PolymerFEM Solutions for Altair Radioss™

PolymerFEM offers the PolyUMod Library of user-material models for non-linear finite element modeling of engineering polymers and biomaterials. This library provides numerically efficient material models that can be used to very accurately represent the large strain viscoplastic response of materials. The PolyUMod library contains general purpose material models that cover virtually all polymer systems, including thermoplastics, thermosets, elastomers, foams, filled plastics, and biomaterials. Specific models have also been developed for particular formulations such as fluoropolymers, PLA, and UHMWPE.

PolymerFEM has also developed the MCalibration parameter extraction software that makes it easy to calibrate any PolyUMod material model. The calibration software allows the user to analyze a set of experimental data files in order to determine the optimal model parameters. The typical workflow includes: (1) Import all relevant experimental data. This includes test data from tension, compression, shear, biaxial, and plane strain tests, as well as DMA data, dogbone-shaped tension tests, compression tests with friction, stress relaxation, creep, permanent set, Poisson’s ratio, and fatigue data. (2) Select one material model that should be calibrated to the complete set of experimental data. (3) Run the calibration using a fully automatic calibration algorithm.

The MCalibration software can calibrate both isotropic and anisotropic material models, and can also calibrate temperature-dependent material models. After the material model calibration has been completed the results can be exported to Radioss format.

Key PolyUMod Material Models

The PolyUMod library of material models contain more than 20 advanced material models. The following 3 material models are particularly useful for Radioss users:

The Bergstrom-Boyce model is an excellent model for predicting the non-linear viscoelastic response of rubbers. Radioss already supports this model for brick elements. The PolyUMod library supports both brick elements and shell elements.

The Three Network (TN) model was developed for predicting the large-strain, viscoplastic reponse of thermoplastics (in a glassy state). The TN-model is an excellent generic model for predicting the response of many different classes of both amorphous and semicrystalline thermoplastics.

The Three Network Viscoplastic (TNV) model is a general purpose viscoplastic material model capable of capturing the experimentally observed behaviors of rubbers, thermoplastic elastomers, TPU, foams, and stiff plastics. The model can capture time-dependence, pressure-dependence of plastic flow, pressure-dependent volumetric response, damage accumulation, and triaxiality-dependent failure.

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