1

Cody Godines Marc Villa Montero

F. Abdi (Ph.D) Harsh Baid (Ph. D)

S. DorMohammadi (Ph.D) M. Lee (Ph.D)

AlphaSTAR Corporation, Long Beach, CA 90804

ADVANCES IN REINFORCEMENT TECHNOLOGIES

SPE Automotive Composites Conference & Exhibition (ACCE),

6-8 September 2017 Detroit, Michigan

Multi-Scale Material Modeling and Progressive Failure Analysis of a Hybrid Composite Bumper

2

Agenda • Motivation • Methodology:

• Continuous Fiber, Chopped Fiber, FE Analysis Process Flowchart • De-Homogenized vs. Homogenized Approach

• Case Study: US Car FBCC Crush Test and Blind Prediction

• Multi-Scale Material Modeling SMC, Continuous, and Weave Architectures • Validation with Hat Crush Tubes

• Multi-Scale Progressive Failure Dynamic Analysis (MS-PFDA) L-D curve, contributing failure mechanisms

• Conclusion

3

AlphaSTAR Corporation Founded in 1989

Mission: Provide physics based composites simulation solutions and software Service industry and government for advanced composite parts/systems

Focus: Structural design using advanced simulation for Composites, Metals, Ceramics, Polymer, Hybrid

Industry Validated Software: Aerospace: Commercial Aircraft Certification by Analysis with Reduced Tests Automotive: Racing Industry, Composite Over-wrapped Pressure Vessels (COPV),

Hydrogen Tanks Infrastructure: Bridge, Wind & Energy, Oil & Gas 3-D Printing: Large Scale Additive Manufacturing

Awards & Publications: 2015 - R&D 100 Award, 204-NASA CAIB Award; 2001-US Senate/Tibbetts (SBA) Award; 2000 - R&D 100 Award; 2000-NASA Best of the 90’s Awar; 2000-NASA Turning Goals Into Reality; 1999-NASA Software of the Year Award; 230+ published papers and 4 Books

Located in: Long Beach, CA

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ASC family of tools provide advanced material modeling and structural analysis capability that is founded on multi-scale progressive failure analysis. All ASC products share a common GUI framework for seamless user interactivity.

ASC

ASC Products

5

AlphaSTAR takes on customers toughest challenges. Most projects are confidential. Those published include: Certification by Analysis Supplemented by Test Manufacturing Process Simulation

• 3D Printing/Additive Manufacturing Simulation • Filament Winding - COPV • Autoclave, RTM, VRTM

Advanced Design • Impact, Crash and / or Crush • Composite Fatigue • Residual Strength Determination • D&DT Analysis

Composite Analysis and Design • Material Characterization • A- & B-Basis Allowables (reduced tests) • Advanced Materials (ceramic, chopped, nano, polymer, hybrid) • Effect of Defects (tape layup, fiber placement, etc.)

AlphaSTAR’s Services & Expertise

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Executive Summary • Complete CAE Integration for both Material and Structure • Dehomogenized, Analytical Approach of Material Scales up to FE models • Test Verified Cases, Tutorials, Ready for CAE Users to make Quick Top Decisions

Continuous Fiber Static, LMA/AFRL

Fatigue, Void, 3d Architecture

0

5

10

15

20

25

30

35

40

45

1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07

Cycles to failure, Nf

Max

imum

Stre

ss L

evel

(ksi

)

high void content - DION 9800 resin with clay fillerlow void content - DION 9800 resin no clay fillerlow void content - Reichold 31638/31100 blendGENOA - 2% void contentGENOA - 10% void content

runout

Chopped, IM, CM, SMC Damage Mechanisms Tracked

3D Printed Structural Thermal Simulation

Creep Rupture Crack Growth

Web Based Structural Health Monitoring

Human Tissue Regeneration Modeling

A-B Basis Allowables

Ceramic/Engine Blade FOD Fatigue, Creep Environment (Humidity, Salt-Fog)

Complete Multi Scale Modeling

Certification By Analysis

7

Flow Process for MS-PFDA* Calibration, Verification, Validation, Predictions (Accreditation)

Objective: Match 4 Point Bend Test using lessons learn from previous steps Tests • Flexural 4 Point Bending test:

(1) 0/90-Weave (2) QI-Weave (3) Mix (UD-QI)

Outputs • Load-Displacement curves • Damage mechanisms • Stress and displacements

Objective: Match Crush test at two different energy levels and different layup configurations Layups

(1) 0/90 (2) QI (3) Mix (UD-QI)

Energies •0.715 kJ •2.27 kJ Outputs • Load-Time curves •Damage mechanisms •Deformed shape

Objective: Compare Un-notched MCQ with FEM Results and Test using 1-Element model FEM • LS-DYNA UMAT Compare • Un-notched MCQ Vs. FEM • FEM Vs. Test •Damage progression through the thickness Select FE • CPU • Less Mesh

MCQ Calibration

FEM Verification

Quasi Static MS-PFA

Validation

Dynamic MS-PFA Validation

Objective: Predict Resin, Fiber effective Properties, predict LMC Layups, Effect of defects

Tests Used Longitudinal Tension and

Compression, Transverse Tension and Compression, In-plane shear

1. UD 0°: 2. Cross Ply (UD 0/90) 3. Cross Ply Weave (PW 0/90) 4. QI Weave Predict Stress-Strain Curves, and Strain

limit for use in Validation

LS-DYNA UMAT

*Multi-Scale Progressive Failure Dynamic Analysis

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Building Block Approach Application to the Present Problem

Coupon Level

LS-DYNA UMAT

Material ModelingAnalytical: Calibration/Validation

FEM:Verification

5 ASTM Test

Simple Loading Component

FEM:Test Comparison

Static Test –4 Point Bending

Complex Loading Component

FEM:Test Comparison

Dynamic TestCrush Tube

Full Scale Testing (FST) – Structural

LevelFEM: Blind Prediction

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Methodology: De-Homogenized vs. Homogenized

Ref: Andrew Ritchey, Joshua Dustin, Jonathan Gosse and R. Byron Pipes, “Self-Consistent Micromechanical Enhancement of Continuous Fiber Composites”. Book Chapter ISBN 978-953-7619-X-X published by INTECH, Feb-2011.

Schematic View of De-Homogenized vs. Homogenized

• Multi-Scale Modeling of composite constituents • fiber, matrix, and interphase

• Manufacturing Effect of Defects • fiber waviness, agglomeration, interphase, • resin rich, void shape/size

• Fiber angle orientation Through-thickness • Design Parameters Saturation on stiffness/ strength :

•fiber length (limitation using homogenized method) •fiber shape

• Multi-Scale Nano-micro macro Damage evolution •Load re-distribution at every scale •Damage of individual constituents

De-homogenization Modeling Approach De-Homogenization Homogenization

* Courtesy of www.mscsoftware.com* Courtesy of www.mscsoftware.com

Architecture Homogenized

De-Homogenization Homogenization

* Courtesy of www.mscsoftware.com* Courtesy of www.mscsoftware.com

Architecture Homogenized

De-Homogenization Homogenization

* Courtesy of www.mscsoftware.com* Courtesy of www.mscsoftware.com

Architecture Homogenized

Homogenization

Numerical Approach Analytical Approach

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PFA takes full-scale FEM and breaks material properties down to microscopic level. Material properties are updated, reflecting any changes resulting from damage or crack

In-Depth Evaluation of Multi-scale Process

Vehicle Component Laminate 3D Fiber, Weave, Stitch

Lamina 2D Woven

Decomposition Traditional FEM Stops Here GENOA goes down to micro scale

Unit cell At node or element depending on solver

Sliced Unit Cell Micro Scale

FEM results decomposed to micro scale

Reduced properties propagate up to vehicle scale

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Technical Approach: Modeling Composite Failure Process Manufacturing Defects • Matrix Void Shape/Size/Distribution • Thickness Effect • Residual Stress • Fiber Waviness • Resin Rich

As-Build/As-Is Part

Manufacturing Cure Distortion • Matrix Shrinkage Vs. Temp/Pressure • Modulus/CTE Vs. Temp • Viscosity Vs. Temp

• Fiber Volume Vs. Temp • Thickness Vs. Temp

• Residual Stress

Residual Stress Distortion

Trans Laminar (σ or ε) • Matrix Crack Density • Matrix Failure (L/T)

• Tension • Compression • Shear

• Inter Phase • Fiber Failure (L/T)

• Long Compression • F/Matrix Delamination • Fiber Micro Buckling • Fiber Compression • Shear Kink Band

• Ply Failure • Tension • Compression • Shear

Damage Evolution

Propagation • Crack Path

•2-d •3-d

Interlaminar • Interlaminar Shear • Interlaminar Tension • Relative Rotation • Edge Delamination Combined*, HC**, Env***

Fracture Initiation • 0.005 inch • Requirement Size

Fracture Propagation • Gic • GIIc • Mixed Mode

Fracture Evolution

Residual Strength

Load

Displacement

GENOA

TEST

* Combined: Tsai-Wu, Tsai-Hill, Hashin, User defined criteria, Puck, SIFT, ** Honeycomb: Wrinkling, Crimpling, Dimpling, Intra-cell buckling, Core crushing. *** Environmental: Recession, Oxidation (Global, Discrete), aging, creep

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12

Material Characterization & Qualification (MCQ) Composites

MCQ Composites

Fiber Architecture

Manufacturing Defects, As-Built

Fiber Waviness Void Shape

In Plane Shear [0]

0102030405060708090

0.000 0.005 0.010 0.015 0.020 0.025

Shear Strain [mm/mm]

Shea

r Stre

ss [M

Pa]

TestMCQ

Material Non Linearity Input

A- & B-Basis Allowables Design Failure

Envelope

10

100

1,000

10,000

1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06 1.0E+07 1.0E+08

90T

90S

45T

45S

30T

30S

15T

15S

10T

10S

0T

0S

Stre

ngth

Cycles to Failure

Fatigue Life

VVR

FVR

WAVINESS THICKNESS

FMB_D11C

S 1 1

Test Data

Unnotched Compression [Ply-Level Scaling]

0100200300400500600700800900

0.000 0.005 0.010 0.015 0.020

Strain [mm/mm]

Str

ess

[MP

a]

t = 2mmt = 4mmt = 8mm

Parametric Carpet Plots

Thickness Effect

Probabilistic Sensitivity

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MCQ Chopped Fiber Flow Process

Particle Shape & Aspect Ratio

Matrix/Ply Nonlinearity Obtained from Material and Aligned layer non-linearity Input

Test Validation: Progressive Failure Design Failure Envelope Material Uncertainty

Chopped Mechanics

Tensor Orientation Through Thickness

Manufacturing Defects

Fiber Waviness Void Shape

Agglomeration Interphase

Vendor provided constituent Material Properties

Elastic Properties (1) Stiffness (2) Strength

0102030405060708090

100

0.00 0.01 0.02 0.03 0.04

Stre

ss [M

Pa]

Strain [mm/mm]

Test-Flow Test-45-Deg Test-Cross-FlowMCQ-Flow MCQ-45-Deg MCQ-Cross-Flow

SIG

YY

SIGXX

5 ASTM Tests Results In – Non Linearity Out

0.00.10.20.30.40.50.60.70.80.91.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Orie

ntat

ion

Normalized Thickness [z/H]

Test-A11 Test-A22 Test-A33MCQ-A11 MCQ-A22 MCQ-A33

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Summary of Cases

Crash Mode Mass (kg) Impact Velocity (m/s)

(S.D.) 1 Full Frontal 300.00 15.30 (0.24) 2 Frontal Offset 323.00 9.16 (1.98) 3 Frontal Pole 306.00 2.54 (0.16) 6 Frontal Angular 323.00 5.19 4 Low Speed Midpoint 302.30 4.56 (0.02) 5 Low Speed Quarter 326.40 4.21 (0.26)

Composite Layups Details Simulation Guidelines

-Six Models received with estimated mass and impact velocity -Models were almost ready to run and easy to use -Composite and SMC parts were identified

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Material Characterization and Qualification

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UD Material Calibration - Properties UD

Material Carbon/Epoxy Property Units Test MCQ % Error

E11 [GPa] 116 113.38 -2.26 E22 [GPa] 8.3 8.29 -0.12 E33 [GPa] 8.29 - G12 [GPa] 5.37 6.47 20.48 G13 [GPa] 6.47 - G23 [GPa] 2.5 - v12 [-] 0.324 0.323 -0.31 v13 [-] 0.32 - v23 [-] 0.56 -

S11T [MPa] 1683 1730.6 2.83 S11C [MPa] 687 698.5 1.67 S22T [MPa] 22.8 25.58 12.19 S22C [MPa] 113 135.8 20.18 S33T [MPa] - S33C [MPa] -

S12S (5%) [MPa] 83.9 73.8 -12.04 S13S [MPa] - S23S [MPa] - -

Effective Epoxy Matrix Material Properties Symbol Effective Units

Young's Modulus Em 4.698 [GPa] Poisson's Ratio νm 0.361 [-] Tension Strength SmT 32 [MPa] Compression Strength SmC 170 [MPa] Shear Strength SmS 100 [MPa]

Effective Fiber (Graphite) Fiber Material Properties Symbol Effective Units

Longitudinal Young's Modulus Ef11 210 [GPa] Transverse Young's Modulus Ef22 10.77 [GPa] Poisson's Ratio νf12 0.298 [-] Poisson's Ratio νf23 0.48 [-] Shear Modulus Gf12 36.98 [GPa] Shear Modulus Gf23 3.645 [GPa] Longitudinal Tension Strength Sf11T 2900 [MPa] Longitudinal Compression Strength Sf11C 1063.5 [MPa]

17

UD Material Calibration - Assumptions Layup Definition

Post-Damage Degradation Factors (Default)

Damage and Fracture Criteria

18

Uni Characterization Results ASTM Test MCQ-Composites Verification for UD layup

19

Plain Weave (PW) Material Calibration - Properties

Effective Fiber (Graphite) Fiber Material Properties Symbol Effective Units

Longitudinal Young's Modulus Ef11 218.05 [GPa] Transverse Young's Modulus Ef22 10.83 [GPa] Poisson's Ratio νf12 0.298 [-] Poisson's Ratio νf23 0.48 [-] Shear Modulus Gf12 36.67 [GPa] Shear Modulus Gf23 3.64 [GPa] Longitudinal Tension Strength Sf11T 4880.6 [MPa] Longitudinal Compression Strength Sf11C 2073.7 [MPa]

Effective Epoxy Matrix Material Properties Symbol Effective Units

Young's Modulus Em 3.758 [GPa] Poisson's Ratio νm 0.36 [-] Tension Strength SmT 33.76 [MPa] Compression Strength SmC 113.2 [MPa] Shear Strength SmS 104.76 [MPa]

Woven 0/90 Material Carbon/Epoxy

Property Units Test MCQ % Error E11 [GPa] 53.3 56.01 5.08 E22 [GPa] 53.1 55.7 4.90 E33 [GPa] 9.97 - G12 [GPa] 4.5 4.53 0.67 G13 [GPa] 3.3 - G23 [GPa] 3.39 - v12 [-] 0.055 0.041 -25.45 v13 [-] 0.54 - v23 [-] 0.55 -

S11T [MPa] 598 640.6 7.12 S11C [MPa] 619 587.1 -5.15 S22T [MPa] 764 705.8 -7.62 S22C [MPa] 415 486 17.11 S33T [MPa] - S33C [MPa] -

S12S (5%) [MPa] 110 71.97 -34.57 S13S [MPa] - S23S [MPa] - -

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Quasi Isotropic Weave Material Calibration - Assumptions

Braid 90

Braid 0

Layup Definition

Post-Damage Degradation Factors (Default)

Damage and Fracture Criteria *strain limit cuttoff for 11T (1.5e-2mm/mm)

Braid Card Definition

Braid 45 and -45

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LS-DYNA UMAT Verification – UMAT Card Details LS-DYNA UMAT Couples MCQ-Composites/GENOA micro-mechanics formulation

with FE Code

Laminate Definition same way as in LS-DYNA standalone

Fiber and Matrix mechanical properties and strain limits if needed

IPTYPE – Stress Redistribution Formulation control and Material Type (UD or Braid) ElemRm – Element Removal control by integration point failure IFAIL_D – GENOA Damage Criteria IFAIL_F – GENOA Fracture Criteria

Defects and post damage degradation factors

Fiber Waviness

Matrix Stress-Strain curve

22

LS-DYNA UMAT Verification – Plain Weave (0/90) Single Shell Element Verification using LS-DYNA/GENOA UMAT

23

SMC Material Modeling MCQ-Chopped inputs based on vendor’s and ASC’s databank

Calibrated Value for TR50S Properties

Chopped Composite Properties

Calibrated Value for Matrix Properties

MCQ-Chopped specific properties

24

SMC Material Modeling – MCQ Chopped to Composites Equivalent Continuous Fiber/Matrix from Chopped Fiber Data (Orientation and

Thickness) in order to model it in FEM

Step 1Test Validation using ply properties

Software: MCQ-ChoppedInput: Vendor provided fiber/matrix properties, fibergeometry and content, flow/cross-flow stress straincurves

Output: Aligned layer non linear ply properties,orientation angle through thickness andlongitudinal/transverse/shear stress-strain curves forvalidation

Step 2Test Validation using effective fiber/matrix

properties

Software: MCQ-CompositeInput: Aligned layer ply properties from MCQ-Chopped, fiber/matrix modulus, flow stress straincurves

Output: effective fiber/matrix non-linear propertiesand longitudinal/transverse/shear stress-straincurves for validation

MCQ-Chopped MCQ-Composites

Assumption: Same Damage/Fracture Criteria used MCQ-Composites effective properties

MCQ-Composites fictitious layup

25

Validation

26

GM Test - Simulation Results – QI Bolted Simulation shows comparable behavior with test data

Load vs. Time and integral of Load vs. Time Intrusion distance in simulation is 51.3 mm (~55mm in test) Energy absorption has good agreement with test Peak load 120kN simulation (90kN test)

0

20

40

60

80

100

120

140

-0.002 0.008 0.018 0.028 0.038

Load

(kN

)

Time (s)

QI - 2 Bolts Load vs. Time

QI 2 Bolts

ASC (LS-Dyna/GENOA)

Deformation Simulation <-> Test

Damage Genoa <-> Test

27

GM - Simulation vs. Test After Impact Through-the-thickness damages (Ply damages)

S11T S11C

S22T S22C

S12S S23S

S13S

0°

0°

0°

0°

0°

0°

90°

90°

90°

90°

90°

Damage Through the thickness at the Hat

S11T S11C

S22T S22C

S12S S23S

S13S

0°

0°

0°

0°

90°

90°

90°

90°

Damage Through the thickness at the Plate

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Predictions

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Blind Prediction Results for USAMP VMM Crush Cases Frontal Rigid

Frontal Offset Frontal Angular

Low Speed Quarter Load vs Displacment

Simulatin (Red) Test (Blue)

Simulation Curves have Shift in initial load due to Extraction Time

30

FBCC Crash Case Damage Investigation Results Load – Displacement and Damage Predictions – Full Frontal

All Damages Fiber Damage

Matrix Damage Delamination

Damages in Bumper

Fiber Damage Matrix Damage

Delamination

Damages in SMC

31

Conclusions •De-Homogenized Multi-Scale Modeling Methodology (Analytical)

• Effect of Defects: void shape/size/distribution, fiber waviness, resin rich • Fiber architecture • Failure Mechanisms: Translaminar, Interlaminar

•Conform to FE Standards

• Integrated with ABAQUS (Implicit, Explicit), LS-DYNA •Continuous Fiber

• Architecture Analytically Modeled

•Chopped Fiber • Material characterized Vs. limited Coupon tests • Fiber Content Vs. Fiber Length • Manufacturing Process: Injection Molding, Compression Molding, SMC, Mu Cell

•Service Loading Validation

• Static, Fatigue, Impact, Crush

• Methodology Allows Simulation of Entire Manufacturing Process, • Residual stress, Deformation • Delamination lamination initiation location • Contributing failure type • Location of damage and fracture