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 - Frotscher, Ralf A1 - Koch, Jan-Peter A1 - Staat, Manfred T1 - Computational investigation of drug action on human-induced stem cell derived cardiomyocytes JF - Journal of biomechanical engineering Y1 - 2015 U6 - http://dx.doi.org/10.1115/1.4030173 SN - 1528-8951 (E-Journal); 0148-0731 (Print) VL - Vol. 137 IS - iss. 7 SP - 071002-1 EP - 071002-7 PB - ASME CY - New York ER - TY - JOUR A1 - Duong, Minh Tuan A1 - Nguyen, Nhu Huynh A1 - Tran, Thanh Ngoc A1 - Tolba, R. H. A1 - Staat, Manfred T1 - Influence of refrigerated storage on tensile mechanical properties of porcine liver and spleen JF - International biomechanics Y1 - 2015 U6 - http://dx.doi.org/10.1080/23335432.2015.1049295 SN - 2333-5432 VL - Vol. 2 IS - Iss. 1 SP - 79 EP - 88 PB - Taylor & Francis CY - London ER - TY - CHAP A1 - Frotscher, Ralf A1 - Staat, Manfred T1 - An electromechanical model for cardiac tissue constructs T2 - Conference proceedings of the YIC GACM 2015 : 3rd ECCOMAS Young Investigators Conference and 6th GACM Colloquium on Computational Mechanics , Aachen, 20.07.2015 - 23.07.2015 / ed.: Stefanie Elgeti ; Jaan-Willem Simon Y1 - 2015 SP - 1 EP - 4 PB - RWTH Aachen University CY - Aachen ER - TY - CHAP A1 - Bhattarai, Aroj A1 - Frotscher, Ralf A1 - Staat, Manfred T1 - Biomechanical study of the female pelvic floor dysfunction using the finite element method T2 - Conference proceedings of the YIC GACM 2015 : 3rd ECCOMAS Young Investigators Conference and 6th GACM Colloquium on Computational Mechanics , Aachen , Germany, 20.07.2015 - 23.07.2015 / ed.: Stefanie Elgeti ; Jaan-Willem Simon Y1 - 2015 SP - 1 EP - 4 PB - RWTH Aachen University CY - Aachen ER - TY - CHAP A1 - Duong, Minh Tuan A1 - Nguyen, N. H. A1 - Staat, Manfred T1 - Modeling and simulation of a growing mass by the Smoothed Finite Element Method (SFEM) T2 - Conference proceedings of the YIC GACM 2015 : 3rd ECCOMAS Young Investigators Conference and 6th GACM Colloquium on Computational Mechanics , Aachen, Germany, 20.07.2015 - 23.07.2015 / ed.: Stefanie Elgeti ; Jaan-Willem Simon Y1 - 2015 SP - 1 EP - 4 PB - RWTH Aachen University CY - Aachen ER - TY - CHAP A1 - Pham, Phu Tinh A1 - Staat, Manfred T1 - A simplification for shakedown analysis of hardening structures T2 - Conference proceedings of the YIC GACM 2015 : 3rd ECCOMAS Young Investigators Conference and 6th GACM Colloquium on Computational Mechanics , Aachen , Germany, 20.07.2015 - 23.07.2015 / ed.: Stefanie Elgeti ; Jaan-Willem Simon Y1 - 2015 SP - 1 EP - 4 PB - RWTH Aachen University CY - Aachen ER - TY - JOUR A1 - Duong, Minh Tuan A1 - Nguyen, Nhu Huynh A1 - Staat, Manfred T1 - Physical response of hyperelastic models for composite materials and soft tissues JF - Asia pacific journal on computational engineering Y1 - 2015 U6 - http://dx.doi.org/10.1186/s40540-015-0015-x SN - 2196-1166 VL - 2 IS - 3 (December 2015) SP - 1 EP - 18 ER - TY - JOUR A1 - Goßmann, Matthias A1 - Frotscher, Ralf A1 - Linder, Peter A1 - Bayer, Robin A1 - Epple, U. A1 - Staat, Manfred A1 - Temiz Artmann, Aysegül A1 - Artmann, Gerhard T1 - Mechano-pharmacological characterization of cardiomyocytes derived from human induced pluripotent stem cells JF - Cellular physiology and biochemistry N2 - Background/Aims: Common systems for the quantification of cellular contraction rely on animal-based models, complex experimental setups or indirect approaches. The herein presented CellDrum technology for testing mechanical tension of cellular monolayers and thin tissue constructs has the potential to scale-up mechanical testing towards medium-throughput analyses. Using hiPS-Cardiac Myocytes (hiPS-CMs) it represents a new perspective of drug testing and brings us closer to personalized drug medication. Methods: In the present study, monolayers of self-beating hiPS-CMs were grown on ultra-thin circular silicone membranes and deflect under the weight of the culture medium. Rhythmic contractions of the hiPS-CMs induced variations of the membrane deflection. The recorded contraction-relaxation-cycles were analyzed with respect to their amplitudes, durations, time integrals and frequencies. Besides unstimulated force and tensile stress, we investigated the effects of agonists and antagonists acting on Ca²⁺ channels (S-Bay K8644/verapamil) and Na⁺ channels (veratridine/lidocaine). Results: The measured data and simulations for pharmacologically unstimulated contraction resembled findings in native human heart tissue, while the pharmacological dose-response curves were highly accurate and consistent with reference data. Conclusion: We conclude that the combination of the CellDrum with hiPS-CMs offers a fast, facile and precise system for pharmacological, toxicological studies and offers new preclinical basic research potential. KW - Inotropic compounds KW - Pharmacology KW - Ion channels KW - CellDrum KW - Heart tissue culture KW - Induced pluripotent stem cells KW - Cardiac myocytes Y1 - 2016 U6 - http://dx.doi.org/10.1159/000443124 SN - 1421-9778 (Online) SN - 1015-8987 (Print) VL - 38 IS - 3 SP - 1182 EP - 1198 PB - Karger CY - Basel ER - TY - JOUR A1 - Frotscher, Ralf A1 - Muanghong, Danita A1 - Dursun, Gözde A1 - Goßmann, Matthias A1 - Temiz Artmann, Aysegül A1 - Staat, Manfred T1 - Sample-specific adaption of an improved electro-mechanical model of in vitro cardiac tissue JF - Journal of Biomechanics N2 - We present an electromechanically coupled computational model for the investigation of a thin cardiac tissue construct consisting of human-induced pluripotent stem cell-derived atrial, ventricular and sinoatrial cardiomyocytes. The mechanical and electrophysiological parts of the finite element model, as well as their coupling are explained in detail. The model is implemented in the open source finite element code Code_Aster and is employed for the simulation of a thin circular membrane deflected by a monolayer of autonomously beating, circular, thin cardiac tissue. Two cardio-active drugs, S-Bay K8644 and veratridine, are applied in experiments and simulations and are investigated with respect to their chronotropic effects on the tissue. These results demonstrate the potential of coupled micro- and macroscopic electromechanical models of cardiac tissue to be adapted to experimental results at the cellular level. Further model improvements are discussed taking into account experimentally measurable quantities that can easily be extracted from the obtained experimental results. The goal is to estimate the potential to adapt the presented model to sample specific cell cultures. KW - hiPS cardiomyocytes KW - Homogenization KW - Hodgkin–Huxley models KW - Frequency adaption KW - Electromechanical modeling KW - Drug simulation KW - Computational biomechanics KW - Cardiac tissue Y1 - 2016 U6 - http://dx.doi.org/10.1016/j.jbiomech.2016.01.039 SN - 0021-9290 (Print) SN - 1873-2380 (Online) VL - 49 IS - 12 SP - 2428 EP - 2435 PB - Elsevier CY - Amsterdam ER -