CRASH CAE IN THE ALL NEW VOLVO XC90 & SPA platformdocshare03.docshare.tips/files/26456/264561532.pdf2014-09-23 Material & welding 3 Material & welding NORDIC LS-DYNA USERS FORUM 2014

VOLVO XC90 & SPA platform

CRASH CAE IN THE ALL NEW

2014-09-23 NORDIC LS-DYNA USERS FORUM 2014 VOLVO CARS, SAFETY CENTRE, ANDERS SANDAHL 2

New challenges • Advanced materials with failure

• Multi-cell Al extrusion crash boxes

• Small overlap rating, IIHS

• Virtual sensor setting

• Zero complete car prototypes

• 6-7 CAE loops per car derivative

• Predict all relevant legal and rating load cases

• Optimized crash pulse

New CAE methods • Material failure with CrachFEM

• Spot weld failure with HAZ method

• Pre-clamped screw joints/bushings

• Ball joint pull-out/cam-out

• Rolling wheels

• Automated post processing

• Pre strained clips

2014-09-23 3

Material & welding

Material & welding Material & welding Material & welding

NORDIC LS-DYNA USERS FORUM 2014 VOLVO CARS, SAFETY CENTRE, ANDERS SANDAHL

2014-09-23 4

Remark:

Boron steel: 33%

Press hardened: 38%

XC90 Gen I

43%

34%

15%

7% 1%

XC90 Gen II 27%

9%

21% 3%

33%

6%

Very High Strength Steel

Mild Steel

High Strength Steel

Extra High Strength Steel

Ultra High Strength Steel

Aluminium

Body materials

Material & welding NORDIC LS-DYNA USERS FORUM 2014 VOLVO CARS, SAFETY CENTRE, ANDERS SANDAHL

5

Plasticity features of standard Crash CAE material models for metals:

• von Mises yield locus.

• Non-linear isotropic hardening.

• Strain rate dependency.

Additional plasticity features of GenYld:

• Plastic anisotropy (8 different yield loci).

• Kinematic and mixed hardening.

• Yield locus modifications (asymmetry, biaxial correction and shear waist).

Failure prediction criteria of CrachFEM:

• Ductile normal fracture (growth and coalescence of micro-voids).

• Ductile shear fracture (forming of shear bands).

• Instability (localized necking)

MF_GenYld+CrachFEM

2014-09-23


2014-09-23 6

6 6

Spot weld HAZ modelling Spotwelds in boron steel are

weaker then in other steel.

This is due to the Heat Affected

Zone (HAZ) around the weld.

Idea: semi-physical modelling: • Detailed, but not prohibitively detailed

• Four solids in SW

• One ring of elements (1.5 mm) in HAZ

• CrachFEM in base material and HAZ

• Modified properties in HAZ

• Prediction of spotweld failure and macro cracks


2014-09-23 7

Spot weld HAZ modelling

Material & welding

HAZ-welds

100% in the deformed

Part Of the body


2014-09-23 8

Model content/complexity

Model content/complexity NORDIC LS-DYNA USERS FORUM 2014 VOLVO CARS, SAFETY CENTRE, ANDERS SANDAHL

2014-09-23 9

Complete CAE model with interior

Interior model: • Dummies

• Seats & Belts

• Detailed Instrument panel model

• Carpets

• Driver and Passenger airbag

• IC (Inflatable Curtain)

• Knee airbag

• CrachFEM materials


Structure model: • CrachFEM materials

• Detailed HAZ welds

• Rolling wheels

• New powertrain models

• New chassis models

• Steering mechanics from

wheel to steering wheel

NORDIC LS-DYNA USERS FORUM 2014 VOLVO CARS, SAFETY CENTRE, ANDERS SANDAHL,

2014-09-23 10

New VEA-engines

4-cyl diesel & petrol

New front &rear chassis


Complete CAE model with interior

Extruded Al

Lower load path

NORDIC LS-DYNA USERS FORUM 2014 VOLVO CARS, SAFETY CENTRE, ANDERS SANDAHL,

2014-09-23 11

Designed

Around

You !

Interior and

Restraints

Model content/complexity NORDIC LS-DYNA USERS FORUM 2014 VOLVO CARS, SAFETY CENTRE, ANDERS SANDAHL,

2014-09-23 12

Interior and

Restraints

New seats with

whiplash and off road

protection

Model content/complexity NORDIC LS-DYNA USERS FORUM 2014 VOLVO CARS, SAFETY CENTRE, ANDERS SANDAHL,

2014-09-23 13

Interior and

Restraints

New Belts with

electric pretension to

keep you safe before

the crash occurs

Driver and passenger

airbags


2014-09-23 14

Interior and

Restraints

collapsible

steering column in X


2014-09-23 15

Interior and

Restraints

Interior Trim


2014-09-23 16

All together to keep

you safe


Interior and

Restraints


2014-09-23 17

more details in the Model • Important screw joints pre-clamped

during dynamic relaxation (*INITIAL_AXIAL_FORCE_BEAM)

• Screw joints with failure

• Most rubber bushings meshed in

detail (rubber meshed with solid

elements)

• Al-engine mounts meshed with solid

elements with failure

• Anisotropic CrachFEM material for

all Al-extruded parts


2014-09-23 18

Influence of rolling wheels

Not rolling


2014-09-23 19

Influence of rolling wheels

Rolling


Important for: • Barrier interaction

• Tyre to ground

interaction

• Total kinetic energy

≈ 2.8% higher

Remark: • *INITIAL_VELOCITY_GENERATION

More complex velocity initiation,

Improvement needed


2014-09-23 20

Detection of clip detach

Metallic and plastic clips

are modeled in detail, with

initial stress state, in order

to capture clip detaching at

right load.


Modeling of clips


2014-09-23 21


Debugging & starting a 10 milj+ model!

• Starting and debugging a 10 milj+ model is not an easy task

• Maximum 5 working days are dedicated for this in our time plans

• All subsystem models need debugging and test running prior to complete model test and debugging

• Debugging in pre/post processors and with scripts searching in d3hsp

• Debugging by running standstill simulations and main load cases

• Lots of manual debugging by experienced CAE engineers!

• Several versions of the model to test (Diesel, Petrol, LHD/RHD, 2WD/4WD...)

• Always remaining issues … there is no perfect model!


2014-09-23 22

correlation

Correlation NORDIC LS-DYNA USERS FORUM 2014 VOLVO CARS, SAFETY CENTRE, ANDERS SANDAHL

2014-09-23 23

CAE

Test

Improved pulse Correlation

LHD EUNCAP pulse correlation, Vehicle Body pulse

Correlation

Remark / Finding:

Global friction settings affects the result a lot!


Good pulse correlation - New CAE possibilities

2014-09-23 24


Good pulse correlation - CAE acc data has ben used TO start

Trigg logic settings earlier in project

2014-09-23 25


2014-09-23 26

small overlap

small overlap NORDIC LS-DYNA USERS FORUM 2014 VOLVO CARS, SAFETY CENTRE, ANDERS SANDAHL

2014-09-23 27

IIHS small overlap - a CAE Challenge

Failure need to be captured in: • All body materials

• All exterior materials, joints, clips

• All chassis parts

• All weld connections

• Most screw joints

• Detailed wheel model that can puncture & crack

40mph 25%


2014-09-23 28

CAE TEST


2014-09-23 29

CAE TEST


2014-09-23 30

Ball joint pull-out / cam-out

Ball Stud

Housing

Liner

Ring

small overlap

Correlated chassi joint separations

needed in order to improve

correlation in small overlap


2014-09-23

NORDIC LS-DYNA USERS FORUM 2014

31

Fpull-out

Fpush-out

Fpull-out

Fpush-out

M1M1

Test procedure

Requirement

F > Freq

Requirement

M1 > Mreq

Ball joint pull-out / cam-out correlation


2014-09-23 32

small overlap

Failure in the chassis, complete model Important: • No unphysical

stack up/edgeing

• All parts can fail

• Rim can crack

• Tyre can puncture

• Tyre can separate

from rim

-


2014-09-23 33

XC90 Car to car

small overlap

• Total number of elements: 17 200 000

• Simulation time: 250ms

• Number of CPU’s: 480

• Run time: 84h

• Number of elements reduced from 19 400 000 (two

complete cars) due to memory issues.


2014-09-23 34 Advanced post processing

Advanced post processing


2014-09-23 35

Post-processors with automatic generating functions

CAE/Test summary reports CAE/Test deeper analysis CAE/Test detailed reports

(embeded with animations, pictures, etc.)

Advanced post processing

Advanced post processing NORDIC LS-DYNA USERS FORUM 2014 VOLVO CARS, SAFETY CENTRE, ANDERS SANDAHL

2014-09-23 36 Cluster & load case adaption

Cluster & load case adaption


2014-09-23 37

HP ProLiant Blade Systems:

cs3: 640 Xeon Hex Core @ 2.80/2.93 GHz

cs5: 640 Xeon Octa Core @ 2.66 GHz

cs7: 640 Xeon Octa Core @ 2.66 GHz

Crash CAE batch system: 14080 cores

Some extra blades

44 Tb hard disk with backup

240 Tb hard disk without backup

2 CPUs per blade

16 blades per cabinet

3 cabinets per rack

7 racks in each server

Crach CAE Servers

Cluster & load case adaption NORDIC LS-DYNA USERS FORUM 2014 VOLVO CARS, SAFETY CENTRE, ANDERS SANDAHL

2014-09-23 38

Full Load case adapted

for side impact

Change

Shells - Type 2

- Type 16

7742983 2805950

4937033

4882369 3047172

1835197

-37%

+9%

-63%

Solids 1426718 754763 -47%

Total 9169701 5637132 -39%

Runtime (144 cores) 43.15h 22.07h -49%

Runtime efficiency

Full model

9.2M elements

Parts that has minor influence to the side impact

behavior, is replaced by rigid bodies with inertia

and mass and reduced subsystems

Load case adapted model

5.6M elements

Performance checked to give the

same response on interesting values

Cluster & load case adaption NORDIC LS-DYNA USERS FORUM 2014 VOLVO CARS, SAFETY CENTRE, ANDERS SANDAHL

2014-09-23 39

Head impact

Rollover / roof crush

Pedestrian

Side

Impact

Rear Impact

Low speed

Frontal impact

Large and Increasing number of loadcases

Large animals

summary NORDIC LS-DYNA USERS FORUM 2014 VOLVO CARS, SAFETY CENTRE, ANDERS SANDAHL

2014-09-23 40


2014-09-23 41

Summary

• Detailed modeling of connections is important (screw joints, welds, clips,

glue, bushings, ball joints)

• Increased need for failure predictions to get better correlated models also in

solid parts

• Running complete car crashes with full interior 10 milj+ models will be more

common in the future

• Model complexity and CAE ambitions has increased as fast as

computational capacity at VCC

• Advanced material models exist… but what about friction? (considerable influence !)

• This is only a glance of the CAE work performed in the SPA development the

last five years (42 CAE engineers, 10 nationalities , a great team!)


Thank you for your attention! Volvo Cars Safety Center:

Anders Sandahl

Johan Jergeus

Weijia Wu

Per-Anders Eggertsen

Domenico Macri Michelle Khoo

Oscar Centeno

Anders Eriksson

Emil Claesson

Mathias Retzlaff

Documents

CRASH CAE IN THE ALL NEW VOLVO XC90 & SPA platformdocshare03.docshare.tips/files/26456/264561532.pdf2014-09-23 Material & welding 3 Material & welding NORDIC LS-DYNA USERS FORUM 2014