Technical Challenge:  Bioabsorbable materials, such as polylactic acid (PLA), are finding increasing applications in medical devices. These polymers exhibit a non-linear anisotropic viscoplastic response when deformed, which requires a sophisticated material model for accurate finite element predictions.

Solution:  Veryst used the Parallel Network 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.

Result:  The more accurate material model accurately determined the stress and strain distributions, greatly assisting the design process of new device geometries. The following figure shows the contours of stress in a section of an exemplar coronary stent scaffold.