Evaluation of a nonlinear viscoelastic-plastic constitutive model in numerical simulation of thermoplastic polymers for stent application

Abstract

To simulate the specific material properties of thermoplastic polymers a suitable constitutive model is essential. The parallel rheological framework (PRF) model was calibrated and evaluated in this study as potential constitutive model for polymer stent application. Tensile as well as recovery tests with different loading rates were performed using PLLA specimens. In order to calibrate the constitutive model, the conducted material tests were simulated accordingly. The parameters of the model were iteratively varied to obtain good accordance of the simulation with the material tests. In contrast to elastic plastic material models, viscoelastic material behavior can be represented with the nonlinear viscoelastic-plastic PRF model. The generated and possibly further refined model can be used for the simulation of polymer stents.

Keywords

• nonlinear viscoelastic-plastic constitutive model
• finite element analysis
• thermoplastic polymers
• parallel rheological framework model