high performance engine analysis using hyperworks and permas

High Performance Engine Analysis using HyperWorks and PERMAS

08.11.2011 INTES GmbH, Schulze-Delitzsch-Str. 16, D-70565 Stuttgart www.intes.de 1

Michael Klein, INTES GmbH

High Performance Engine Analysis

Our guideline:• High performance for industrial usage• High performance for every day usage• No extra effort to use high performance

Required for high performance engine analysis:

AGENDA/CONTENTS

� Company – background in high performance computing

Required for high performance engine analysis:• Preprocessor interface with support of all features • High accuracy: only with more precise modeling

and correct simplifications the benefit from finer meshes is a more accurate result

• High performance features that result in shorter run times for a wide range of analysis

• Efficiency in postprocessing

INTES GmbH, Schulze-Delitzsch-Str. 16, D-70565 Stuttgart www.intes.de 2

� HyperMesh-PERMAS interface

� Bolt pretension Process modeling/loadhistoryContact

� New gasket-element solver

� PERMAS-HyperView interface� Conclusion

08.11.2011

Company

INTES• Privately held and independent Finite Element(FE) Technology company

• Founded in 1984 as spin-off of Stuttgart University• Offering own FE analysis software PERMAS,software development, and engineering services

• Based on long-term experience in thedevelopment of numerical FE methods

PERMAS FEA Software

Thermo-mechanical analysis:• Linear and non-linear static analysis• Contact analysis• Linear and non-linear heat transfer (steady-state and transient)

Vibroacoustic analysis:• Dynamic analysis (in time and frequency domain)• Fluid-structure acoustics• Spectral and random response analysis

Interfaces:• HyperMesh-PERMAS Interface since 2005 (developed by Altair)• PERMAS-HyperView Interface since 2005 (developed by INTES)• PERMAS-MotionSolve Interface (developed by INTES) 3

• High performance− Large models− Fast solvers− Parallelization

• Special algorithms− Contact Analysis− Gasket Analysis− Eigenvalues with MLDR− Fluid-structure coupling

• Productivity tools− Automatic part coupling and

incompatible meshes− Substructuring and submodelling− Direct interfaces

PERMAS FEA SoftwareGeneral purpose software to perform complex FE calculations in engineering

Full Set of Features for Engine Analysis

coupling of incompatible meshes

bolt pretension

nonlinear material behavior

gasket elements

press fit

08.11.2011 INTES GmbH, Schulze-Delitzsch-Str. 16, D-70565 Stuttgart www.intes.de 4

(transient) heat transfer analysis (result transfer)

contact analysis

nonlinear load history

integration analysis (static with subsequent dynamic analysis)

static analysis

Bolt Pretension

For bolt pretension a simplification in modeling is required, because bolt with all details like the thread raises analysis duration drastically.Simplification should always represent the mechanical behavior simpler, but correct.Example: classical and widely used pretension based on a surface inside the bolt.


Advantages:� Simple input� Exact definition of pretension force

Disadvantages:� Shortening of bolt in simulation instead of elongation in reality� Wrong direction of radial forces in thread area (radial tear instead of radial spreading)

08.11.2011

Bolt Pretension Applied to Thread

New method with bolt pretension applied to thread area.

Advantages:� Simple input� Exact definition of pretension force� Pretension in thread area


� Elongation of bolt, like in reality� Same/less effort for definition� Same analysis time� Better mechanics

Disadvantages:� Wrong direction of radial forces in thread area

08.11.2011


New method with bolt pretension applied to thread area.Simple input of optional alpha !

Additional advantages:� Forces in direction of flank angle� Radial spreading, like in reality


flank angle alpha

08.11.2011


New method with bolt pretension applied to thread area.Simple input of optional alpha !Simple input of optional pitch !

Additional advantages:� Forces in direction of flank angle


flank angle alpha

pitch

� Radial spreading, like in reality� Load path like in reality� Torque in bolt

08.11.2011

Pretension/Contact in HyperMesh

Complete range of all available contact and pretension definitions.

Input of all required and optional parameters like: • Optional alpha and• Optional pitch .


• Optional pitch .

08.11.2011

Process Modeling/Load History - Basics

• Complex analysis like engine analysis are characterized by an analysis process that consists of several steps.

• Typical steps are:– bolt pretension, – bolt force loss, – overclosure of parts, – friction relaxation,

− heat up,− cool down− firing cylinder and− …– friction relaxation,

• But with an excellent fine meshed model and a misty load sequence the results are misty!

• Precise tool for definition of load sequences is required for high performance analysis, if you want to get high accurate results.

• Simple error protective engineering method with good visual feedback for checking is used with PERMAS/Hypermesh:

– Load definition by function over load steps.


− …

08.11.2011

Load History - HyperMesh

• Example:Step 1: Bolt pretension force of 100%Step 2: Bolt force loss to 90% after

assemblyAll subsequent steps: Bolt lock


• HyperMesh:Definition and visual feedback in‘PERMAS LOADING Browser’

Advantages:� Simple input� Clear definition of load at any time

of the load history� Checkable (visual)

08.11.2011

FE-Model

Load History

Drawing

Assembling Operating load

operatingload

collar

washer

pretension

contact collar-washer

contact

shaft1 2 3 4 5


Frictional ContactDefinition

PretensionDefinition

Fixed

contactcollar-shaft

Easy description of nonlinear load history

Definition of contact-, load- and pretension-behavior

Description of behavior by function over load steps

08.11.2011

Contact Analysis

Contact is a general high performance feature of PE RMAS

• Ongoing development of unique method since 17 years

• Very efficient (for large models)

• Highly accurate (without artifical stiffness)

• Comfortable modeling (compatible and incompatible meshesof contact partners)

• Complete set of results

Sliced model


• Full parallelization for high performance

• Static and sliding friction

Frictional forces after assembly/pretension (step 1)

Contact status and frictional force vectors after full load (step 5)

08.11.2011

Gasket Elements - Modeling

engine-block

engine-head

gasket layer

Single gasket element details

physical gap → contact gap

physical behavior → material


One layer of engine gasket with beads

Physical gap is modeled with PERMAS contact gap- Best performance- Like reality, no stiffness

Physical behavior from measurement in main direction as PERMAS material input

- Pressure- Closure- Loading- Unloading- Plastic- Elastic

closure

pres

sure

08.11.2011

Contact Controlled Nonlinear Gasket

NLMATERIAL-iteration

plastic_mat

σ

ε

Workflow of analysisNLMATERIAL-iteration encloses CA-iteration→ during each NLMATERIAL-iteration a complete CA-iteration is done

Solution of:plastic materialnonlin. elasticitygasket material…

with iteration overstiffness matrix

shift gasket solution from NLMATERIAL-iteration to PERMAS’s best in class CA-iteration

saves time by shift from outer loop to inner loop

takes advantage of solution


CA-iteration

iteration ε

gasket_mat

closure

pres

sure

Solution of:contactnormal forcefriction forcefriction direction

pretension

with iteration overflexibility matrix

takes advantage of solutionin flexibility matrix

reduction of computation time

+ gasket material

08.11.2011

Contact Controlled Nonlinear GasketGasket is the Only Nonlinear Material

NLMATERIAL-iteration

Workflow of analysisNLMATERIAL-iteration not needed → only CA-iteration is done

Several engine analysis are done with linear materi al

Then the only nonlinearities are contact, pretensio n and gasket material (no linearization)

All nonlinearities are now solved by PERMAS contact iteration, with same/better result quality

NLMATERIAL-iteration is not needed

► Drastic reduction of computation time


CA-iteration

iteration

gasket_mat

closure

pres

sure

Solution of:contactnormal forcefriction forcefriction direction

pretension+ gasket material

with iteration overflexibility matrix

Drastic reduction of computation timeBreakthrough in engine analysis

STATIC

Still full nonlinear loading/unloading

08.11.2011

Benchmark Results Engine Nonlinear Model (plasticity, temperature dependency)

15

20

25

888.687 nodes516.809 elements (tet10, hexe8, x2stiff3)

2.498 gasket elements2.046 multipoint constraints

2.638.812 dofs24.694 ca dofs

11 steps: pretension, thermal load (hot/cold),

factor >2

elapsed run time [hours]

22.5

INTES GmbH, Schulze-Delitzsch-Str. 16, D-70565 Stuttgart www.intes.de 17INTES GmbH, Schulze-Delitzsch-Str. 16, D-70565 Stuttgart www.intes.de 17

0

5

10

PAXVILLE, 4 x Xeon MP Dual Core with 3,4 GHz, 26.000 MB memory, parallelization

11 steps: pretension, thermal load (hot/cold),firing, interference

11.0

22.5

old51 GB disc space

new GSKSOLV=CONTACT

51 GB disc space

Model of half a six-cylinder engine appears by courtesy of Ford Motor Company in Detroit, Michigan, USA

picture of a prequel engine model

08.11.2011

Benchmark Results Detroit Diesel EngineOnly Nonlinear Contact and Gasket

753.799 nodes942.497 elements (tet4, tet10, hexe8, x1stiff3)


2.209.978 dofs18.189 ca dofs

5 steps : pretension, thermal load,


2

2,5

3

3,5

factor 4.7

3.40



5 steps : pretension, thermal load,firing with different pressure levels

Model of half a six-cylinder Diesel engine appears by courtesy of Daimler Trucks North America in Detroit, Michigan, USA

0

0,5

1

1,5

2

0.72

3.40

old56 GB disc space

new GSKSOLV=CONTACT

29 GB disc space

48% saved

08.11.2011

Benchmark Results Big EngineOnly Nonlinear Contact and Gasket

9.412.073 nodes6.857.322 elements (tet4, tet10, penta6, hexe8)

1.639 gasket elements


40

50

60

Formerly huge pure linear models can now be calculated with full nonlinear gasket behavior.

?

?


BOXBORO, 4 x INTEL Xeon X7560 Octa Core with 2,27 GHz, 110.000 MB memory, parallelization


28.126.871 dofs51.232 ca dofs

6 steps : pretension, thermal load,firing of each cylinder

4 cylinder engine

0

10

20

30

3.2

new GSKSOLV=CONTACT

574 GB disc spaceold

? disc space

?

08.11.2011

Benchmark Results Engine 3Only Nonlinear Contact and Gasket

2.578.885 nodes1.476.012 elements (tet10, penta6, penta15,

hexe8, hexe20, tria3, quad4, x2stiff3)


7.669.010 dofs21.762 ca dofs


40

50

60

70

factor 20.8

68.3




5 cylinder enginewith attached parts

0

10

20

30

3.27

68.3

old137 GB disc space

new GSKSOLV=CONTACT

87 GB disc space

37% saved

08.11.2011

Turbocharger for Engine Analysis -Contact Status Files (CAS/CASO Files)

Contact status files serve for easy job recovery and/or considerable run-time acceleration of successive variants.

Contact status files save time by giving a suitable starting vector for contact iteration

CAS/CASO files can be saved every time, because they need very little disc space.Disc space example for Engine 3:


vector for contact iteration based on similarity.

With the new contact controlled nonlinear gasket analysis the gasket element solution is now part of CAS/CASO files.

Now engine analysis with gaskets considerably benefits from CAS/CASO files method.

Disc space example for Engine 3:a) save Database for restart: up to 87.000 MBb) save CAS/CASO files: about 2 MB

Typical Scenarios for CAS/CASO files

Simulation of variants

Restarts

08.11.2011

CAS/CASO Files – Reduction of Run Time


40

50

60

70

factor 20.8

68.3 1

1,5

2

2,5

3

3,5


Additionalfactor 1.8(factor 38overall)

1.8

3.27



2.578.885 nodes1.476.012 elements (tet10, penta6, penta15,

hexe8, hexe20, tria3, quad4, x2stiff3)


7.669.010 dofs21.762 ca dofs

0

10

20

30

3.27

68.3

old137 GB

1.80

PERMASdisc space

0

0,5

1


new87 G

1.8

new CONTACT+CASO88 GB disc space

new GSKSOLV=CONTACT

87 GB disc space

new+CASO88 GB

GSKSOLV=

08.11.2011

Postprocessing - HyperView

Direct binary interface from PERMAS to HyperView• PERMAS writes H3D• No file conversion required• Fast read in• Smallest possible file size• All PERMAS results available


E.g. contact results:• All time steps• All results, also model

checking results• Contour plot or• vector plot, …

08.11.2011



checking results• Contour plot or• Vector plot, …

INTES GmbH, Schulze-Delitzsch-Str. 16, D-70565 Stuttgart www.intes.de 2408.11.2011

Conclusion

• High performance engine analysis is useful:– if you can use it in your every day work and– if you have tools for all steps of the process that support high

performance analysis.

• HyperWorks and PERMAS together support all steps of high performance engine analysis.


high performance engine analysis.

Your benefit:�More variants in the same time or�Better results by finer models in the same time,� Leads to better understanding of the mechanical

behavior,� Leads to better products.

08.11.2011