TY - CHAP A1 - Tran, Thanh Ngoc A1 - Staat, Manfred T1 - Uncertainty multimode failure and shakedown analysis of shells T2 - Direct methods for limit and shakedown analysis of structures / eds. Paolo Fuschi ... N2 - This paper presents a numerical procedure for reliability analysis of thin plates and shells with respect to plastic collapse or to inadaptation. The procedure involves a deterministic shakedown analysis for each probabilistic iteration, which is based on the upper bound approach and the use of the exact Ilyushin yield surface. Probabilistic shakedown analysis deals with uncertainties originated from the loads, material strength and thickness of the shell. Based on a direct definition of the limit state function, the calculation of the failure probability may be efficiently solved by using the First and Second Order Reliability Methods (FORM and SORM). The problem of reliability of structural systems (series systems) is handled by the application of a special technique which permits to find all the design points corresponding to all the failure modes. Studies show, in this case, that it improves considerably the FORM and SORM results. KW - Limit analysis KW - Shakedown analysis KW - Reliability analysis KW - Multimode failure KW - Non-linear optimization Y1 - 2015 SN - 978-3-319-12927-3 (print) ; 978-3-319-12928-0 (online) U6 - http://dx.doi.org/10.1007/978-3-319-12928-0_14 SP - 279 EP - 298 PB - Springer CY - Cham ER - TY - JOUR A1 - Staat, Manfred A1 - Heitzer, M. T1 - Traglastanalyse - ein strukturmechanisches Verfahren zur Beurteilung von gerissenen Bauteilen und Verbindungen JF - Festigkeits- und Bruchverhalten von Fügeverbindungen : 32. Tagung des DVM-Arbeitskreises Bruchvorgänge ; 22. und 23. Februar 2000 in Berlin / Richard, H. A. [Hrsg] Y1 - 2000 N1 - DVM-Bericht 232 SP - 183 EP - 192 PB - Deutscher Verband für Materialforschung und -prüfung CY - Berlin ER - TY - CHAP A1 - Frotscher, Ralf A1 - Staat, Manfred ED - Artmann, Gerhard ED - Temiz Artmann, Aysegül ED - Zhubanova, Azhar A. ED - Digel, Ilya T1 - Towards Patient-Specific Computational Modeling of hiPS-Derived Cardiomyocyte Function and Drug Action T2 - Biological, Physical and Technical Basics of Cell Engineering N2 - Human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CM) today are widely used for the investigation of normal electromechanical cardiac function, of cardiac medication and of mutations. Computational models are thus established that simulate the behavior of this kind of cells. This section first motivates the modeling of hiPS-CM and then presents and discusses several modeling approaches of microscopic and macroscopic constituents of human-induced pluripotent stem cell-derived and mature human cardiac tissue. The focus is led on the mapping of the computational results one can achieve with these models onto mature human cardiomyocyte models, the latter being the real matter of interest. Model adaptivity is the key feature that is discussed because it opens the way for modeling various biological effects like biological variability, medication, mutation and phenotypical expression. We compare the computational with experimental results with respect to normal cardiac function and with respect to inotropic and chronotropic drug effects. The section closes with a discussion on the status quo of the specificity of computational models and on what challenges have to be solved to reach patient-specificity. Y1 - 2018 SN - 978-981-10-7904-7 U6 - http://dx.doi.org/10.1007/978-981-10-7904-7_10 SP - 233 EP - 250 PB - Springer CY - Singapore ER - TY - JOUR A1 - Ciobanu, Octavian A1 - Staat, Manfred A1 - Rahimi, Alireza T1 - The use of open source software in biomechanical finite element analysis JF - Buletinul Institutului Politehnic din Iaşi / Universitatea Tehnică Gh. Asachi, Iaşi Secţia 5, Construcţii de maşini = Machine construction = Bulletin of the Polytechnic Institute of Jassy = Izvestija Jasskogo Politechničeskogo Instituta Y1 - 2008 SN - 1011-2855 VL - 54 IS - 7/8 SP - 213 EP - 220 ER - TY - BOOK A1 - Staat, Manfred A1 - Digel, Ilya A1 - Trzewik, Jürgen A1 - Sielemann, Stefanie A1 - Erni, Daniel A1 - Zylka, Waldemar T1 - Symposium Proceedings; 4th YRA MedTech Symposium 2024 : February 1 / 2024 / FH Aachen Y1 - 2024 SN - 978-3-940402-65-3 U6 - http://dx.doi.org/10.17185/duepublico/81475 PB - Universität Duisburg-Essen CY - Duisburg ER - TY - BOOK A1 - Staat, Manfred A1 - Erni, Daniel T1 - Symposium Proceedings; 3rd YRA MedTech Symposium 2019: May 24 / 2019 / FH Aachen Y1 - 2019 SN - 978-3-940402-22-6 U6 - http://dx.doi.org/10.17185/duepublico/48750 PB - Universität Duisburg-Essen CY - Duisburg ER - TY - JOUR A1 - Hackl, M. A1 - Andermahr, J. A1 - Staat, Manfred A1 - Bremer, I. A1 - Borggrefe, J. A1 - Prescher, A. A1 - Müller, L. P. A1 - Wegmann, K. T1 - Suture button reconstruction of the central band of the interosseous membrane in Essex-Lopresti lesions: a comparative biomechanical investigation JF - The Journal of Hand Surgery (European Volume) Y1 - 2017 U6 - http://dx.doi.org/10.1177/1753193416665943 SN - 2043-6289 (Online) SN - 1753-1934 (Print) VL - 42 IS - 4 SP - 370 EP - 376 PB - Sage CY - London ER - TY - JOUR A1 - Bhattarai, Aroj A1 - Jabbari, Medisa A1 - Anding, Ralf A1 - Staat, Manfred T1 - Surgical treatment of vaginal vault prolapse using different prosthetic mesh implants: a finite element analysis JF - tm - Technisches Messen N2 - Particularly multiparous elderly women may suffer from vaginal vault prolapse after hysterectomy due to weak support from lax apical ligaments. A decreased amount of estrogen and progesterone in older age is assumed to remodel the collagen thereby reducing tissue stiffness. Sacrocolpopexy is either performed as open or laparoscopic surgery using prosthetic mesh implants to substitute lax ligaments. Y-shaped mesh models (DynaMesh, Gynemesh, and Ultrapro) are implanted in a 3D female pelvic floor finite element model in the extraperitoneal space from the vaginal cuff to the first sacral (S1) bone below promontory. Numerical simulations are conducted during Valsalva maneuver with weakened tissues modeled by reduced tissue stiffness. Tissues are modeled as incompressible, isotropic hyperelastic materials whereas the meshes are modeled either as orthotropic linear elastic or as isotropic hyperlastic materials. The positions of the vaginal cuff and the bladder base are calculated from the pubococcygeal line for female pelvic floor at rest, for prolapse and after repair using the three meshes. Due to mesh mechanics and mesh pore deformation along the loaded direction, the DynaMesh with regular rectangular mesh pores is found to provide better mechanical support to the organs than the Gynemesh and the Ultrapro with irregular hexagonal mesh pores. Insbesondere ältere, mehrgebährende Frauen leiden häufiger an einem Scheidenvorfall nach einer Hysterektomie aufgrund der schwachen Unterstützung durch laxe apikale Bänder. Es wird angenommen, dass eine verringerte Menge an Östrogen und Progesteron im höheren Alter das Kollagen umformt, wodurch die Gewebesteifigkeit reduziert wird. Die Sakrokolpopexie ist eine offene oder laparoskopische Operation, die mit prothetischen Netzimplantaten durchgeführt wird, um laxe Bänder zu ersetzen. Y-förmige Netzmodelle (DynaMesh, Gynemesh und Ultrapro) werden in einem 3D-Modell des weiblichen Beckenbodens im extraperitonealen Raum vom Vaginalstumpf bis zum Promontorium implantiert. Numerische Simulationen werden während des Valsalva-Manövers mit geschwächtem Gewebe durchgeführt, das durch eine reduzierte Gewebesteifigkeit modelliert wird. Die Gewebe werden als inkompressible, isotrop hyperelastische Materialien modelliert, während die Netze entweder als orthotrope linear elastische oder als isotrope hyperlastische Materialien modelliert werden. Die Positionen des Vaginalstumpfs, der Blase und der Harnröhrenachse werden anhand der Pubococcygeallinie aus der Ruhelage, für den Prolaps und nach der Reparatur unter Verwendung der drei Netze berechnet. Aufgrund der Netzmechanik und der Netzporenverformung bietet das DynaMesh mit regelmäßigen rechteckigen Netzporen eine bessere mechanische Unterstützung und eine Neupositionierung des Scheidengewölbes, der Blase und der Urethraachse als Gynemesh und Ultrapro mit unregelmäßigen hexagonalen Netzporen. Y1 - 2018 U6 - http://dx.doi.org/10.1515/teme-2017-0115 SN - 2196-7113 VL - 85 IS - 5 SP - 331 EP - 342 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Staat, Manfred A1 - Heitzer, M. T1 - Structural Reliability Analysis of Elasto-Plastic Structures JF - Safety and reliability : proceedings of ESREL '99, the Tenth European Conference on Safety and Reliability, Munich-Garching, Germany, 13 - 17 September 1999 / Schuëller, G. I.; Kafka, P. [eds] Y1 - 1999 SN - 90-5809-109-0 SP - 513 EP - 518 PB - Balkema CY - Rotterdam ER - TY - JOUR A1 - Frotscher, Ralf A1 - Staat, Manfred T1 - Stresses produced by different textile mesh implants in a tissue equivalent JF - BioNanoMaterials N2 - Two single-incision mini-slings used for treating urinary incontinence in women are compared with respect to the stresses they produce in their surrounding tissue. In an earlier paper we experimentally observed that these implants produce considerably different stress distributions in a muscle tissue equivalent. Here we perform 2D finite element analyses to compare the shear stresses and normal stresses in the tissue equivalent for the two meshes and to investigate their failure behavior. The results clearly show that the Gynecare TVT fails for increasing loads in a zipper-like manner because it gradually debonds from the surrounding tissue. Contrary to that, the tissue at the ends of the DynaMesh-SIS direct may rupture but only at higher loads. The simulation results are in good agreement with the experimental observations thus the computational model helps to interpret the experimental results and provides a tool for qualitative evaluation of mesh implants. Y1 - 2014 U6 - http://dx.doi.org/10.1515/bnm-2014-0003 SN - 2191-4672 (E-Journal); 2193-066X (E-Journal); 0011-8656 (Print); 1616-0177 (Print); 2193-0651 (Print) VL - 15 IS - 1-2 SP - 25 EP - 30 PB - De Gruyter CY - Berlin ER -