TY - JOUR A1 - Geith, Markus A. A1 - Swidergal, Krzysztof A1 - Hochholdinger, Bernd A1 - Schratzenstaller, Thomas A1 - Wagner, Marcus A1 - Holzapfel, Gerhard A. T1 - On the importance of modeling balloon folding, pleating, and stent crimping: An FE study comparing experimental inflation tests JF - International Journal for Numerical Methods in Biomedical Engineering N2 - Finite element (FE)–based studies of preoperative processes such as folding,pleating, and stent crimping with a comparison with experimental inflation tests are not yet available. Therefore, a novel workflow is presented in which residual stresses of balloon folding and pleating, as well as stent crimping, and the geometries of all contact partners were ultimately implemented in an FE code to simulate stent expansion by using an implicit solver. The numerical results demonstrate that the incorporation of residual stresses and strains experienced during the production step significantly increased the accuracy of the subsequent simulations, especially of the stent expansion model. During the preoperative processes, stresses inside the membrane and the stent material also reached a rather high level. Hence, there can be no presumption that balloon catheters or stents are undamaged before the actual surgery. The implementation of the realistic geometry, in particular the balloon tapers, and the blades of the process devices improved the simulation of the expansion mech-anisms, such as dogboning, concave bending, or overexpansion of stent cells. This study shows that implicit solvers are able to precisely simulate the mentioned preoperative processes and the stent expansion procedure without a preceding manipulation of the simulation time or physical mass. KW - Catheter KW - Coronary KW - Crimping KW - Finite element KW - Stent KW - Stent KW - Implantation KW - Simulation KW - Finite-Elemente-Methode Y1 - 2019 U6 - https://doi.org/10.1002/cnm.3249 N1 - This study was funded by the Bavarian Research Foundation within the project “PIZ‐225‐18” VL - 35 IS - 11 PB - Wiley ER - TY - JOUR A1 - Wagner, Bernd A1 - Neidhart, Thomas T1 - Prognose der Druckfestigkeitsentwicklung von ZFSV : Vorschlag zweier Methoden JF - Euroheat & Power Y1 - 2016 SN - 0949-166X VL - 45 IS - 1/2 SP - 35 EP - 39 PB - VDE Verlag ER - TY - CHAP A1 - Wagner, Bernd A1 - Hay, Stefan A1 - Neidhart, Thomas A1 - Spirkl, Florian A1 - Ried, Michael A1 - Zrenner, Louis A1 - Weidlich, Ingo A1 - Gabriel, Eugen A1 - Banning, Timo ED - Vanhoudt, Dirk T1 - TFSB as Bedding Material in District Heating Pipe Constructin - Scientifically Proven Long-Term Experience T2 - Proceedings of the 19th International Symposium on District Heating and Cooling; 2025, Genk (Belgium) N2 - Following the explanation of the increasing importance of alternative backfill materials like TFSB, TFSB and their status in terms of science and technology are depicted. Selected results of the research project FW-ZFSV 4.0 are presented: computer-aided static calculation, in situ long term loading of district heating pipes in TFSB and sand, quality assurance and resource conservation. The conclusions provide an overall assessment of the use of TFSB in district heating pipe construction. Y1 - 2026 SN - 9783032098443 U6 - https://doi.org/10.1007/978-3-032-09844-3_10 SP - 99 EP - 108 PB - Springer CY - Cham ER -