F. Nagl, Acandis GmbH & Co. KG, Pforzheim, Germany; G. Siekmeyer, M. Quellmalz, Admedes Schuessler GmbH, Pforzheim, Germany; A. Schuessler, ADMEDES SCHUESSLER GmbH, Pforzheim, Germany
Nitinol (NiTi) is widely used for minimal invasive vascular implants due to its superelastic material behavior. Today computerized finite element analysis (FEA) modeling is a standard tool for the development of medical devices and an essential part of the product design and device approval process. Quality of simulation depends on a multitude of parameters such as material model and meshing. As such, the right material data input is crucial in order to calculate the true stress and strain conditions.
In this study we used different sources for material data input for our FEA simulations. We compared simulated output versus the experimental results using a stent-like structure after heat treatment. We used Nitinol literature data, tensile data from as-drawn NiTi tubes as well as tensile and compression data from micro test samples which underwent stent like processings for our FEA modelling. A FEA model of the diamond shape was constructed to quantify and visualize the force and motion response after applying different loading conditions similar to physiologic stress and strain. Force and distance response of the virtual model was compared against the differently processed diamond shape specimens. All results were put into a matrix in order to evaluate the quality of the different inputs for the FEA simulation.
Summary: The quality and accuracy of FEA simulations of Nitinol medical devices depend crucially on various parameters such as the material data and the meshing.
In this study we used different sources for material data input for our FEA simulations to compare the simulated force and distance response versus the experimental results using a diamond shape structure.
We used Nitinol literature data, tensile data from as-drawn NiTi tubes as well as tensile and compression data from micro test samples for our FEA modeling.
