Bioabsorbable materials, such as polylactic acid (PLA), are finding increasing applications in medical devices. These polymers exhibit a nonlinear anisotropic viscoplastic response when deformed, which requires a sophisticated material model for accurate finite element predictions. PolymerFEM was asked to provide a material model to improve predictions of PLA stent stresses and strains.
We used the Parallel Network (PN) material model to analyze the stresses and strains during deployment of a coronary scaffold.
The Parallel Network Model is an advanced model that can capture the anisotropic viscoplastic response of bioabsorbable polymers. The material model predictions can also be combined with a suitable failure model to assess how close a particular device design is to a critical state during deployment.
The material model accurately determined the stress and strain distributions, greatly assisting the design process of new device geometries. The figure below shows the contours of stress in a section of an exemplar coronary stent scaffold.