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