An Advanced Thermomechanical Constitutive Model for UHMWPE

J S Bergstrom, J E Bischoff


Ultra-high molecular weight polyethylene (UHMWPE) is a material that is extensively used in biomedical devices due to its good mechanical properties, including high impact and wear resistance. In these applications the UHMWPE is often deformed beyond the limit where linear viscoelasticity is accurate, and traditional metal plasticity models are not accurate since the applied loads are not monotonic. To overcome these limitations we have developed a new advanced thermomechanical constitutive model for UHWMPE. In the new model the micostructure of the material is represented using three distinct structural domains that capture the experimentally observed non-linear, time- and temperature-dependent response at both small and large strains. The theory for the model is presented, and the model calibration and validation are exempli



fied by direct comparison with experimental data.

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