel :Outer diameter: 120 inchThickness: 1.0 inch

Nozzle :Nominal diameter: 10 inch (10.75 inch actual )Schedule: 80S (thk. 0.5 inch)

Elastic analysis will be performed first followed by fatigue analysis.

Elastic analysis : For the elastic analysis, loads are specified insustained, expansion and occasional categories. The vesselinformation is entered first. The input for Fillet Radius betweenVessel and Nozzle should be left blank. This will serve as anindication to CAESAR II software that Stress Concentration Factors(Kn and Kb) should not be included in analysis (Fig. 1). InCodeCalc , there is an explicit checkbox for the same. Moreover,the “Include Pressure Stress Indices ” check box should be leftunchecked. Peak stress is neglected from the analysis by notincluding the effect of stress concentration factors (Kn and Kb) andpressure stress indices.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



26

Figure 1: Vessel Data

Nozzle data input is next. This is a radial nozzle along the X-axis.The direction of the nozzle is from the nozzle pointing towards thecenter of the vessel. This convention makes the axial force consistentwith the WRC 107 convention, in which the axial force ‘P’ ispositive pointing into the vessel. In this case the direction cosinesof the nozzle are (-1, 0. 0). Next, we will enter the forces andmoments acting on this nozzle.

On the input screen for sustained loads there is a check box thatprompts for inclusion of pressure thrust. Pressure thrust is the forceexerted on an attachment such as a nozzle due to the internalpressure of the cylinder to which it is attached. The inclusion of this

force depends on the flexibility, configuration, and restraintinformation of the piping system attached to the nozzle. Pressurethrust is a topic of a separate article and will be addressed in future.However, we will assume the piping system on the other side isflexible and the box will be checked (Fig. 2).

Next, the expansion and the occasional loads should be entered(Fig. 3). There is not an additional internal pressure in this occasionalload case, so that entry will be zero.

Figure 2: Sustained loads

The external piping loads can also be automatically brought in froma CAESAR II piping model ’s output by clicking the “Get Loafrom Output ” button. With a complete input, the analysis can beexecuted by pressing the appropriate button. The results will includestress intensity due to individual load cases. The Stress Summationoption in the software implements the rules given in Section VIIIDiv 2 for combining different types of stresses. Perform the stresssummation and examine the results.

Figure 3: Occasional loads

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



27

Vessel Stress Summation @ Nozzle Junction Division 2 Stress Indices not applied —————————————————————————————————————————————————————————————————————————————— Type of | Stress values at Stress Intensity | (lb./sq.in.) ——————————| ——————————————————————————————————————————————————————————————————— Location | Au Al Bu Bl Cu Cl Du Dl ——————————| ——————————————————————————————————————————————————————————————————- Circ. Pm (SUS) | 8850 8850 8850 8850 885 0 8850 8850 88 50 Circ. Pm (OCC) | 0 0 0 0 0 0 0 0 Circ. Pm (TOTAL) | 8850 8850 8850 8850 8850 8850 8850 8850

Circ. Pl (SUS) | 1350 1350 2922 2922 215 7 2157 1645 16 45 Circ. Pl (OCC) | -43 -43 743 743 493 493 129 129 Circ. Pl (TOTAL) | 1307 1307 3665 3665 2650 2650 1774 1774 Circ. Q (SUS) | 4578 -4578 8886 -8886 14539 -14539 4119 -4119 Circ. Q (EXP) | -37 15 107 -53 169 -145 -79 83 Circ. Q (OCC) | 26 -26 2180 -2180 5250 -5250 -2192 2192 Circ. Q (TOTAL) | 4567 -4589 11173 -11119 19958 -19934 1848 -1844 —————————————————————————————————————————————————————————————————————————————- Long. Pm (SUS) | 4387 4387 4387 4387 438 7 4387 4387 43 87 Long. Pm (OCC) | 0 0 0 0 0 0 0 0 Long. Pm (TOTAL) | 4387 4387 4387 4387 4387 4387 4387 4387 Long. Pl (SUS) | 1688 1688 2114 2114 249 4 2494 1778 17 78 Long. Pl (OCC) | 205 205 417 417 605 605 95 95 Long. Pl (TOTAL) | 1893 1893 2531 2531 3099 3099 1873 1873 Long. Q (SUS) | 6210 -6210 13020 -13020 9599 -9599 3827 -3827 Long. Q (EXP) | -44 48 136 -112 108 -76 -38 38 Long. Q (OCC) | -126 126 3278 -3278 3161 -3161 -961 961 Long. Q (TOTAL) | 6040 -6036 16434 -16410 12868 -12836 2828 -2828 —————————————————————————————————————————————————————————————————————————————— Shear Pm (SUS) | 0 0 0 0 0 0 0 0 Shear Pm (OCC) | 0 0 0 0 0 0 0 0 Shear Pm (TOTAL) | 0 0 0 0 0 0 0 0 Shear Pl (SUS) | 88 88 -88 -88 -148 -148 148 148 Shear Pl (OCC) | 88 88 -88 -88 -148 -148 148 148 Shear Pl (TOTAL) | 176 176 -176 -176 -296 -296 296 296 Shear Q (SUS) | 165 165 165 165 165 165 165 165 Shear Q (EXP) | 2 2 2 2 4 4 0 0 Shear Q (OCC) | 231 231 231 231 231 231 231 231 Shear Q (TOTAL) | 398 398 398 398 400 400 396 396 —————————————————————————————————————————————————————————————————————————————— S.I. Pm (SUS) | 8850 8850 8850 8850 88 50 8850 8850 8850 —————————————————————————————————————————————————————————————————————————————— S.I. Pm (SUS+OCC) | 8850 8850 8850 8850 8850 8850 8850 8850 —————————————————————————————————————————————————————————————————————————————— S.I. Pm+Pl (SUS) | 10201 10201 11773 11773 11012 11012 10500 10500 —————————————————————————————————————————————————————————————————————————————— S.I. Pm+Pl (SUS+OCC)| 10164 1 0164 1252 0 12520 11521 115 21 10643 10643 —————————————————————————————————————————————————————————————————————————————— S.I. Pm+Pl+Q (TOTAL)| 14854 5629 23798 10897 31458 8437 12608 8868 ——————————————————————————————————————————————————————————————————————————————

Vessel Stress Summation @ Nozzle Junction —————————————————————————————————————————————————————————————————————————————— Type of | Max. S.I. S.I. Allowable | Result Stress Intensity | (lb./sq.in.) | ——————————| ——————————————————————————————————————————————————————————————————— S.I. Pm (SUS) | 8850 23300 | Passed S.I. Pm (SUS+OCC) | 8850 27960 | Passed S.I. Pm+Pl (SUS) | 11773 34950 | Passed S.I. Pm+Pl (SUS+OCC)| 12520 41940 | Passed S.I. Pm+Pl+Q (TOTAL)| 31458 69900 | Passed ——————————————————————————————————————————————————————————————————————————————

Table 1: Results of the Elastic Analysis

The results are shown in Table 1. The maximum values of stress foreach of the eight locations are compared to the allowables, todetermine if the junction failed or passed. All the stress combinationspassed in this case. This completes the elastic stress analysis of thenozzle-shell junction.

Now suppose there are some cyclic loadings to consider. Theinformation needed to perform the fatigue analysis for the cycliccondition is shown below:

Temperature variation from ambient (70 °F) to 250 °F coupled withpressure variation of 200 psi: 10,000 cycles.

A pipe stress program such as CAESAR II can be used to set up therange load pairs and get the range loading from the output. Anarticle “Fatigue Analysis Using CAESAR II ” in the December1998 newsletter elaborates on performing the fatigue analysis (alsoavailable on COADE ’s website www.coade.com).

In this case, we get following range loading,

Fx = 2500 lbFy = 3500 lbFz = 2500 lbMx = 2600 ft-lbMy = 2900 ft-lbMz = 6000 ft-lb

In the WRC 107 module, we include the effect of the stressconcentration on external loads (by specifying the fillet radius) andinternal pressure (via a checkbox), as shown in the Fig. 4.

Figure 4: Vessel Data in the Fatigue case

The fatigue load case cannot be classified as sustained, expansionor occasional; however, in order to use the WRC 107 software, theloads must be entered under one of these categories. Since apressure value is also needed, these loadings should be “sustained ”loads. This will not make a difference for our purpose.

After running the WRC 107 analysis, you can use the stresssummation to automatically combine the stress intensity due tointernal pressure with the stress intensity due to external loading.(Note: This combination can also be done manually).

From the stress summation output, the maximum stress intensity isneeded for performing the fatigue analysis. This value is highlightedin Table 2.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



28

ANALYSIS REPORT: WRC 107

Vessel Stresses @ Nozzle Junction—————————————————————————————————————————————————————————————————————————————— | Stress values at Type of | (lb./sq.in.) —————————————————————| ——————————————————————————————————————————————————————— Stress Load| Au Al Bu Bl Cu Cl Du Dl —————————————————————| ———————————————————————————————————————————————————————— Circ. Memb. P -Pl | 3000 3000 3000 3000 2671 2671 2671 2671 Circ. Bend. P -Q | 8470 -8470 8470 -8470 11 737 -11737 11737 -11737 Circ. Memb. MC -Pl | 0 0 0 0 265 265 -265 -265 Circ. Bend. MC -Q | 0 0 0 0 4836 -4836 -4836 4836 Circ. Memb. ML -Pl | -1966 -1966 1966 1966 0 0 0 0 Circ. Bend. ML -Q | -4827 4827 4827 -4827 0 0 0 0 | Total Circ. Stress | 4677 -2609 18263 -8331 19 509 -13637 9307 -4495 —————————————————————————————————————————————————————————————————————————————— Long. Memb. P -Pl | 2671 2671 2671 2671 3000 3000 3000 3000 Long. Bend. P -Q | 1209 7 -12097 12097 -12097 8446 -8446 8446 -8446 Long. Memb. MC -Pl | 0 0 0 0 371 371 -371 -371 Long. Bend. MC -Q | 0 0 0 0 2679 -2679 -2679 2679 Long. Memb. ML -Pl | -533 -533 533 533 0 0 0 0 Long. Bend. ML -Q | -7631 7631 7631 -7631 0 0 0 0 | Total Long. Stress | 6604 -2328 22932 -16524 14496 - 7754 8396 -3138 —————————————————————————————————————————————————————————————————————————————— Shear VC -Pl | 148 148 -148 -148 0 0 0 0 Shear VL -Pl | 0 0 0 0 -207 -207 207 207 Shear MT -Pl | 171 171 171 171 171 171 171 171 | Total Shear Stress | 319 319 23 23 -36 -36 378 378 —————————————————————————————————————————————————————————————————————————————— Stress Intensity | 6655 2817 22932 16524 19509 13637 9443 4593 ——————————————————————————————————————————————————————————————————————————————

Stress Intensity due to external loadings

Vessel Stress Summation @ Nozzle Junction Division 2 Stress Indices are applied —————————————————————————————————————————————————————————————————————————————— Type of | Stress values at Stress Intensity | (lb./sq.in.) —————————————————————| ———————————————————————————————————————————————————————— Location | Au Al Bu Bl Cu Cl Du Dl —————————————————————| ———————————————————————————————————————————————————————— Circ. Pm (SUS) | 10620 27435 10620 27435 23010 -1770 23010 -1770 Circ. Pl (SUS) | 1034 1034 496 6 4966 2936 29 36 2406 2406 Circ. Q (SUS) | 3643 -3643 13297 -13297 16573 -16573 6901 -6901 —————————————————————————————————————————————————————————————————————————————— Long. Pm (SUS) | 4387 -877 438 7 -877 9214 43 87 9214 4387 Long. Pl (SUS) | 2138 2138 320 4 3204 3371 33 71 2629 2629 Long. Q (SUS) | 4466 -4466 19728 -19728 11125 -11125 5767 -5767 —————————————————————————————————————————————————————————————————————————————— Shear Pm (SUS) | 0 0 0 0 0 0 0 0 Shear Pl (SUS) | 148 148 -148 -148 -207 -207 207 207

Shear Q (SUS) | 171 171 171 171 171 171 171 171 —————————————————————————————————————————————————————————————————————————————— S.I. Pm (SUS) | 10620 28312 10620 28312 23010 6157 23010 6157 —————————————————————————————————————————————————————————————————————————————— S.I. Pm+Pl (SUS) | 11658 28469 15588 32401 25949 7764 25419 7022 —————————————————————————————————————————————————————————————————————————————— S.I. Pm+Pl+Q (TOTAL)| 15320 28038 28883 36505 42519 15407 32326 7551 —————————————————————————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————————————————————————— Type of | Max. S.I. S.I. Allowable | Result Stress Intensity | (lb./sq.in.) | —————————————————————| ———————————————————————————————————————————————————————— S.I. Pm (SUS) | 28312 23300 | Failed S.I. Pm+Pl (SUS) | 32401 34950 | Passed S.I. Pm+Pl+Q (TOTAL)| 42519 69900 | Passed ——————————————————————————————————————————————————————————————————————————————

Table 2: Stress Intensities for Fatigue case.

The primary membrane stress, which by definition is the averagestress across the thickness, is varying across the thickness as seen inthe results (Table 2). This happens because we apply pressurestress indices to compute the peak stress. The WRC 107 program

computed a stress intensity of 42,519 psi. This is actually the totalstress intensity including the effect of peak stress thus,

S.I: Pm + Pl + Q + F = 42,519 psi.

In a future release of the software, modifications will be incorporatedto make it easier to perform fatigue analysis. Since there is no stress

reversal, this is a stress range (Sr). Therefore, alternating stressintensity is,

Sa = 1/2 * Sr = 1/2*42519 = 21259.5 psi.

Correct the Sa for the design temperature in accordance with SectionVIII Div 2 Appendix 5 5-110.3(f) by multiplying by the ratio of modulus of elasticity given on the design curve to the value used inthis analysis.

S´a = 21259.5 * (30/29.25) = 21804.6 psi.

From the figure FIG. 5-110.1 in App. 5 Sec. VIII Div. 2 (for UTS80 ksi), shown here in Fig. 6, the number of allowable cycles are for21,805 psi. is:

N = 75,000 cycles (Allowed)n = 10,000 cycles (Actual)

Figure 6: Design Fatigue Curve (5-110.1) from Sec. VIII Div. 2

Therefore, the Cumulative Usage factor U is:

U = n/N = 10000/75000 = 0.133

U = 0.133 < 1.0 so the design meets the specified requirements.

If we have other cyclic loads, then their effect can be combined toobtain the total usage factor.

Utot = n1/N1 + n2/N2 + ……

Again the total usage factor must be less than or equal to 1.0 for adesign to be acceptable.

Maximum StressIntensity value forFatigue analylsis

Intensified StressIntensity due tointernal pressure

This is the StressIntensity of interest

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



29

Hardware / Software for theEngineering User (Part 29)

(by: Richard Ay)

This article will focus on the use of the Windows keys on the

keyboard, optimizing your use of Windows Explorer, and the relatedissue of “file associations. ” (The information for this article hasbeen obtained from Ziff Davis tips and PC Magazine.)

The Windows Keys:

Most newer keyboards include two Windows keys, outside of the[Alt] keys on the keyboard. These keys are labeled with theWindows logo. Simply pressing the Windows key brings up the“Start Menu. ” This seems like quite a waste —two keys to onlybring up the “Start Menu ”? What else are these Windows keys usedfor?

Actually, there are a number of things the Windows keys will do foryou, when used in combination with another key on the keyboard.These “key combinations ” are described in the table below. In thistable, the notation [Win] refers to the Windows key.

• [Win]+[E] This key combination launches WindowsExplorer. The result of launchingExplorer in this fashion is that its initialdisplay has all drives collapsed.

• [Win]+[F] This key combination launches the “FindFiles ” dialog box. Ordinarily, fromWindows Explorer, the “tool ” menuwould be used, followed by “Find, ” andthen “Files or Folders. ” This keycombination avoids this menu nesting,and displays the dialog directly.

• [Win]+[M] This key combination minimizes all openwindows to the task bar. This basicallyclears the desktop, while leaving allrunning applications intact.

• [Win]+[R] This key combination opens the “Run ”dialog box.

• [Win]+[Break] This key combination opens the “SystemProperties ” dialog box. Ordinarily, youwould have to “right click ” on the “MyComputer ” desktop icon, then selectproperties to obtain this dialog box. Thiskey combination displays this dialogdirectly.

• [Win]+[F1] This key combination brings up WindowsNT help, regardless of the currentprogram. [F1] alone typically brings upthe help on the current program.

• [Win]+[Tab] This key combination cycles through theprograms on the task bar. Once thedesired program has “the focus, ” [Enter]will bring its window to the top of thedisplay.

Windows Explorer :

Windows Explorer is the main file management / navigation tool forWindows 95, Windows 98, and Windows NT. Typically, when(Windows) Explorer is launched, its initial window displays thecontents of Drive C. There are a number of “command line switches ”that can be used to alter the way Explorer starts up. These “commandline switches ” are discussed in the following paragraphs. Fortesting purposes, it is suggested that a DOS box be utilized. Oncespecific configurations have been deemed desirable, they can be setin the “Target ” setting of the desktop shortcut.

• Explorer [Enter]This command launches Explorer, supposedly in “single paneview. ” However, testing reveals that this command results ina “double pane view ” with Drive C expanded.

• Explorer /n [Enter]This command launches Explorer, in a “single pane view. ”The content of the view is the Desktop. To change the view,the “drop list ” should be used. This will allow the selection of the various system drives.

• Explorer /e [Enter]This command launches Explorer, in a “two pane view. ” Thecontent of the view is the Desktop.

•Explorer subobject [Enter]This command launches Explorer, in a “single pane view. ”This command option is used to specify the drive or folder tobe opened by Explorer. The content of the view is the“subobject, ” for instance “e:”

• Explorer /select, subobject [Enter]This command launches Explorer, and specifies the initial fileor folder to be selected. The parent folder of the selected file(or folder) is opened.

• Explorer /root, object [Enter]This command launches Explorer. The display is initiallyopened to “object ”; however, you cannot navigate above this

root.

The best way to use these command switches is to use them from aDOS box, and decide the settings best for your installation. Then,modify the Explorer shortcut on the desktop. This is shown in thefollowing figure.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



30

This setting (in the “Target Edit box ”) launches Explorer, in a two-pane view with all drives collapsed. To create this specification,right click on the Explorer icon on the desktop. From the resulting“context menu, ” select “Properties. ” When the “Explorer Properties ”dialog is displayed, click on the “Shortcut ” tab. The desiredconfiguration switches can then be specified in the “Target Editbox. ”

File Associations:

When in Windows Explorer, double clicking on a data file typicallyinvokes the associated software application. For example, doubleclicking on a “.doc ” file usually invokes Microsoft Word, doubleclicking on a “._a” file will typically invoke CAESAR II . Thesedata file - software application associations are typically definedwhen the software is installed, but can also be defined in Explorer.Double clicking on a data file that does not have an associatedapplication brings up a dialog for you to choose the application toassociate with the data file. This is shown in the following figure.

Assume we double click on the UK.FRM file, for which there is noapplication associated. If we assume this is a text file, we canassociate NOTEPAD with the “.FRM ” suffix, for all subsequentdouble clicks, as shown in the figure above.

Explorer also provides the ability to remove data file - softwarapplication associations. This is accomplished by clicking on the[View] menu, followed by [Folder Options], then the [File Types]tab. This will produce a dialog showing the registered file types andthe application associated with them. Selecting a file type andclicking on the [Remove] button will remove the data file - softwarapplication association for the selected data file. This is shown for

the “.FRM ” file in the figure below.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



31

If using Windows NT, you can view these file associations at theCommand Prompt (i.e. a DOS box) by issuing the “assoc ” command.If the list is too long, you can always pipe it into the “more ”command.

CAESAR II Notices

Listed below are those errors & omissions in the CAESAR IIprogram that have been identified since the last newsletter. Thesecorrections are available for download from our website. Unlessotherwise stated, all of these changes and corrections are containedin the 000502 build of Version 4.20.

1) Static Analysis Setup Module: Corrected the wave plotroutines to properly handle the wave/current directions.

• Corrected a problem with wind data, where running dynamicsin a different units system could corrupt a user-definedelevation table. Fixed in 000512 build

2) Structural Input Module: Corrected a plotting problemwith the orientation of non-symmetric cross sections.

3) Dynamic Force/Stress Computation Module: Corrected amemory allocation problem.

4) Animation Module: Corrected a plotting problem with theorientation of models viewed along one of the orthogonalglobal axis.

• Corrected the data display in the “element viewer ” for time

history results.

5) Intergraph Interface: Corrected a problem accessing the4.20 material data base.

• Corrected the interpretation of nodes flagged as anchorpoints.

6) Miscellaneous Module: Corrected the equation for theflange factor F1.

• Corrected a units conversion problem. Fixed in 000509build.

7) Offshore DLL: Corrected a convergence problem with theStoke ’s wave theory.

8) Static Force/Stress Module: Corrected a problem generatingODBC output for load cases existing at only the “stress ” level.

9) PCF Interface: Corrected to prevent some rigid elementsfrom being interpreted as bends.

10) Piping Input Module: Corrected a “stack overflow ” conditionwith the “delta ” fields.

• Corrected a data association for input listings.

• Corrected a problem accessing the CADWorx database.Fixed in the 000509 build.

11) CADWorx Valve/Flange Data Base: Completely replacedthe CADWorx data directories to provide up-to-date data.

12) WRC107 Module: Corrected the “units conversion ” of the“pressure ” value for output reporting.

13) Static & Dynamic Output Modules: Corrected a unitsconversion error when generating input listings of concentratedforce data. Fixed in 000509 build.

TANK Notices

Listed below are those errors & omissions in the TANK programthat have been identified since the last newsletter. These correctionsare available for download from our website. Unless otherwisestated, all of these changes and corrections are contained in the000217 build.

1) Input Module: Corrected the handling of “user units files ”when located in the data directory instead of the \tank\systemdirectory. This problem was corrected in the 000217 build of Version 2.00

• Corrected a problem with the sizing scratchpad for the“diameter variation ” table. This problem was corrected inthe 000217 build of Version 2.00

• An incorrect date check was included in the initial releaseof Version 2.10. This problem was corrected in the 000605build of Version 2.10.

2) Solution Module: Corrected the determination of the “percentroof weight supported by the shell ” for supported cone roof tanks, supported by only a single center column. This problemwas corrected in the 000217 build of Version 2.00.

3) Error Check Module: The error checker in Version 2.10 didnot allow roofs to be turned off, according to the setting in theinput file. This problem was corrected in the 000605 build of Version 2.10.

4) Units Files: An error in the data for Pressure Loading in the2.10 units files caused incorrect roof live load input. Newunits files were generated for the build of 000614.

8/12/2019 V o l u m e 2 9 j u n e 2 0 0 0



12777 Jones Rd Suite 480 Tel: 281-890-4566 Web: www coade comCOADE Engineering Software

CodeCalc Notices

Listed below are those errors & omissions in the CodeCalc programthat have been identified since the last newsletter. These correctionsare available for download from our website.

1) Window Interactions:

• Memory issues (Issues arising out of the memory overwrite)in CodeCalc were fixed in subsequent builds (117 and315). This caused aborts for no apparent reason whileentering data.

• Addressed the unit conversion glitch for input in non-English units.

• Addressed the unit conversion of design temperature thatcaused incorrect references to material-allowable stressesin non-English units.

• Corrected the conversion of tubesheet corrosion allowanceinto user units.

• The program was not remembering the occurrence numberfor the material. This occurred for the new files created afterthe 117 build. This was addressed in the 501 build.

• Printing issues for windows 95/98 computers are resolved.

2) Floating head:

• For full-face gaskets, the program was computing theincorrect bolt loads (nonconservative error).

3) Horizontal vessel:

• During wind load application, in the calculation of the areafor transverse wind load, the head length for torisphericaland flat head was not converted to feet units. This has beencorrected now.

4) Rectangular vessel:

• For A4 vessel, the value of delta parameter was not beingconverted to non-English units. This only affected thedisplay and not the calculations.

5) Summary:

• Fixed the summary for UG-45, as it was erroneously printingout the message “UG-45 failed ” for the Manway openings.

6) WRC 107:

• Fixed a file sharing problem when more than one instanceof the same program was being run.

PVElite Notices

Listed below are those errors & omissions in the PVElite prograthat have been identified since the last newsletter. These correctionsare available for download from our website.

1) All of the notices listed in the CodeCalc section.

2) The program was using table 2a/2b allowable stresses forDivision 2 flanges when table 1a/1b should have been used.This error was introduced in version 3.6.

3) For BS-5500 lap joint flanges, the program was using all 4moments instead of only 1, thereby producing a conservativeflange design.

4) For horizontal vessels that had a "section type" stiffener entryin the saddle dialog, the program would compute a conservativesaddle weight.

5) In non-English units, the ANSI flange lookup would multiplysome dimensions by the conversion constant (whenunnecessary), producing a recognizable error. The graphicwould become noticeably distorted.

6) Corrected the computation of the axial force at the small/largeend junction of the cone for the horizontal vessel. The programwas computing a conservative solution.

7) For computing the MOI checks for the cone-cylinder junction,the program was considering total length of the attached shellinstead of the distance to the adjacent stiffener. Previousimplementation was usually a conservative one.

8) For large hub type nozzles, an adjustment was made to theappendix 1-7 routines for the proper computation and inertiacalculations when the vertical limit cut through or was abovethe bevel.

v o l u m e 2 9 j u n e 2 0 0 0

Documents