Finite Element Stent Design: Parametric Modeling of Braided Wirestents Using PyFormex

Selfexpandable stent(graft)s are supporting tubular mesh devices used for the treatment of occlusive diseases and for the ‘exclusion’ of aneurysms. Wirestents are a class of flexible stents braided from a set of ultra fine wires and currently manufactured in a wide range of materials (e.g. phynox, nitinol, polymers) and compositions (single or multilayer). For design purposes as well as for studying the mechanical behavior of such a device by finite element simulations, a geometrical model using 1D elements will usually be appropriate. However, the computer model will contain a very large number of such elements, and building the geometrical model using classical CAD methodologies may become laborious. Consequently, literature dedicated to the mechanical behavior of braided wirestents is (very) scarce and the stent(graft)s are simplified as virtual single sheets [1].