precision design - esi group · success story product news casting corporateevents modified nhtsa...

PAMN E W S F R O M T H E V I R T U A L T R Y- O U T S P A C E

BMW is experimenting the H-Model to optimize

occupant protection in car crashes

success story

TALKISSUE

25

SP

RI

NG

20

04

w w w . e s i - g r o u p . c o m

EuroPAM 2004, pioneering concepts in Virtual Engineering

EASi-CRASH DYNA

focus on

product newscovers a wide andexpanding range of high-tech applicationsCFD-ACE+

Precision DesignPrecision Engineering

High Speed Performance

© 2003 IBM Corporation. IBM logo, eServer logos, POWER4 and pSeries are trademarks or registered trademarks of International Business Machines Corporation in the United States,

other countries, or both. Other company, product, and service names may be trademarks or service marks of others.

Empower simulation with powerful

IBM eServer pSeries

and Intellistation Power systems

ibm.com/servers/hp

Generating Performance with POWER4+™ Technology

editorial

Experience and expertise

How can we qualify the difference between expertise andexperience? Expertise is mostly a frozen experience, inother words, something that may quickly becomeobsolete. Expertise is a rear view mirror that allows us tosee what is happening behind us, but not ahead of us inour rapidly changing world. Hence, there is a need tofacilitate access to experience by documenting the bestavailable practices, while leaving engineers free to forgetheir own new experiences by running multiple "what-if"test cases.

How can this be made possible? Definitely not withphysical prototypes! Not only are they costly, but alsotime and energy consuming. Furthermore, they only allowyou to understand a fraction of what you want to know.When a component is physically crashed, what do youlearn about the safety coefficient, or where the ruptureactually started? In the same way, when a blank sheet isphysically stamped, what do you learn about the way thewrinkles started, the thinning process, or the spring-back? Very little! You just see the end results, but not theway these results were obtained.

Industry now needs to move away from the traditionaltrial-and-error methodology, which is supposed to placeincreased confidence in physical prototypes, and movetowards a new paradigm, called simulation-baseddesign, more favorable to innovation, more effective andless expensive. Simulation-based design means thatmany of the decisions affecting the final designconfiguration are taken as a result of computersimulations of the model's physical properties, leading tothe replacement of physical prototypes. This is not onlybecause a physical prototype cannot be used, but simplybecause, in some situations, it cannot exist! For example,in this edition of PAM-TALK, you will learn how BMW usessimulation-based design to get more insight into possiblehuman injuries in car crashes, which perfectly illustrates asituation where a physical prototype would be impossibleto create. You will also discover how Micronics hasdeveloped a "laboratory-on-a-card" using CFD-ACE+,the new advanced multiphysics software productacquired from CFDRC, and now part of ESI Group'sproduct portfolio.

Simulation-based design is no longer a technology forearly adopters. Simulation-based design brings theaffordable and proven means to accelerate theintroduction of innovative, high quality and more reliableproducts to the market today.

contents

ditorial

Alain de Rouvray Chairman and Chief Executive Officer, ESI Group

PAMTALK is issued quarterlyby ESI GroupExecutive Editor: Philippe BarzilaiEditor-in-Chief: Danièle Burdin-Dumont

ESI Group MarketingPARC D’AFFAIRES SILIC99 RUE DES SOLETS - BP 8011294513 Rungis Cedex - FRANCE Tel: +33 (0) 1 41 73 58 00Fax: +33 (0) 1 46 87 72 [email protected]

Design: Agence TETRAKTYS

ISSN 1635-866X

Impression : IMPRIMAIL - ZI des Sablons - 89100 SENSDépôt légal : Mai 04

S U C C E S S S T O R YBMW is experimenting the H-Model to optimize occupant protection in car crashes

PA R T N E R SExtreme simulation power in a Unix workstation

Upcoming events

P R O D U C T N E W SCFD-ACE+ covers a wide and expanding range of high-tech applications

PAM-CEM Solutions 2004 reduces physical tests in automotiveelectromagnetic compatibility

Focus on EASi-CRASH DYNA

C A S T I N GModeling of the Vacuum Arc Remelting process at BöhlerEdelstahl GmbH

ProCAST 2004.1, updated version extends performances for shape casting simulation

ESI Group's extended casting solutions on show

E V E N T SEuroPAM 2004, crossroads of innovations, information and pioneering concepts in Virtual Engineering

C O R P O R AT ECFD-CADalyzer recognized as one of the most innovative products in the field of design engineering

What’s new at www.esi-group.com?

All PAM and SYS products are trademarks of ESI Group. All otherproducts, names and companies referenced are trademarks orregistered trademarks of their respective owners. All text and imagesincluded in the articles are the copyright of the companies presentingtheir applications and simulations tasks.

Photo credits: Böhler Edelstahl GmbH, BMW Group, CFDRC, Citédes Sciences et de l’Industrie, EASi, Einzig Photographers Inc., HP,Injecta Druckguss AG, Micronics, Renault, ESI Group.

25ISSUE

47

12

16

18

S P R I N G 2 0 0 4

e ed

it

or

ia

l

3www.esi-group.com

8

success story4 www.esi-group.com

BMW is carrying out

scientific tests to study

the response of both

dummy and human

models in side impact

scenarios.

Current investigations

should greatly enhance

future safety design for

improved human

occupants’ security.

SUCCESS STORY PRODUCT NEWS CASTING CORPORATEEVENTS

types of finite elements and materialproperties to represent adequatemechanical behavior.

Then, the human model is used tocompare the effect of the barriergeometry on rib cage and pelvisloading for a sled-test configuration.

Lateral EuroNCAP Barrier Test

A validated PAM-CRASH finite elementvehicle model of a BMW is used tosimulate vehicle motion and intrusion ina standard side crash test scenario,with airbag, at 50 km/h (according tothe EuroNCAP barrier testing protocol).In a first step, a simulation with theEuroSID dummy model is performed toevaluate loads, accelerations and injuryvalues. In a second step, the dummymodel is replaced by the H-Model, withthe same output values as theinstrumentation channels in thephysical dummy (Fig.1). Ribdeflections, shear force andacceleration of the twelfth thoracic(T12) vertebra, and the acceleration ofthe pelvis, are specifically analyzed.

The behavior of the dummy and of theH-Model are comparable and show alot of similar responses, such as lowerrib deflection, T12 and pelvisacceleration (Fig.2, a, b, c). Some otherparameters are significantly lower withthe H-Model, such as upper andmiddle rib deflection, and T12 shearforce (Fig.2, d, e, f).

How to get moreinsight into possible humaninjuries in car crashes? Howto reproduce the complex

interaction of the human body with thevehicle to design safer restraintsystems? All of these issues are at theheart of BMW Group's research foroptimized protective equipment.

Full-scale crash tests use dummies toassess the likelihood of injury to ahuman occupant. Providing valuableinsight into crash dynamics andoccupant kinematics, digital simulationwith dummy models is commonly usedfor safety features design. But asdummies have to fulfill therequirements of technical measuringdevices, like durability andrepeatability, they do not alwaysadequately reproduce the complexityof the human body, and its interactionwith the vehicle.

In a joint effort to improve the biofidelityof design tools, BMW and the Institutefor Forensic Medicine in Munich areusing PAM-SAFE and finite elementmodels to investigate the differencesbetween the physical dummy and thehuman body.

BMW first evaluated the response of aFAT EuroSID I v.3.1 dummy model andcompared it to the the ESI Group H-Model 2003.1 for a complex impactconfiguration. The human model isdeveloped by ESI Group and IPS-I. Itcontains a deformable skeleton withthoracic and abdominal organs, flesh,skin, muscles, and ligaments. Hard andsoft tissues are modeled by various

BMW is experimenting the H-Model to optimize

occupant protection in car crashes

Glossary

■ FAT: Forschungsvereinigung Automobiltechnik

■ EuroSID: European Side Impact Dummy (SID)

■ EuroNCAP: European New Car AssessmentProgram

■ IPS-I: Integrated Professional SystemInternational

■ NHTSA: National Highway Traffic SafetyAdministration

Fig.1 : Simulation set-up with the EuroSID(high) and the H-Model (low)

success story 5www.esi-group.com


Upper and middle rib deflections inthe H-Model may be influenced by thebiofidelic arm position, more than inthe EuroSID (Fig.3 a and b).

Another reason for differences may bethe way rib deflections are measured,only in the lateral direction, whereas

the human thorax exhibits morecomplex deformations modes (Fig.4 aand b).

The higher T12 shear force in thedummy may be due to an artifact ofthe dummy design, in which a rigidthoracic spine is attached to a stiff

lumbar spine. In the H-Model, allvertebrae and in-between joints aremodeled, leading to a moreprogressive curvature (Fig.5 a and b).

Continuation on page 6

The behavior of the dummy andthe H-Model are comparable andshow a lot of similar responses, butthe H-Model gives more informationabout the injury mechanisms and thecomplex interaction of the humanwith the vehicle.

Fig.2 Output signalsversus time: red curve H-Model,blue curveEuroSID Model

Fig.5 :Comparison ofdummy spine

(left) and humanspine (right)

BMW's head of occupant simulation in side crashes and roll over

Fig.4 : Comparison of the middle rib deflection of the dummy with the complex 7th rib deformation of the H-Model

Fig.3 : Interaction between the airbag, the arm and the rib cage of the H-Model

a) initial, undeformed state b) after 37 ms

b) cut viewa) front view

a) lower rib deflection b) T12 acceleration c) pelvis acceleration

d) upper rib deflection e) middle rib deflection f) T12 shear force

‘ ‘ ‘ ‘

T12

success story6 www.esi-group.com


Modified NHTSA lateral sled test

Sled-test simulations are performedwith the H-Model according to amodified NHTSA procedure. Thebarrier has a mass of 1,000 kg and avelocity of 18 km/h. Two barriershapes are investigated: one flat wall,and one wall with an offset of 70 mmin the pelvis area. The kinematics ofthe H-Models with and without pelvisoffset are shown on Fig.6.

Comparison between the two shapesfor all 12 ribs (Fig.7) shows that thepelvis offset improves the ribdeflections and the viscous criterionwithout increasing the pelvis load.Lower rib deflection decreases by62%; upper rib deflection, which isinfluenced by the contact of theshoulder with the upper wall, isunchanged; viscous criteriondecreases by over 90%.

Initial simulations carried out with theH-Model in complex load cases, suchas side crash tests, yield promisingresults. According to the head ofoccupant simulation in side crashesand roll over at BMW: "We get moreunderstanding about the crash, thedummy and the human. The dummy isa reproducible measurement toolwhich cannot show any injury, whereasthe H-Model allows valuable insightinto possible injury mechanisms."

Conclusion

Optimizing occupant protection in sideimpact scenarios requires validinformation about occupant behavior.Resulting from long-term partnershipswith research institutions, laboratoriesand industries, ESI Group’s H-Modelhelps to provide realistic kinematics aswell as access to injury mechanismsand classical injury criteria.

Considering the complexity of thehuman body, future BMWinvestigations will focus on the furthervalidation of the H-Model, usinginjuries produced during welldocumented real-world accidents.

About BMW GroupThe BMW Group is a leading high standard German car manufacturer, representing 1.7%

of the worldwide automotive market, with more than 1.1 million vehicles sold. The BMW Group's

market position relies on its business strengths which are high-performance, safety, innovation

and precision. Its product line portfolio, falling into two main automotive sectors: cars and

motorcycles, inspires seduction, sport, power and harmony. The BMW Group also

owns the Mini and Rolls-Royce brands.

Fig.7 : Rib deflection (in mm, for each rib)with (blue) and without (green) pelvis offset

Fig.6 : H-Model behavior without(left) and with (right) pelvis offset Continued from page 5

partners 7www.esi-group.com

PARTNERS PRODUCT NEWS CASTING CORPORATEEVENTS

Flexibility and capacity to reactquickly with many sequentialruns are key factors in most ofstamping, casting, or forming

simulations. While large, shared SMPor cluster systems deliver the requiredcomputing power, engineers alsoneed personal dedicated systems thatcan combine reliability, graphiccapabilities and total availability.

Designed to address the mostdemanding technical workloads inautomotive, aerospace and electronicdesign enterprises, with 4X processor

The fender model contains 50,800elements and 27,858 simulationcycles.

Using the new platform helps reducecomputation times nearly by a factorof 4, as detailed below:

■ New HP C8000 (2 PA8800 cpus / 2GB RAM): 510 seconds !

■ Previous HP J6750 (2 PA8700 cpus / 2GB RAM): 2,027 seconds.

This PA-RISC workstation thusdelivers greater than clock rateperformance scaling, industry-leadinggraphics performance and a large 16GB memory footprint, all with renownedreliability and support from HP.

Find more information at:www.hp.com/workstations

Information and registration on www.esi-group.com

Date Event PlaceJune 7-12 BIEMH 2004 23rd Spanish Machine Tool Biennial Exhibition Bilbao (Spain)

June 12-15 108th Metalcasting Congress Largest annual meeting of metal-casters in the USA Rosement, Illinois (USA)

July 5-8 ICSV11 11th International Congress on Sound and Vibration St Petersburg (Russia)

July 12-14 Noise-Con 200420th national conference held by The Institute of Noise Control Baltimore, Maryland (USA)Engineering of the USA (INCE/USA)

August 22-28 Inter-Noise 200433rd International Congress and Exposition

Prague (Czech Republic)on Noise Control Engineering

ESI Group participates in the following events:

HP C8000 64-bitworkstation brings 2-way and 4-waycomputing power to the desktop

Extremesimulation

power in a Unix

workstation

and memory I/O bandwidth and 25%lower memory latency of previousgeneration PA-RISC workstations, thenewly available HP C8000 bringsleadership performance for traditionalUNIX® applications. It supports thelatest industry-leading AGP 8Xgraphics and can easily handle thecomplexities of large models, systemassemblies, design analysis andsimulations.

Reduced computation timesin real industrial test-case

As an example, a PAM-STAMPsimulation of a car front fender iscarried out to evaluate theperformance improvement.

New PA-RISC HP

workstation to enable

running large tests in

the minimal period of

time, directly from

engineers’ desk

product news www.esi-group.com

CFD-ACE+ covers awide and expandingrange of high-techapplications

Using CFD-ACE+allows us and ourcustomers to save bothtime and prototypeproduction costs for ourlab card products

Micronics Inc.Applied understanding of the sensitivity of parameters for product design optimization

CFD-ACE+ is a useful design tool inproviding custom-developed laboratory-on-a-card ("lab card") products. Micronics, Inc.has been using CFD-ACE+ to betterunderstand experimental data. Accordingto Dr. Fred Battrell, Micronics' VP ofOperations, "We find CFD-ACE+ especiallyuseful as a predictive tool of laminar flowproperties in the micro channels we devise on lab cards. This allows Micronics and its clients worldwideto save both time and prototype production costs."

Micronics' work is at the micro to picoliter level of volume control within its disposable lab cards thattypically are the size of a credit card. In addition to the built-in modeling capabilities of CFD-ACE+ fordetermining the desired channel flow regime and understanding the effects of surface tension, surfaceadsorption, binding, and reaction, the software's User Subroutines allows Micronics great flexibility inmodeling diverse phenomena. "With CFD-ACE+ we can model parallel streams in which viscositychanges with both position and time as multiple components in the fluid diffuse across the channel atdifferent rates."

About MicronicsBased in Redmond, Wash., Micronics is a leading developer of custom lab card devices for applications ranging fromon-card immunoassays, nucleic acid assays, protein crystallography, particle separation and mixing, and other analysesin the life sciences, genomics, proteomics, diagnostics, drug discovery and analytical chemistry markets.www.micronics.net

‘ ‘‘ ‘

With the integrationof major CFDRCsoftware products, ESIGroup is pioneering

promising new application areas. CFD-ACE+, the flagship advanced CFD and multiphysics software package allowsto solve the most challenging problemsinvolving fluid, thermal, chemical,biological, electrical or mechanicalphenomena.

Biomedical & biotechnologies

Today's modern device design requiresthe incorporation of complex physicalinteractions. Through CFD-ACE+simulations, designers canconceptualize, analyze and optimizethe performance of vascular devices;such as catheters, grafts, stents, filtersand blood pumps; simulate drugdelivery, test devices for biodiagnosticsand model complex physiologicalprocesses.

8

Custom-developed lab-on-a-cardsolutions for pharmaceutical, biotech,

diagnostic and reagent companies

CFD-ACE+ is used throughout the public

and private sectors to both model and optimize

fluid flow, fluid structure interaction and chemical

reactions in semiconductor, biotechnology

and nanotechnology, as well as general

mechanical designs

Performance simulation of a clot filterinserted into a blood vessel


product news 9www.esi-group.com

processing. The Plasma optioncombines plasma chemistry andtransport with electrophysics in aneasy-to-use, integrated environment fora wide range of semiconductorapplications, from low-pressure non-equilibrium to thermal atmosphericplasmas, all with 3D capability. CFD-ACE+ Plasma handles most types ofsemiconductor plasmas usingstructured and unstructured gridmethodologies in full 3D. It alsosimulates flow effects between gas flowand plasma transport. This moduleenables engineers to calculate the heattransfer and thermal balance of theentire plasma reactor as well as thedeformations and stresses of the waferand chamber. Finally, CFD-ACE+simulates electromagnetic powerdeposition, RF/DC (RadioFrequency/Direct Current) bias andplasma enhanced reactions for plasmasystems.

Fuel cells

Clean, quiet, reusable and efficient arewords used to describe fuel celltechnology as an alternative powersource in transportation, powergeneration and consumer electronics.CFD-ACE+ provides the idealenvironment to conceptualize, analyzeand optimize the fundamental fuel cellcomponents and systems. CFD-ACE+is successfully used to model ProtonExchange Membrane (PEMFC), SolidOxide (SOFC), Direct Methanol (DMFC)and Alkaline Fuel Cell (AFC). CFD-ACE+ is also used to design andoptimize reformers. The softwareproduct brings an adequate answer bymodeling the fundamental physics offuel cells including: flow, heat transfer,thermal stress, mass transfer, currenttransfer and electrochemistry in porousmedia.

Tailored toward specific disciplines,CFD-ACE+ addresses alsocombustion, propulsion, materials,defense, aerospace, automotive,chemical, electronics andenvironmental industries. Withadvanced physical models, CFD-ACE+provides powerful multiphysicssolutions to a wide variety oforganizations worldwide, helping themto increase their productivity throughreduced fabrication time and cost.

MEMS and microfluidics

Micro-Electro-Mechanical Systems(MEMS) is the integration of mechanicalelements, sensors, actuators, mirrors,and electronics on a common siliconsubstrate through microfabricationtechnology. MEMS and microfluidicsdevices, like integrated circuits can bemanufactured in high volume at lowcost and promise to revolutionizetelecommunications, biology andprecision tools by making possible therealization of complete systems-on-a-chip. CFD-ACE+ helps analyze, designand optimize BioMEMS, lab-on-a-chip,and microfluidic devices by rigorouslysimulating the complex interactingphysics (fluid flow, heat transfer,chemical reactions, electrokinetics,stress, etc.) that govern biochipperformance.

Semiconductor processes

Optimizing semiconductor processingrequires high fidelity three-dimensionalsimulations of heat and mass transportwith complex multi-step gas-phase andsurface reactions for a wide range ofsemiconductor reactor types.CFD-ACE+ provides accuraterepresentation of real world effects ofsemiconductor manufacturingequipment and processes for the threemajor markets of the semiconductormanufacturing industry. Equipmentmanufacturers, integrated devicemanufacturers and pure play foundriesare conducting CFD-ACE+ analyses forevery key aspect of the devicefabrication process.

Using CFD-ACE+, process engineerscan analyze the effect of keyparameters that determine the speedand quality of etching and depositionprocesses. Through the understandingof important characteristics, such asthermal uniformity and aspect ratios,they can assess the scalability ofprocesses and determine the impact ofeach process step. These capabilitieshelp save time and money bysignificantly reducing the need forphysical testing of fabricationprocesses and reactor prototypes.

Plasma

CFD-ACE+ allows users to simulate thebehavior of plasmas for semiconductor

Computational fluid dynamics and multiphysics solutions

CFD-ACE+: advanced CFD and multiphysics software forbio and microfluidics, semiconductors, plasma, fuel cells

CFD-FASTRAN: powerful software for high speed flows withmoving bodies and aerothermochemistry

CFD-VisCART: adaptive viscous, Cartesian mesh generationsystem for use with the CFD-ACE+ and CFD-FASTRAN flow solvers

CFD-CADalyzer: new CFD software enabling design engineers toperform virtual try-out early in the design cycle while alsoproviding a portal to CFD-ACE+ with multiphysics

3D simulation of liquid water

distribution in a PEM fuel cell

CFD-ACE+ processchamber model of a

Metal Oxide ChemicalVapor Deposition(MOCVD) Reactor

CFD-ACE+ 3Dsimulation of capacitivelycoupled plasmareactor


product news www.esi-group.com


10

PAM-CEM Solutions2 0 0 4 f e a t u r e s acomprehensive family ofsoftware for virtual testing of

complex electromagnetic phenomena.PAM-CEM Solutions 2004 analyzeselectromagnetic compatibility andinterference problems in a widefrequency range. PAM-CEM Solutionsincludes CRIPTE, for inducedphenomena on cable networks, andSYSMAGNA, for low frequencyanalysis.

PAM-CEM Solutions 2004 meetsautomakers’ requirements for a fullyrealistic EMS (ElectromagneticSusceptibility) analysis in the earlydesign stage, including simulation of3D radiated fields and induced effectson the vehicle cable networks. With theproliferation of complex on-boardelectronic equipment throughout thetransportation industry, controllingelectromagnetic disturbance is morecritical than ever to meetingperformance and security objectives.

“This new release is a realbreakthrough towards the deploymentof digital Electromagnetic Compatibility

(EMC) in the automotive industry. Onlya close collaboration between ESIGroup and leading car manufacturerssuch as Renault or Nissan could makeit happen”, says Jean-Claude Kedzia,PAM-CEM Solutions product manager.“PAM-CEM Solutions gives EMCexperts the ability to manage verysophisticated cable networks.Complex electromagnetic phenomenacan be investigated in depth very early,long before the first physical EMCprototype is available. The results ofsimulations powered by PAM-CEMSolutions provide a betterunderstanding of how the car willperform, helping engineers to evaluaterapidly various options in the vehicleelectrical design.”

With the new release, time domainradiated fields can be either calculatedthrough finite difference algorithms forfast evaluation or accurately computedusing advanced modeling with 3D finiteelement formalism. Both options areautomatically coupled with CRIPTE.Antenna radiation simulation is one ofthe main areas where PAM-CEMSolutions 2004 brings fullunderstanding of the phenomena.Several levels of accuracy are availableto the user for the analysis of wiredantennas. For example, the expert canselect a fast evaluation to optimize theperformance of traditional antennadevices and their location on-board,while an accurate simulation will berequired to analyze sophisticated rearor side window antennas, which are

known to be sensitive to their operatingenvironment.

Other new features of the 2004 releaseinclude a user-friendly environmentwith enhanced modeling capabilitiesfor on-board antennas and cablenetworks, from their placement in thevehicle to the specification of therelated electrical architecture.

PAM-CEM Solutions2004 reduces physicaltests in automotive

electromagneticcompatibilityNew version of the computational electromagneticsimulation software package gives engineers the ability to predict real world conditions in the early design stage

A V A I L A B I L I T Y

PAM-CEM Solutions 2004 is available on Unix workstations from HP, IBM, SGI, and Sun, as well as Linux hardware vendorsupported platforms

PAM-CEM SolutionsESI Group provides a completeEMC/EMI solution aiming atevaluating the electromagneticenvironment of fully equippedrealistic car models for very widefrequency range.

In addition PAM-CEM Solutions isable to serve as the virtuallaboratory for electroniccomponents and cable bundlescharacterized by reduced test set-up facilities, and to check the EMCcompliance of on-board equipmentand wiring systems.

The range includes:■ PAM-CEM for accurate 3D

analysis, ■ CRIPTE for cable networks,■ CEM3D for fast evaluation,■ SYSMAGNA for low frequency

characterization.

Simulation of the environment of a Renault vehicle under external

electromagnetic aggression

Focus on...

EASi-CRASH is a high performance CAE environment software for LS-DYNA, RADIOSS and PAM-CRASH users.

EASi-CRASH captures the process of model building, datasetpreparation, results evaluation against regulatory requirements anddesign comparisons into a single complete package.


product news 11www.esi-group.com

PAMTALK: LastDecember, ESI Groupacquired the intellectualproperty rights of EASi-CRASH simulationenvironments. How willEASi-CRASH take placewithin the currentportfolio?

ShivaKumara Shetty: With thisintegration, the company is openingits overall Virtual Try-Out Spaceenvironment. ESI Group now offers acommon user environment as well assimulation design and control tools forthe automotive industry, in particularin the area of safety.

EASi-CRASH gives the users fullaccess to complex and powerfulsimulation codes, supporting theirdedicated crash simulationcapabilities. In addition to PAM-CRASH, EASi-CRASH is the onlyenvironment solution which combinesboth pre and post-processing in aseamless package enabling acontinuous calculation loop. EASi-CRASH industry-proven simulationenvironments thus deliver extremeproductivity to the user for structuralcrash and coupling with rigid body forcrash synthesis simulations.

PAMTALK: Can you tellus more about EASi-CRASHDYNA's features speeding-up the process fromdataset preparation tocrashworthiness resultsexploitation?

ShivaKumara Shetty: The successof EASi-CRASH DYNA stays in itsability to quickly address the users’needs through the customizable TimeSaver programs.

For dataset preparation, engineersfollow a guided approach to quicklyand easily detect and correctintersection/penetration. They canalso use a smart tool to replace partsand resolve connections andreferences. This feature boostsproductivity gains by helpingengineers to quickly understand andsanitize the model. Other majoradvances lie in didactic tools for seatbelt creation and dummy positioningin just a few mouse click, as well aswelding capabilities to validate thewelding from CAD to FE data.

User-friendly EASi-CRASH data modelallows intelligent sorting and globalcontrol of CAD and CAE data. Aplugged "CHASE Iterations" functionhelps performing recurrent actions forboth test and CAE data. It generatesproductivity gains up to a factor 10.

To conclude, EASi-CRASH data modeland post-processor yield significanttime and cost savings with respect tocompetitive offer by simplifying datamanagement and automatic reporting.Overall, this CAE environmentsoftware roughly grants a 25% timesaving on solver data processing.

EASi-CRASH DYNA increases productivity through fast performance,essential functionality and extreme user-friendliness

Interview with ShivaKumara ShettyProduct Manager EASi-CRASH DYNA([email protected])

Key features■ Full capability to handle IGES, CATIA and NASTRAN files■ Powerful mesh editing features, such as automesh

and remesh

■ Complete support of LS-DYNA 970

■ LS-DYNA 970/MADYMO 6.X coupling

■ Part Replace, Penetration and intersection removal

■ Powerful welding utility

■ Simple dummy positioning and seat belt routing

■ Animation and Plotting ( EASi-PLOT) support■ Transfer of data from one model to another

...EASi-CRASH DYNA

casting www.esi-group.com

CALCOSOFT-2Dprovides for a betterunderstanding of thecoupled phenomenaoccurring in theremelting process

Modeling of the VacuumArc Remelting process at

Böhler Edelstahl GmbH

12

CALCOSOFT simulation of the VAR process

The difficulties involved in simulatingVacuum Arc Remelting (VAR)processes are directly linked to thewide range of physical and chemicalphenomena which occursimultaneously and are often coupledin such remelting processes.“CALCOSOFT brings the necessaryknowledge for a deep understanding ofthe VAR process,” adds C. Sommitsch.

A comprehensive digital simulationshould incorporate fluid flow, heat andmass transfer, electromagnetic effects,solidification (including microstructureprediction) and macro-segregation.The modeling of heat transfer, fluid flowand solidification, including grainstructure prediction, solid-statetransformation, hot tears, porosity andmacro-segregation, is already availablein CALCOSOFT-2D.

Moreover, CALCOSOFT-2D alsoincludes an induction heating modelwhich allows magnetic stirring to bemodeled. However, due to thegeometry of the VAR furnace and itspower supply, a new axisymmetricelectromagnetic solver which takesinto account both Lorentz's forces andOhm's law heating, was developed tosimulate the VAR process.

More than 250 steelgrades from BöhlerEdelstahl are used in theproduction of goods

which we use every day. They can befound, for example, in moulds for theproduction of plastic goods, in coldwork tool steels for punching, bendingand cutting applications, in hot worktool steel, in die casting or in specialmaterials for turbines, automotive andaircraft industry, etc.

Advanced technology for high quality products

Böhler Edelstahl combines the latestvacuum-melting technologies and arange of Electro Slag Remeltingfacilities enabling the manufacture ofmaterials with a high metallurgicaldegree of purity. Three VAR-furnaces,capable of producing ingots up to950 mm in diameter, are mainly usedfor the production of special steels andnickel-based alloys.

“We have been using CALCOSOFT-2Dfor two years to simulate solidificationand optimize the process,” saysChristof Sommitsch, Project Leader,Böhler Edelstahl GmbH. The companyconsiders CALCOSOFT-2D to be anefficient tool providing:

■ Better process understanding,

■ Process optimization and parameterstudies such as cooling, melt rateand geometry,

■ Increased material quality throughanalysis of macro and micro-segregations and non-metallicinclusions,

■ Better customer service thanks todetailed specifications andqualifications.


950 mm diameter ingot

Vacuum ArcFurnace

castingwww.esi-group.com

Analysis

The VAR process is characterized byan axisymmetric geometry, so allcalculations are carried out in a 2Daxisymmetric system. The model usedin the simulation contains the ingot andthe copper mould; the electrode andthe electric arc are not directlyconsidered. Heat flow, transport of thesolid phase, fluid flow and themagneto-dynamic effects in the pooldue to the melt current are taken intoaccount by the calculations.

Trials are carried out for three differentdimensions, a 310 mm, a 410 mm anda 510 mm diameter ingot, all made ofAlloy 718. The geometry of the mould,the electrode dimension and processparameters such as melt rate and meltcurrent correlate to those used forindustrial production. The total energycoming from the droplets and from theradiation of the electric arc isrepresented by a constant temperatureat the pool surface (given by theliquidus temperature and superheat),and a constant flow of materialaccording to the melt rate. Thesuperheat is estimated by multiplyingthe fraction of arc energy that goes intothe melt by the power of the arc perelectrode cross-section.

Starting from fictitious initial conditions,the heat balance of the system iscalculated until stationary conditionsare reached with a sufficiently highnumber of time steps. Transientprocess phases, such as changes inthe melt rate and phases of theprocess, which are transient by nature,for example hot topping or the startphase, are not taken into consideration.

Because of the shrinkage of thesolidifying material, a gap appearsbetween the ingot and the mould. Thegap formation, as a function of theingot height, can be calculated andequivalent heat transfer coefficients

between the ingot and cooling waterare derived as a function of the gapwidth.

CALCOSOFT helps to improve the quality of ingots

The main results obtained withCALCOSOFT-2D are: the temperaturedistribution, the distribution of thefraction of solid in the ingot and thefluid flow in the liquid pool.

The comparison between measuredand simulated pool profiles showsgood correlation for the pool profile ofthe 510 mm ingot.

The different flow regimes obtained forvarious ingot diameters can be relatedto the different acting forces. At the topof the pool, where the current density isvery high, the flow is mainly driven byLorentz forces which lead to the flowpattern observed. Further below thesurface, the current density decreasesand the flow regime is mainly driven bybuoyancy forces.

Based on these promising initialresults, Böhler Edelstahl GmbH nowplans to extend its simulation activitiesto microstructure and segregationpredictions. CALCOSOFT will also beused to analyze the simulation of thesolidification behavior of other alloys.Finally, the possibility of simulatingother production processes, inparticular the Electro Slag Remeltingprocess, is also being investigated.

Flow distribution for various ingot diameters (from 310 on theleft to 410, then 510 mm on the right)

Validation of pool profile: comparison of simulated and measured pool profile


13

Using CALCOSOFT-2D, we will be able toimprove the quality of our remelted ingots by anoptimization of the melt rate, the fill ratio, the coolingsystem and the current and voltage definitions.

‘ ‘‘ ‘

BÖHLER Edelstahl GmbH is one of the most important suppliersof high speed steel, tool steel and special materials worldwide.The company was founded in 1991 and is a 100% subsidiary ofthe BÖHLER UDDEHOLM AG group in Vienna.

Yearly producing 126,000 tons of special steels, BÖHLEREdelstahl concentrates on materials for highly demandingapplications in the aeronautics and aerospace sectors,automotive, energy, medicine, or in oil and chemical industries.Finally, not only the Austrian Mint but a lot of other renownedmints around the world are using the hardest BÖHLER steel toproduce billions of coins.

The latest vacuum-melting technology and an ever-increasingmetallurgical expertise guarantee the highest standard of quality– from melting to delivery.

More information on: http://www.bohler-edelstahl.at/

BöHLER Edelstahl GmbH

casting www.esi-group.com14

ProCAST 2004.1, updatedversion extends performances

for shape casting simulationProCAST’s new release brings new features and numerous

improvements in processing capabilities

Velocity magnitude and new particletracing display for an aluminum high

pressure die casting applicationProCAST 2004 version,released at the end of lastyear, featured a completelynew user interface offering a

fast and intuitive environment to theuser. Following that path, an updatedversion is now available, bringing evenmore new features in processingcapabilities and numerousimprovements in product performance.

ProCAST 2004.1 is the second releasedelivered by ESI Group since itsacquisition from UES Inc. ProCASTprecision solution addresses a widerange of casting processes andincludes capabilities for automaticmeshing, thermal and flow analysis,stress and deformation, microstructureanalysis and radiation effects. Extensivevalidations complying with ESI Group’sISO 9001 procedures have beenconducted to assess the reliability andconsistency of the simulation resultsobtained from the software product.

Major improvementsNumerous improvements have alsobeen made in the processingcapabilities of ProCAST. Limitations onmemory and file sizes have beenremoved with new memory allocationand input/output operationsmanagement.

Porosity models have been revisited forimproved accuracy and complementedwith up-to-date on-line documentation.Also, porosity predictions can now beactivated during a mold cyclinganalysis.

Based on extensive validations fromvarious industrial applications, the fillingalgorithms were further refined andparameter settings tuned so as toaccommodate for all metal flow regimesarising in lost foam, gravity, lowpressure and high pressure die casting.

With an efficient and intuitivevisualization environment, ProCAST2004.1 offers speed, accuracy andprocessing capabilities for a wide rangeof casting processes.

This updated version highlights ESIGroup’s strategy for providing highadded-value solutions to the castingindustry.

New featuresSeveral significant enhancements havebeen implemented in the 2004.1release. These new features will facilitatethe product customization allowingspecific user preferences to be definedfor material databases and icons.

Pre-processing includes new featuresfor:■ Definition of cycling analysis, ■ Automatic mesh optimization

including interface definitions,■ Easy set-up of inverse calculations

for material data and boundaryconditions,

■ Set-up and visualization of advancedmicrostructure predictions,

■ New filter permeability model.

Thermodynamic material databaseswere already available to calculate theenthalpy and solid fraction based on thealloy composition. With ProCAST2004.1, it is now possible to directlyobtain temperature dependent viscosityand density properties for aluminum,magnesium, titanium, nickel and castiron alloys. For aluminum alloys,conductivity calculations have alsobeen added.

Post-processing has also beensignificantly enhanced. Particle tracingis now available and directly computedby the solver for improved accuracy.Finally, a dynamic update of availablepost-processing steps has beenintroduced to visualize results while thecalculation is running.


AVA I L A B I L I T YProCAST 2004.1 is available on Windows NT and Windows 2000platforms, Linux hardware vendor supported platforms as well as

UNIX workstations from HP-Compaq, IBM, SGI and SUN.

Casting process simulation is now widely accepted as an importanttool in product design and process development to improve yieldand casting quality. ESI Group's casting portfolio includes:

■ ProCAST, CALCOSOFT, for fast and efficient modeling ofcontinuous casting processes and,

■ PAM-CAST/PAM-QUIKCAST, the finite difference softwarepackage for filling and solidification.

ESI Group’s casting solutions

Improved porosity predictions,respectively above 0.8%, 0.9%and 1% from top to bottom, for analuminum high pressure die casting application

Courtesy of Injecta Druckguss AG,Switzerland

casting 15www.esi-group.com

ESI Group’s extended castingsolutions on showEUROGUSS 2004: the entire process chain for pressure die casting in one place

At EUROGUSS 2004, theinternational trade fair forpressure die casting, ESIGroup introduced the

latest versions of its castingsolutions, with the support from HP.Many group managers anddecision-makers from the diecasting foundries and theautomotive industry visited thebooth.Outstanding demonstrations ofCALCOSOFT, ProCAST and PAM-CAST were performed; first steps ofnew business relations and projectswere outlined.

Engineering and simulationmethods captured interest from20% of visitors. Virtual simulation isnow occupying an establishedposition and is no longer aninnovation. The high pressure diecasting experts are increasinglyusing casting simulation tools notonly to optimize casting designs bydefect elimination but also to betterpredict fatigue life of the tooling.

EUROGUSS welcomed over 5,300visitors from 29 countries.Manufacturers of cast parts andcomponents, equipment manufacturersand suppliers, machinery manufacturersand process engineers were present inNuremberg, Germany. EUROGUSS2004 was the forum for the entire fieldof high pressure die casting inGermany and Central Europe.

Bringing together supply and demand,the 5th International Die Casting eventgathered 271 exhibitors on a 10,800sqm exhibition area.


EUROGUSS2004,

a growingexhibition

with impulses for a growing

market

A special three-day symposium inhonor of Prof. Wilfried Kurz wasorganized in March 2004, on the

occasion of the 133rd TMS annualmeeting, in Charlotte, North Carolina.Headquartered in the United States TheMinerals, Metals & Materials Society(TMS) is an organization thatencompasses the entire range ofmaterials and engineering.

Prof. W. Kurz officially retired from theSwiss Federal Institute of Technology(EPFL, Lausanne, Switzerland) in 2003at the age of 65.

Wilfried Kurz, is above all, known for hisbook Fundamentals of Solidification

and for many papers and ideas he hascontributed in the area of solidificationprocessing. Member of numerousmaterials societies, W. Kurz hasreceived many prestigious awards,including the Bruce Chalmers Award ofTMS in 1994 and the EuropeanMaterials Medal for his outstandingcontributions.

He was also, from the first stages, apassionate supporter for the creation ofCalcom SA in 1991 and a faithfulshareholder. Professor Kurz was also akey lecturer for twelve years in theannual solidification course co-organized by Calcom ESI, the ESIGroup casting business unit.

Calcom ESI was invited to present alecture at the TMS symposium. Thepaper on: "Introducing castingsimulation in industry: the stepstowards success" written by Drs M.Gremaud and M. Gäumann can befound at the following address: www.calcom.ch/News/Articles.html

The Calcom ESI team, having closelyinteracted with W. Kurz since 1984,wishes him a nice and active retirement.

Prof. Wilfried Kurz, a figure in the area of solidification

Professor Wilfried Kurz honored at TMS 2004


events16 www.esi-group.com

EuroPAM 2004venue: La Villette

Conference Centerin the heart of La

Cité des Sciences etde l'Industrie

Intense two-day conference with parallel sessionscovering the full scope of virtual testing and analysis

14th European conference and exhibition will be held October 11-13, in Paris, France

EuroPAM 2004, crossroads of innovations, information and pioneering concepts in Virtual Engineering

essential influence of material physicsand manufacturing processes inevaluating and predicting the "as built"product performance.

Dedicated user sessions on October 11

The first European Stamping UserConference, held on October 15, 2003,was a successful inaugural usermeeting with more than 60participants. Based on its success,this year's EuroPAM program has beenexpanded to include one daydedicated to specific user meetings.

The first day of the event, users will havethe opportunity to participate in one offour parallel user conferences on:

■ Crash and Occupant Safety

■ Stamping

■ Casting

■ Vibro-Acoustics.

These specific sessions are intended tolet users express their developmentneeds and to learn about the best in-class developments through dedicatede x p e r t p r e s e n t a t i o n s a n ddemonstrations.

High-level conferencefocused on digital simulationsoftware for prototyping andmanufacturing processes,

EuroPAM will welcome hundreds ofattendees next October. Gatheringfrom all over Europe, delegates willexchange ideas, discuss real worlduser cases, listen to various technicaland scientific presentations and sharethe latest visions and technologies indigital simulation.

Innovation through simulation

Client presentations and ESI Group’sexecutive workshops will draw anoverview of current stakes andinnovative process methodologies. Thelectures will provide more insight intoESI Group’s extended simulationportfolio now including computationalfluid dynamics and multiphysicssolutions from CFDRC. The strategicaddition of the EASi product portfoliowithin the overall Virtual Try-Out Spacesimulation environment will also belargely discussed. This powerful CAEsoftware solution will allow users tobuild the foundations of an open 3GPLM solution. Finally, new ESI GroupCAAV5 based products will take majorsteps toward a realistic PLM simulationin the VTOS, giving proper credit to the


State-of-the-art conferenceson October 12 and 13

First held in 1990, EuroPAM is theunique venue where the latestdevelopments in digital simulation arepresented, explained anddemonstrated by and to global industryleaders. EuroPAM 2004 will once againfeature an extensive programemphasizing the real-life simulationbehavior of industrial productssubjected to a wide range ofphenomena. The high-tech La Villettecongress center is the ideal place tolearn and debate on current and futureindustrial challenges.Recent progress in hardware andsystem developments will also bediscussed with the participation of HPCexperts from ESI Group and from theIndustry.

As in previous years, an exhibition areawill be opened during the two days ofthe congress to facilitate talks withhardware and systems experts and see

how HPC is making Virtual Engineeringmore affordable each year.

Join us to learn how today’s digitalprototyping is meeting industry’s mostpressing requirements to shortenproduct development cycles and tomanage increasing model complexity,variety and quality.

Please visit the EuroPAM website regularly:http://www.esi-group.com/EuroPAM2004/

Sharing experience with peers

corporate18 www.esi-group.com


CFD-CADalyzer recognized as oneof the most innovative products

in the field of design engineering

Newly acquired by ESIGroup, CFD-CADalyzerwas the winner of DesktopEngineering readers’ choice

award for December. Each issue, theAmerican MCAD magazine DesktopEngineering gives the readers’ choiceaward to the product that has receivedthe most reader interest.

Thanks to the recent acquisition ofCFDRC’s product division, ESI Grouphas enhanced its product portfoliowith new virtual engineering softwarei n c l u d i n g C F D - C A D a l y z e r,Computational Fluid Dynamics (CFD)software for design engineers, CFD-ACE+ for advanced CFD andmultiphysics simulation, CFD-FASTRAN, CFD software specificallydesigned for the aerospace industry,and CFD-VisCART for the generationof viscous, Cartesian meshes.

Mike Nieburg, business developmentmanager, ESI Group, said: “CFD-CADalyzer is a dramatically differentCFD simulation package. Combiningdesign and analysis, this product willcatalyze the increased focus on“getting it right the first time” at theearly conceptual design phase of

product development. Designengineers and analysts need not justfinite element analysis, but CFD tocreate winning products”.

"From my initial work with CFD-CADalyzer, I really like it. The ability towork with my 3D modeler and thengenerate a mesh with CADalyzer isoutstanding", said Craig Lanning,Professional Research Assistant at theCardiovascular Flow and ImagingResearch Laboratory at Denver’sChildren's Hospital.

CFD-CADalyzer for rapidsequential or parallel CFD simulations

CFD-CADalyzer provides anenhanced decision-making tool thatcan be used at the early conceptualand detailed design stages of productdevelopment. The product allowsparametric studies using the CADsystem for geometry changes, letting

designers assess the potentialperformance of multiple designvariants.

Main capabilities include modeling of3D fluid flow and heat transfer influids, solids and porous media withcomplex geometry; laminar orturbulent flow; and compressible andincompressible fluids. Other featuresinclude automatic mesh creation andcompatibility to CFD-ACE+ foradvanced multiphysics simulations.CFD-CADalyzer works with ACIS- orParasolid-based Mechanical CADapplications, such as AutodeskInventor, SolidEdge, SolidWorks andUnigraphics.

CFD-CADalyzer wins

Desktop Engineering

readers’ choice award

by enabling design

engineers to easily

simulate and optimize

fluid flow behavior

CFD-CADalyzer modeling the air flows around a race vehicle

Mike Nieburg,business developmentmanager, ESI Group,receives award fromTony Lockwood,editorial director forDesktop Engineering

corporate 19www.esi-group.com

ESI Group’s annual revenue2003 up 15% in real terms

ESI Group’s 2003 annual revenue reached 49 Million Euros, up15% in real terms, 22% at constant exchange rates. Alain deRouvray, Chairman and CEO of ESI Group, said: "What makes

revenue growth especially significant is that it is supported byincreased activity and the gradual adoption of 2G/3G solutions atOEMs and Tier 1 suppliers, particularly in the automotive industry.

Highlights of the year 2003/2004The year was marked by an excellent stability of the installed baseand a highly recurrent license revenue (88%). ■ The breakdown of annual revenue remained stable with 73% from

licenses and 27% from services.■ New Business increased by 12% (5% without acquisitions). New

Business accounted for 24% of license revenue.■ 79% of total turnover is generated abroad as follows: Europe

accounted for 50%, Asia/Pacific for 34% and America for 16%. ■ The major acquisitions made in 2002 and 2003 accounted for

15% of revenue growth and took part in the strengthening of thegroup's position on the American market.

Alain de Rouvray concluded: "Taking into account the impact ofsoftware acquisition costs write-offs and the slight delay in expectedservices’ sales particularly in the United States, the managementwill take the necessary steps to leverage the positive synergiesgenerated by the acquisitions in order to record an operating profitin the current fiscal year. Our recent acquisitions, however, positionus in new sectors, such as the biotechnologies and themicroelectromechanics (MEMs) industries, where tests areparticularly costly and delicate and the physical part is hard tocheck. Lastly, this year we expect to start marketing the first CAAV5solutions developed in partnership with Dassault Systèmes. All ofthese factors are part of the strengthening of ESI Group's leadershipand its utmost role in the adoption of PLM solutions."

Simplification of the organisational structureThe merger between ESI Group and ESI Software took the form of auniversal asset transfer, completed on April 30, 2004. The purposewas to simplify its administrative, legal and accounting organizationwhile optimizing flow and staff management. This simplification ispart of the ongoing process to rationalize costs and also complieswith ANVAR criteria for renewal of ESI Group's qualification as anInnovative Enterprise.

Renewal of innovative company awardThe French Innovation and Research Agency, ANVAR, has alreadyawarded ESI Group the label of "Innovative Enterprise" in recognitionof the company’s major R&D activities carried out since its creationto develop solutions with very high added value.

CFD-FASTRAN,computational fluid dynamics software from CFDRC

What’s new at www.esi-group.com?

T he layout of ESI Group’swebsite has just beenredesigned. The front page of the

site features a modern look and feel withgraphics and colors. Latest productreleases are advertised through a flashanimation with direct access tocorresponding pages. The productsection is organized by analysis field andsoftware solutions are easily navigated,thanks to directory pages with picturesand animations.

Among other improvements, the newsite now includes detailed informationabout EASi’s CAE software products.Dedicated e-flyers have been posted inparticular on EASi-SEAL, the integrateddesign-verification environment thatrapidly evaluates multiple seal systemand closure designs. Similarly, an e-flyeris available for download to give moreinsight on EASi-PROCESS, the

advanced technology for creating,automating and standardizing CAEprocesses.

The casting website now displays a newsection called 'casting news', availablefrom the introductory page. Please visitthese new pages to be updated on thelatest news from the casting line. Finally,the latest issues of ESI Group’selectronic newsletters, PAMTALK and“News on-line”, are posted at the bottomof the page for download or on-linesubscription.

Please come and visit the

ESI Group homepage frequently

to get the latest news.

If you have any suggestions,

please do not hesitate to use the

[email protected] e-mail address

or the contact web page.


HP Workstation c8000Extreme UNIX power, whisper quiet

The HP Workstation c8000 is a 64-bit workstation that brings2-way and 4-way computing power to the desktop, supportsthe latest industry-leading AGP 8X graphics and is compatiblewith existing HP-UX application environments.

The HP c8000 is designed to address the most demanding technical workloads in

automotive, aerospace and electronic design enterprises, with four times the processor

and memory I/O bandwidth and 25 percent lower memory latency of previous

generation PA-RISC workstations. It is ideal for handling the complexities of large

model, system assemblies, design analysis and simulations. The HP c8000 also

features breakthrough graphics performance with industry-standard AGP 8X graphics

on a UNIX workstation. No longer are you captive to antiquated, proprietary graphics

cards that trail industry innovation.

For more information, visit www.hp.com/workstations

HP Workstation c8000

2 or 4-way system using dual corePA-8800 processor modules at 900 MHz or 1.0 GHz with 32 MB of L2 cache

HP Scalable Processor Chipset zx1

HP-UX 11i TCOE or HP-UX 11i MTOE

Up to 16 GB PC2100 registeredECC DDR-266

ATI FireGL T2-128p and ATI FireGL X1-256pAGP-8X graphics

© 2004 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. The only warranties for HP products and services are set forth in the express warrantystatements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein.

Screen image courtesy of Dassault Systemes

IntroducingextremeUNIX power

precision design - esi group · success story product news casting corporateevents modified nhtsa...

Documents