Digimat for Automotive Applications

D I G I M A T f o r A u t o m o t i v e Mar ch 2011

Outline

Introduction

e-Xstream

DIGIMAT

Paradigm Shift: From CAE to Multi-Scale Modeling

Automotive Case Studies

Material Engineering

Structural Engineering

DIGIMAT outlook

Conclusions

Saturday, March 19, 2011 Copyright e-Xstream engineering, 2011 2

DIGIMAT

Is

The nonlinear multi-scale material modeling platform

Used by

Material Engineers

Structural Engineers

At

Material Suppliers

Tier 1 (Material Users/Any Industry)

OEM (Material Users/Any Industry)

For


Accurate & Efficient FEA of Composite Structures

Saturday, March 19, 2011 Copyright e-Xstream engineering, 2011

Developed by e-Xstream engineering :

- Provider of Simulation Software & Engineering Services

- 100% Focused on Advance Material Modeling

3

DIGIMAT Users

Material Suppliers

Composites

Plastics

Rubber

Other: Nano Materials, Hard Metals, Graphite, Ceramics,

Material Users (i.e. OEMs & Tier Suppliers) Automotive

Aerospace

Consumer (Electronics) Products

Defense

Industrial Products

Medical Devices

Other: Academic, R&D Institutes,


Key Benefits

Material Engineers:

To Understand & Optimize Material Behavior

To Support the Internal/External Users of the Materials

To Reduce Material Testing (Time & Cost)

To Improve Material Understanding

To Promote Material Usage

Structural Engineers

To Predict Structural Behavior

To improve FEA Predictivity & Accuracy

To Bridge the Gap between the Process & Structure

To Reduce Structure Prototyping & Testing (Time & Cost)


Automotive Composites

Matrix

Thermoplastics: PP, PA,

Thermosets: Epoxy,

Reinforcements

Fibers: Glass, Carbon, Natural,

Chopped (Short or long)

Distribution of Orientation (e.g. induced by injection)

Random

Continuous

UD

Woven

(Nano) Particles: Glass Bead, Mineral, Nano-Clay,

Manufacturing Processes

Molding: Injection, Compression (SMC, BMC)

RTM, vaRTM, RTM lite

Hand Layup


PARADIGM SHIFT

From CAE to Mu l t i -Sca le Mode l ing


Reinforced Thermoplastics


Standard FEA of a Reinforced Plastic Part


Element

Material

LS-DYNA

Test Data:

Tenstion, Compression, Shear,

Postulated Material Models:

Elastic, Elasto-Plastic,

Simplified behavior:

Isotropic, Homogeneous,

Temperature Angle

& Loading Strain-Rate

Process Material Structure


Material Processing

Moulding: Injection, Compression,...

Drapage, AFP, ...

Material Microsturcure

Chopped fibers

Continuous fibers: UD/Woven

Nano, ...

Material Chracteristics

Mechanical

Thermal

Electric, ... Part/Vehicle Performance

10


Structure Engineering

Digimat-MF, FE, MX

Digimat-MX, MAP, CAE

Injection: Part Filling & Fiber Orientation


Skin Core

Reinforced Thermoplastics


xx yy zz

xx

yy zz

12

Nonlinear Mutli-Scale Modeling


Element

Material

FE model

Test (or RE) Constituent Materials

Micromechanical Material Models

Stongly Couple to CAE

Accurate behavior

From FEA to Multi-Scale Modeling

14

Injection Molding

Drapage

Process FEA Material Testing & Modeling

Structural FEA

Note: This list is not exhaustive. The Logos are Trademarks or Registered Trademarks of their respective owners

Press Forming

Compression Molding

EXPRESS

CADPRESS

Source: Rhodia


Source: Rhodia Source: Campus

DIGIMAT: Workflow

Promising Material Candidates

Improved MF Modeling

Constituents Behavior

Composite behavior

Constituents Behavior

Strong,

2-Way Coupling

Copyright e-Xstream engineering, 2011 Saturday, March 19, 2011 15

Mate

ria

l En

gin

eerin

g

Str

uctu

re E

ng

ineerin

g

Automotive

Case Studies

MATERIAL ENGINEERING


Mechanical: Youngs Modulus fct Angle


4000

6000

8000

10000

12000

14000

16000

18000

0 20 40 60 80 100

angle ()

Mo

du

lus

(MP

a)

PA66+50w%GF, measured

PA66+50w%GF modelled with Digimat, modelled a2

PA66+50w%GF modelled with Digimat, measured a2

360

100 50

50

Tensile specimen

Thickness=2,1mm

gate

4000

5000

6000

7000

8000

9000

10000

11000

0 20 40 60 80 100

Angle ()

Modulu

s (M

Pa)

Digimat

Experience

Mechanical: Nonlinear Stress-Strain


360

100 50

50

Tensile specimen gate

0

20

40

60

80

100

120

140

160

180

200

0 0,02 0,04 0,06 0,08

True strain

Tru

e s

tre

ss (

MP

a) 0_exp

15_exp30_exp45_exp60_exp90_exp0 Digi15_Digi30_Digi45_Digi60_Digi90_Digi

19


Thermo-Mechanical: E & CTE as fct (T)

Temperature E11 Digi (MPa) E11 Exp (MPa) Diff. E22 Digi (MPa) E22 Exp (MPa) Diff.

29 C 12 031 11 803 -1.91% 7 480 7 223 -3.57%

120 C 4 073 3740 -8.93% 1 281 1 257 -1.96%

CTE Vs Temperature

0

0,00005

0,0001

0,00015

0,0002

0,00025

0 50 100 150 200 250

Temperature [C]

Th

erm

al e

xp

an

sio

n [

C-1

]

a11 Exp

a22 Exp

a33 Exp

a11 Digi

a22 Digi

a33 Digi

0.7928 0.0157 0.0525

0.0157 0.1789 0.0064

0.0525 0.0064 0.0283

Average Orientation Tensor

Courtesy of Solvay:

Material: IXEF 1002

Mechanical: UD Continuous Fiber CFRP


Materials : thermal conductivity (isotropic)

Kerimid 601: 0.23 W/mK

Al2O3 : 30.7 W/mK

2-phase Microstructure : Kerimid matrix with Al2O3 fibers

matrix : Kerimid

inclusions : Al2O3 fibers

volume fraction : from 0.0 to 0.4

AR = 6

orientation : random in xy-plane (Random2D)


Thermal: Thermal Conductivity

Materials : electrical conductivity (isotropic)

PE: 2.5 E-14 S/cm

Carbon : 50 S/cm (effective particle*)

Microstructure : 2-phase

matrix : PE

inclusions : Carbon

VF: 0 50%

AR: 1, 5.5 & 33

Orientation: Random3D

Saturday, March 19, 2011 Copyright e-Xstream engineering, 2011 23 * value obtained from composite with inclusion volume fraction 1.0 [Cai]

Electric : Electric Conductivity

Mechanical: Inter-Phase Debonding


Damage in the inter-phase

(macro strain 1%)

24


0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0 50 100 150 200

Pe

rco

lati

on

th

resh

old

Aspect ratio

Max. Percolation threshold vs. Aspect ratio StraightCurved -

Electric: Electrical percolation in CNT

25

STRUCTURE ENGINEERING



Technical Front End

DIGIMAT Material Model

PP-Matrix :

E= 1500 MPa

= 0.3

Fibres :

E = 72000 MPa

= 0.22 Volume Fraction = 19.46 % (40 % Weight Fraction)

Aspect ratio : 100 (Long Fibers)

Orientation : MOLDFLOW 5.1

FEA Model # Elements =12632 (S3R)

# Nodes = 6365

# DOF = 38190

Material : PP-LGF with DIGIMAT 1.6

Initial Stresses: MOLDFLOW 5.1 Courtesy of:

www.renault.com


Fixed

P3 : 20daN P1: 20daN

P2: 20daN

Structural Stiffness (MDA-Test)/Test

P1 -3.75%

P2 +8.07%

P3 -6.97% Courtesy of:

Technical Front End: Stiffness


5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Mode Number

Ein

ge

n F

req

ue

nc

y [

Hz]

Test

MDA Predictions

Courtesy of:

Technical Front End: Vibration

Copyright e-Xstream engineering, 2011 30

Airbag Container: Stiffness

Injection Molding Mesh: Number of nodes/Elements: 584,123/3,369,976

Structural Mesh: Number of nodes/Elements: 368,852/194,794

Material: AKULON K224-PG8 (40% Glass filled Impact Modied Polyamide)

Matrix: Impact Modified Polyamide type = elastoplastic Young Modulus = 2350 MPa Poisson Ratio = 0.38 Yield stress =30 MPa

Fibers: E-Glass Type = elastic

Density = 2.54 E+3 Young Modulus = 72 000 MPa Poisson Ratio = 0.22 Weight fraction = 40% Aspect ratio (L/D) = 20 Orientation = Injection Molding (.xml)

Courtesy of: AUTOLIV & DSM

RF @ Imposed D Experimental Force DIGIMAT to Abaqus Difference

Linear (to 10.5mm)

~ 6477 N 6203.49 N -4.2%

Cyclic (to 7mm)

~ 4765N 3949.18 N -17 %

Saturday, March 19, 2011

Quasi-Static/Monotonic: Elasto-Plastic DIGIMAT Material

Saturday, March 19, 2011 Copyright e-Xstream engineering, 2011 31 Courtesy of: AUTOLIV & DSM

Impact: Elasto-ViscoPlastic DIGIMAT Material

Saturday, March 19, 2011 Copyright e-Xstream engineering, 2011 32 Courtesy of: AUTOLIV & DSM

Airbag Container: Failure

Copyright e-Xstream engineering, 2011 Courtesy of :TRW & DSM

Akulon K224-PG6

Failure

Saturday, March 19, 2011 33

Airbag Container: Failure

Copyright e-Xstream engineering, 2011

Vo

n M

ises S

tress (

Pa)

t = 0.0088s t = 0.0084s t = 0.0054 s

Failure area

Courtesy of :TRW & DSM Saturday, March 19, 2011 34

Roof System Bearing: Local Stiffness


Roof System Bearing: Global Stiffness


Thermo-elasto-viscoplastic

PAGF oil pan

Reverse Engineering

Boundary conditions

Displacement / Force

Temperature load

Pressure

Creep

Oil Pan

Thermo-elasto-viscoplastic

PA/GF35 oil pan

Vastly different results

Isotropic: dmax = 4.1 mm

Anisotropic: dmax = 3.1 mm

Oil Pan: Anisotropic Creep

dISO

dANISO

Sun Roof Front Panel


Sun Roof Pannel: Stiffness


LC 2 LC 1

LC 3

LC 4

Lower B Pillar Insert

Part size : # 600 * 170 * 85 mm

Thickness : from 2 to 5.2 mm

Part weight : 2.4 kg

Material : PA6GF35


Dr. F. Braymand, L&L Products

Improved Physical Property Prediction of Short FRP (Session 5)

DIGIMAT Nonlinear Anisotropic Material


Lower B Pillar Insert: Modal Analysis


Lower B Pillar Insert: Crash & Failure


Bad failure

location

Good failure location

M.M.I Beam


Digimat-CAE: Impact Model (MMI Beam)


Mass of 18 kg

3 m/s for 5 gates

4,8 m/s for 2 gates

Failure at the same time

Digimat-CAE: Force & Failure (MMI Beam)


Failure in experimental and MMI

Failure with isotropic approach

Good correlation in force and failure

CPU Performance: Crash (Explicit)


CPU Performance: Quasi-Static (Implicit)


Technology Roadmap

DIGIMAT

Performance Thermal

Stiffness

Vibration

Crash

Electric

Creep

Fatigue

Failure

FEA

Structural/Implicit

Structural/Explicit

Multi-Scales

Macro

Micro

Nano

Processes

Injection Molding

Fiber Drapage

Auto. Fiber Plac

Materials

Plastics (LFT) Rubber

Hard Metals Nano

HoneyComb Carbon

UD & Woven composites

50 Saturday, March 19, 2011 Copyright e-Xstream engineering, 2011

DIGIMAT Dev Plan 2011

DIGIMAT 4.2 (Jul. 11)

Consolidate

Fast/Easy/Robust

FEA MSC: Marc

LSTC: Dyna Implicit

Materials

LFT

CFRP

Process: Drapage

Simulayt

Perfromance: Strength

Fatigue

nCode: DesignLife

LMS: VirtualLab Durability

Crash

DIGIMAT 4.3 (Dec. 11)

Consolidate

Fast/Easy/Robust

FEA MSC: Nastran

ANSYS OEM

Materials

LFT

CFRP

Process: Drapage

FiberSim

Perfromance: Strength

Fatigue

FEMFAT

Crash


Conclusions

Composite materials offer a great opportunity for weight and emissions reduction + many other advantages

There is no unique composite solution

Material

Thermoplastic vs. Thermosets

Carbon vs Glass vs

Chopped vs continuous fibers

Manufacturing Process

Injection vs. RTM vs. Compression vs. Drapage

The two main barriers to using composites

Price

Familiarity

Nonlinear Multi-Scale Modeling Technology can help

Understanding composite behavior Increase Familiarity

Optimizing composite design Reduce the material bill

Reducing the overall time & cost of developing composite materials & structures


Documents

Digimat for Automotive Applications