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expert material testing | CAE material parameters | CAE Validation | software & infrastructure for materials | materials knowledge | electronic lab notebooks
New Generation Modeler for LS-DYNA Material Parameter Conversion H. Lobo and E. Strong Matereality, USA Presenters: Brian Croop Adam Beckwith
technical center for materials
materials in simulation
testing for simulation
software for materials
electronic lab notebooks
About Us
strengthening the materials core of manufacturing enterprises
Outline
• Problem definition • Background of the software space • Requirements for the new modeler • Solution • Conclusions & future work
strengthening the materials core of manufacturing enterprises
Nature of the problem
• Complex material data (multi-variate) • Parameter conversion process
• Multiple steps • Need for self-consistency • Unit conversions • Selection of options and settings • Robustness checks
• Writing of material card • No errors • Correct format
strengthening the materials core of manufacturing enterprises
Materials & CAE Material files Workflow
strengthening the materials core of manufacturing enterprises
New LS-DYNA modeler requirements
• Need for plastic strain extrapolation • Testing is usually in tensile (uniaxial) mode • Failure often occurs in other triaxiality states (biaxial, shear, combo) • Failure strains can be higher in these states
• Self-consistency checks on material parameters • Modulus change affects plasticity data • Fail strain is less than largest extrapolated plastic strain • Stress ratio modeling affects rate dependency
• Self-consistent unit systems (LS-DYNA unit systems) • Must be applied correctly across the entire parameter set
• Support for user’s material parameter conversion tools • User’s Excel macros or Python conversion scripts
strengthening the materials core of manufacturing enterprises
Basis & features
• Unified data model • Contains representation of the entire material model • Material parameters are linked to material properties • On the fly unit conversions
• GUI • Model is displayed in the context of material data
• eg. Model is displayed over rate-dependent tensile data • Drag & drop capability to move and extrapolate model lines • Changing a model parameter instantly recalculates other affected
parameters • Custom
• Export of all required properties to Excel for user post-processing
strengthening the materials core of manufacturing enterprises
Creating CAE Material files from material data
strengthening the materials core of manufacturing enterprises
Assembling the required material data
Mining the repository for materials with the required properties. Each material model can have different material data requirements.
Select a material to start material parameter conversion
strengthening the materials core of manufacturing enterprises
Assigning unit system
Selecting a unit system to ensure consistent and correct model creation
strengthening the materials core of manufacturing enterprises
Automated first pass of the material model fit
The software postulates an initial fit of the material model
strengthening the materials core of manufacturing enterprises
Preparing for extrapolation
Set the strain axis to prepare for extrapolation
strengthening the materials core of manufacturing enterprises
Extrapolation of plasticity curve
With MAT_024 – LCSR, only extrapolate the quasi-static curve For LCSS option, extrapolate each curve
Drag & drop to extrapolate
strengthening the materials core of manufacturing enterprises
Tuning stress ratio in MAT_024 LCSR option
User can visualize the effect of changing stress ratios on the model
strengthening the materials core of manufacturing enterprises
Output to LS-DYNA
File can be downloaded or saved to CAE Materials library
strengthening the materials core of manufacturing enterprises
MAT_089 modeling
Similar to MAT_024 modeling but designed for plastics. Can handle rate dependency of failure strain
strengthening the materials core of manufacturing enterprises
MAT_089 rate dependent failure strain: drag and drop
Drag and drop manipulation of failure strain
strengthening the materials core of manufacturing enterprises
MAT_089 rate dependent failure strain: table editing
Alternately, enter failure strains in table view
strengthening the materials core of manufacturing enterprises
External processing of material parameters
• Use Custom tab • Export standard
output to Excel • Apply your macros
to the standard output
• Upload your created material file
Excel file
Convert
User subroutine Material file
Import
CAE Materials
strengthening the materials core of manufacturing enterprises
Conclusions
• Intuitive software to create material parameters from raw data • Drag & drop model manipulation • Unit systems are managed • Ability to quickly prepare material cards • Validation step is valuable to confirm model parameters, other
settings.
strengthening the materials core of manufacturing enterprises
Future Work
• Extrapolation based upon plasticity equations • Expansion to other complex models
• Visco-elasticity • Rubber hyper-elasticity • Foam models • SAMP
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