Evaluation of a New Approach for Modeling Full Ring Stent Bundles with the Inclusion of Manufacturing Strains

Abstract

Ring stent bundles have been used in several biomedical stent-graft devices for decades, yet in the published literature, the numerical models of these structures always present significant simplifications. In this paper, a finite element (FE) ring stent bundle has been developed and evaluated with a combination of beam and surface elements. With this approach, the shape, the global stiffness and the strains of the structure can all be well predicted at a low computational cost while the approach is suitable for application to non-symmetrical, patient-specific implant simulations. The model has been validated against analytical and experimental data showing that the manufacturing strains can be predicted to a 0.1% accuracy and the structural stiffness with 0-7% precision. The model has also been compared with a more computationally expensive FE model of higher fidelity, revealing a discrepancy of 0-5% of the strain value. Finally, it has been shown that the exclusion of the manufacturing process from the simulation, a technique used in the literature, quadruples the analysis error. This is the first model that can capture the mechanical state of a full ring stent bundle, suitable for complex implant geometry simulations, with such accuracy.

Analysing The Cross-Section of The Abdominal Aortic Aneurysm Neck and Its Effects on Stent Deployment

“…A FEA stent model was assembled, compacted and deployed in each vascular section, and mechanical assessment followed. The FEA stent model used had been previously developed and validated 33 ; it is a ring stent bundle model, typical of the Scientific RepoRtS | (2020) 10:4673 | https://doi.org/10.1038/s41598-020-61578-y www.nature.com/scientificreports www.nature.com/scientificreports/ structural units found in the Anaconda TM endograft. In brief, it consists of a series of straight overlapping Nitinol wires that curve into a ring shape, to take into account the strains induced by the manufacturing process.…”

Efficiently Simulating an Endograft Deployment: A Methodology for Detailed CFD Analyses

“…A computationally efficient structural model of the ring stent bundles was achieved by representing the geometry and stiffness characteristics separately, similarly with a work developed earlier within our group. 15 More specifically, circular ring bundles were constructed using beam elements (B32, 3-node quadratic beam), enclosed by surface elements (SFM3D4R, 4-node quadrilateral surface element, reduced integration) as shown in Fig. 1 b.…”