WS_2013_04_Advanced_Materials_Aerospace.pdf

Aerospace Industry Multi-Scale Modeling of Composite Materials & Structures Dr. Jan Seyfarth Product Manager Digimat April 2013

Copyright© e-Xstream engineering, 2013 2

Aerospace Industry A Very Short Introduction...

Digimat e-Xstream & Simulation Strategy Software

Materials Technology & Applications

From Materials to Structure Current Status and Ongoing Developments

Structures Technology & Applications

Summary

Aerospace Industry Multi-Scale Modeling of Composite Materials & Structures

Digimat

e-Xstream engineering Simulation Strategy

Nonlinear Multi-Scale Simulation Platform




Who are we...? A MSC Software Company! Team of ~30 persons PhDs (~65%) MS & BS Engineering (~ 25%) Marketing, Finance & Admin (~10%)

+ TBH in 2013

Material experts Micromechanics about...

COMPOSITES

Amsterdam, October 2012

e-Xstream engineering Digimat


What are we concerned about? Inter-dependencies in the Design of a Composite Part

e-Xstream engineering Digimat

Structural design

influences processing

Manufacturing sets

local microstructure

Local microstructure

sets material

properties

What do we do...? Multi-Scale! MICRO Material

MACRO Dumbbell Part

System Copyright© e-Xstream engineering, 2013 6

Micro- structure Material model

Part performance

Characterization

Process

System level

Simulation Strategy Digimat


Material Related Design Challenges Manage Material Data Generate Data (Cost & Time of Test) Manage, Trace, Protect (IP) Comply (Regulation)

Model (composite) Materials, Part & Systems Nonlinearity: Progressive damage & failure Anisotropy Heterogeneity Process dependency

Use The optimal mix of material The Material(s) as a design parameter to innovate The optimal manufacturing process

Simulation Strategy Digimat

Nonlinear Multiscale Modeling Platform

8 Copyright© e-Xstream engineering, 2013

Nonlinear Multi-Scale Simulation Platform Digimat

Performance Stiffness Failure Fatigue

Technology

Linear/Nonlinear Mean Field/FEA Micro/Hybrid


Nonlinear Multiscale Modeling Platform Holistic modeling Materials

Chopped Fibers: Short/Long Continuous Fibers Fillers

Physics

(Thermo-) Mechanical Thermal Conductivity Electric Conductivity

Manufacturing

Injection Compression Draping Fiber placement MuCell®


Nonlinear Multiscale Modeling Platform MICRO Virtual Material

MACRO Data management Reverse Engineering FEA Interfaces Mapping


Material Engineering

Structural Engineering


Interfaces to MSC Nastran SOL 101 - linear Weak coupling [Nastran material card used] Including SOL 103 for vibration Including SOL 105 for buckling

SOL 400 - nonlinear Implicit Strong coupling [Digimat user subroutine]

SOL 700 - nonlinear Explicit Strong coupling [Digimat user subroutine]


Available in 4.4.1

Specification phase

Under development


Materials

Composites

Materials Engineering Applications




A Vast Mix of Different Materials Metal (Alloys) Aluminium / Magnesium Molybdenum / Titanium / Tungsten

Reinforced Plastics Thermoplastics + Carbon fibers Epoxy + Glass / Carbon / Aramid fibers

Ceramics Titanium + SiC fibers

Composites Materials

Complex structures Pores

Stacking Weaving

Structure / Orientation

Random

Performance (Stiffness, failure, fatigue, ...) Anisotropy

Digimat-FE Fast & Efficient Prediction of Composite Material Properties


Materials Engineering Materials

UD Composites Defects & influence of processing ISEMP Integrative Simulation and Engineering of Materials and Processes » Aims at the simulation of material details and not only the macroscopic overall properties

» Aims at considering manufacturing process by the simulation » Uses commercially available software tools

CHALLENGE

Processing of CFRP results in residual stresses in the material Residual stresses lead to micro-damage & failure of CFRP Goal is to simulate residual stresses of a carbon fiber composite material at the micro scale with realistic topology


Applications Materials

UD Composites Defects & influence of processing E.g. already generated in the material during processing


Segmentation

Matrix enrichment

Pores

Delamination


UD Composites RVE Generation Periodic boundary conditions Enhanced flexibility 45° orientation » And other...



UD Composites RVE Generation Fibers Stochastic Intersection with » Matrix » Voids

Voids Stochastic Complex shapes Clustering, control over » Position » Shape » Orientation


[ 0° / 90° ]

fibers intersecting voids

complex shapes


UD Composites Curing effects Replacement experiment: Shrinkage due to temperature decrease



UD Composites Curing effects Delamination due to change in orientation



UD Composites Curing effects Crack propagation due to stochastic distribution of fibers



Strategic Simulation Tool Digimat Recommended tool for investigations


DIGIMAT enables us to perform in depth studies of complex and realistic

microstructures. As an invest into the future we base our simulation approach on the

DIGIMAT software, both for our research and the education of a new generation of

simulation engineers who will be experts in the modeling of materials.

Prof. Vasily Ploshikhin, Airbus endowed chair for Integrative Simulation and

Engineering of Materials and Processes (www.isemp.de)


Sandwich Panels

Micross - Stand-Alone Digimat Module Input Data @ micro and/or macro scale Fast Solution in less than 10 minutes Loading 3-Point & 4-Point Bending In-Plane Shear

Tuesday, 23 April 2013 23


Micross

Stand-alone module Definition of honeycomb core Definition of skin plies



Micross

Stand-alone module Visualization of results Failure indicators Skins: max. stress, Tsai-Wu, Tsai-Hill, Azzi-Tsai-Hill Core: shear, compression



From Materials to Structure

Critical Development Phase Materials Engineering

Current Status Ongoing Developments



Digimat-MF Fast & Efficient Prediction of Composite Material Properties


Output

Homogenization

DIGIMAT material model sensitive to composite microstructure

State-of-the-art homogenization methods

Per-phase material properties + microstructure information

Input

ar w [%]

matrix

filler

Materials Engineering From Materials to Structure

Digimat-MX Material eXchange & Reverse Engineering


Reverse Engineering

Input

Output

Calibrated DIGIMAT Material Model, stored in database and ready to be shared and used

Calibration of DIGIMAT models based on experimental data

Experimental data, DIGIMAT material models stored in database

Materials Engineering From Materials to Structure

Multi-Scale Approach Top Down | Reverse Engineering

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Critical Development Phase From Materials to Structure

Copyright© e-Xstream engineering, 2013

Multi-Scale Approach Bottom Up | Prediction of performance

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Critical Development Phase From Materials to Structure


Material Models - Standart (Thermo-) Elastic (Thermo-) Elastoplastic (Thermo-) Viscoelastic (Thermo-) Elasto-Viscoplastic

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f(T)

TEMPERATURE

f( )

STRAIN RATES

High strain rates Creep

f(OT) ANISOTROPY

Current Status From Materials to Structure


Material Models Advanced (Thermal) Creep Viscoelasticity Elasto-Viscoplasticity

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time

aligned

VE Matrix Composite

TVE Matrix Composite G0, K0 and CTE Constant

TVE Matrix Composite G0 =G0 0 = K0



Stiffness Eshelby approach for UD & woven composites Mean field homogenization Glass fibers isotropic Carbon fibers transversely isotropic

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Stiffness UD Composites RVE definition Layered microstructure

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Stiffness Failure


Stiffness Woven Composites - Basic model Superposition of fibers

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Stiffness Woven Composites - Advanced model Realistic woven structure

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yarn definition

woven modeler



Stiffness Woven Composites - Advanced model

Realistic woven structure

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visualization & property computation



Stiffness Virtual testing Stress & strain Tension & compression Creep & relaxation


uniaxial

shear

biaxial


Stiffness Input / Definition Epoxy matrix Density Isotropic elastic » modulus » Poisson ratio

Carbon fibers Density Transversely isotropic elastic » In-plane modulus » Axial modulus » In-plane Poisson ratio » Transverse Poisson ratio » Transverse shear modulus



ksi

t/mm3

ksi

t/mm3

Stiffness Input / Definition Ply Microstructure » Continuous fiber » Volume fraction of fibers: 61%

Laminate Stacking sequence » 3 different laminates Computation of » Laminate

» Stress response » Engineering properties

» Ply » Engineering properties

» Per-phase » Stress response



10/30/60 Laminate 1

60/30/10 Laminate 2

10/40/50 Laminate 3

Stiffness Output Laminate Stress response



11

Stiffness Output Laminate Stiffness matrix » In coordinate system of the RVE » Tensile direction: 11 » Orthotropic



Laminate 1 10/30/60

Laminate 2 60/30/10

Laminate 3 10/40/50

11

Stiffness Output Ply level Engineering constants » In coordinate system of the ply » Tensile direction: x » Unique for all three laminates



Lamina Angle 0° 45° 90°

Young Modulus (ksi)

Axial (along x-‐axis) 23.044 2.139 1.318

Transverse (along y-‐axis) 1.318 2.139 23.044

Stiffness Output Matrix level Microscopic properties » Stress 11 vs. Strain 11 [ksi] Per ply information » Different stresses ( ) & strains are reached » Dependent on the ply and sensitive to changes in the laminate design



imposed strain imposed strain imposed strain

0° 45° 90°

matrix strain matrix strain matrix strain

11

Stiffness Output Fiber level Microscopic properties » Stress 11 vs. Strain 11 [ksi] Per ply information » Dependent on the ply and sensitive to changes in the laminate design



imposed strain imposed strain imposed strain fiber strain fiber strain fiber strain

11

0° 45° 90°

Stiffness Coupled Analysis



Stiffness Coupled Analysis Global Response Laminate level Force / displacement curve » Digimat-MF Fraction of a second to solve micromechanics » Nastran Minutes for FEA analysis



Stiffness Coupled Analysis Local Response Ply level Macroscopic properties in each ply » Max. Princ. Stress [ksi] » Influence of the hole on local behavior



Laminate 1 10/30/60

Laminate 2 60/30/10

Laminate 3 10/40/50

Failure Matrix strain per ply Differs from macroscopic strain Input for unique strain based failure criteria

49


0°

45°

90°

-45°Orientation in ply

No matrix failure in 0° ply Average matrix strain in other plies for failure of the composite

Matrix Macroscopic


Failure Per ply definition Derived from microstructure Stress in fibers / strain in matrix



Progressive Failure Analysis Explicit solver Element deletion triggered by Stress in fibers / strain in matrix


Fiber failure


failureFibers.avi

Progressive Failure Analysis Validation of stiffness & failure Predictive modeling


RE on ply level of plain specimen Prediction of performance of open whole specimen


Progressive Failure Analysis The idea Feed the indicator, control stiffness & failure...


Ongoing Developments From Materials to Structure

Indicator

Matrix Strain

Transverse tensile

Fibers Stress Tension

Compression

Matrix stresses & strains

Fibers stresses & strains

Composite stresses & strains

Pre-Failure

Stiffness Reduction Damage controled by failure indicator

Failure

Element Deletion Final composite failure controled by critical damage

Progressive Failure Analysis Preliminary results 2013/02 release



Partial failure

No failure

Complete failure

Progressive Failure Analysis Preliminary results 2013/02 release Stiffness degradation Failure

55



Deformation: d11 & d22 Element deletion: progressive & classical

LAM_R&D_ProgressiveFailure_Progfail+D11-D22.avi

Structures

Structural Engineering

Applications



Short Fiber Reinforcement


Structural Engineering Structures

fibers

failure

ANISO

Measurements / curves

Process Simulation Orientation data on processing mesh

FEA Structural analysis

Structural mesh

Mapping

Anisotropic (non)linear

Material Model

ISO

Short Fiber Reinforcement Fittings Turbine parts



UD & Woven

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Measurements / curves

FEA Structural analysis

Anisotropic (non)linear

Material Model


UD

Woven

Draping Warp/weft angles


Summary




Summary Materials

In-depth study of a broad range of materials & performances SFRP, UD & woven composites, hard metals, ceramics, nano composites Complex RVEs micro stresses & strains (Thermo-)Mechanical, thermal & electrical conductivity

From Materials to Structure

Material property evaluation Screening / Selection / Specification / Allowables

Structures Influence of processing on final performance Injection molding Draping Fiber placement ...


Digimat 4.4.1 New Release

Soon available on e-Xstream FTP! (see separate email announcement)


Licensing sales.admin@e-Xstream.com

Support support@e-Xstream.com

Training bernard.alsteens@e-Xstream.com

Software jan.seyfarth@e-Xstream.com


Thanks a lot for your attention!



Documents

WS_2013_04_Advanced_Materials_Aerospace.pdf