Nitinol Stent Placement in a Stenosed Artery: A Highly Nonlinear Application Scenario for Two Novel Finite-Element Models

Abstract Shape memory alloys are complex materials with unique properties. Their appropriate modeling necessitates thermomechanically coupled approaches. A numerically robust and efficient material model that is based on energy principles has been presented in previous studies. The present work demonstrates its applicability to complex loading scenarios. To this end, the placement of a stent in a narrowed artery which damages is simulated. For the stent, a Nitinol material model is used and contact conditions between the stent and the artery wall are considered which introduce highly nonlinear kinematic constraints on the displacement field. Furthermore, the artery is modeled by Neo-Hookean hyperelasticity, including damage evolution. Gradient enhancement is included for regularization purposes. Hence, the presented numerical studies not only prove the applicability of both models to highly nonlinear simulation scenarios, they further allow for the investigation of stent-induced arterial injury. The latter, in turn, is known to initiate inflammatory responses in arteries which can lead to pathologic tissue responses. Concluding, both models can contribute to the investigation of new stent designs and stent–artery interactions to reduce arterial injury after cardiovascular interventions.