Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Quelle der Hochschulschrift Konferenzname Bemerkung Quelle:Titel Quelle:Jahrgang Quelle:Heftnummer Quelle:Erste Seite Quelle:Letzte Seite URN DOI Zugriffsart Link Abteilungen OPUS4-10589 Konferenzveröffentlichung Tran, Ngoc Trinh, Trinh.tran@fh-aachen.de; Trinh, Tu Luc, ; Dao, Ngoc Tien, ; Giap, Van Tan, ; Truong, Manh Khuyen, ; Dinh, Thuy Ha, ; Staat, Manfred, m.staat@fh-aachen.de Limit and shakedown analysis of structures under random strength Direct methods comprising limit and shakedown analysis is a branch of computational mechanics. It plays a significant role in mechanical and civil engineering design. The concept of direct method aims to determinate the ultimate load bearing capacity of structures beyond the elastic range. For practical problems, the direct methods lead to nonlinear convex optimization problems with a large number of variables and onstraints. If strength and loading are random quantities, the problem of shakedown analysis is considered as stochastic programming. This paper presents a method so called chance constrained programming, an effective method of stochastic programming, to solve shakedown analysis problem under random condition of strength. In this our investigation, the loading is deterministic, the strength is distributed as normal or lognormal variables. Hanoi Nha xuat ban Khoa hoc tu nhien va Cong nghe (Verlag Naturwissenschaft und Technik) 2022 8 Proceedings of (NACOME2022) The 11th National Conference on Mechanics, Vol. 1. Solid Mechanics, Rock Mechanics, Artificial Intelligence, Teaching and Training, Hanoi, December 2-3, 2022 978-604-357-084-7 510 518 weltweit https://www.researchgate.net/publication/366053333_Shakedown_analysis_of_structures_under_random_strength_by_chance_constrained_programming Fachbereich Medizintechnik und Technomathematik OPUS4-10346 Konferenzveröffentlichung Staat, Manfred, m.staat@fh-aachen.de; Tran, Ngoc Trinh, Trinh.tran@fh-aachen.de Strain based brittle failure criteria for rocks When confining pressure is low or absent, extensional fractures are typical, with fractures occurring on unloaded planes in rock. These "paradox" fractures can be explained by a phenomenological extension strain failure criterion. In the past, a simple empirical criterion for fracture initiation in brittle rock has been developed. But this criterion makes unrealistic strength predictions in biaxial compression and tension. A new extension strain criterion overcomes this limitation by adding a weighted principal shear component. The weight is chosen, such that the enriched extension strain criterion represents the same failure surface as the Mohr-Coulomb (MC) criterion. Thus, the MC criterion has been derived as an extension strain criterion predicting failure modes, which are unexpected in the understanding of the failure of cohesive-frictional materials. In progressive damage of rock, the most likely fracture direction is orthogonal to the maximum extension strain. The enriched extension strain criterion is proposed as a threshold surface for crack initiation CI and crack damage CD and as a failure surface at peak P. Examples show that the enriched extension strain criterion predicts much lower volumes of damaged rock mass compared to the simple extension strain criterion. Hanoi Nha xuat ban Khoa hoc tu nhien va Cong nghe (Verlag Naturwissenschaft und Technik) 2022 9 Proceedings of (NACOME2022) The 11th National Conference on Mechanics, Vol. 1. Solid Mechanics, Rock Mechanics, Artificial Intelligence, Teaching and Training, Hanoi, December 2-3, 2022 978-604-357-084-7 500 509 weltweit https://www.researchgate.net/publication/366053178_Strain_based_failure_criteria_for_rocks Fachbereich Medizintechnik und Technomathematik OPUS4-9610 Konferenzveröffentlichung Tran, Ngoc Trinh, Trinh.tran@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de FEM shakedown analysis of Kirchhoff-Love plates under uncertainty of strength A new formulation to calculate the shakedown limit load of Kirchhoff plates under stochastic conditions of strength is developed. Direct structural reliability design by chance con-strained programming is based on the prescribed failure probabilities, which is an effective approach of stochastic programming if it can be formulated as an equivalent deterministic optimization problem. We restrict uncertainty to strength, the loading is still deterministic. A new formulation is derived in case of random strength with lognormal distribution. Upper bound and lower bound shakedown load factors are calculated simultaneously by a dual algorithm. 2021 Paper ID: E19047 Proceedings of UNCECOMP 2021 978-618-85072-6-5 Proceedings of UNCECOMP 2021, 4th International Conference on Uncertainty Quantification in Computational Sciences and Engineering, streamed from Athens, Greece, 28-30 June 2021. 323 338 10.7712/120221.8041.19047 weltweit https://doi.org/10.7712/120221.8041.19047 Fachbereich Medizintechnik und Technomathematik OPUS4-8926 Konferenzveröffentlichung Raman, Aravind Hariharan, ; Jung, Alexander, ; Horváth, András, ; Becker, Nadine, ; Staat, Manfred, m.staat@fh-aachen.de Staat, Manfred; Erni, Daniel Modification of a computer model of human stem cell-derived cardiomyocyte electrophysiology based on Patch-Clamp measurements Human induced pluripotent stem cells (hiPSCs) have shown to be promising in disease studies and drug screenings [1]. Cardiomyocytes derived from hiPSCs have been extensively investigated using patch-clamping and optical methods to compare their electromechanical behaviour relative to fully matured adult cells. Mathematical models can be used for translating findings on hiPSCCMs to adult cells [2] or to better understand the mechanisms of various ion channels when a drug is applied [3,4]. Paci et al. (2013) [3] developed the first model of hiPSC-CMs, which they later refined based on new data [3]. The model is based on iCells® (Fujifilm Cellular Dynamics, Inc. (FCDI), Madison WI, USA) but major differences among several cell lines and even within a single cell line have been found and motivate an approach for creating sample-specific models. We have developed an optimisation algorithm that parameterises the conductances (in S/F=Siemens/Farad) of the latest Paci et al. model (2018) [5] using current-voltage data obtained in individual patch-clamp experiments derived from an automated patch clamp system (Patchliner, Nanion Technologies GmbH, Munich). Duisburg Universität Duisburg-Essen 2019 1 3rd YRA MedTech Symposium 2019 : May 24 / 2019 / FH Aachen 978-3-940402-22-6 10 11 10.17185/duepublico/48750 weltweit https://doi.org/10.17185/duepublico/48750 Fachbereich Medizintechnik und Technomathematik OPUS4-8924 Konferenzveröffentlichung Hunker, Jan, ; Jung, Alexander, ; Goßmann, Matthias, ; Linder, Peter, linder@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Staat, Manfred; Erni, Daniel Development of a tool to analyze the conduction speed in microelectrode array measurements of cardiac tissue The discovery of human induced pluripotent stem cells reprogrammed from somatic cells [1] and their ability to differentiate into cardiomyocytes (hiPSC-CMs) has provided a robust platform for drug screening [2]. Drug screenings are essential in the development of new components, particularly for evaluating the potential of drugs to induce life-threatening pro-arrhythmias. Between 1988 and 2009, 14 drugs have been removed from the market for this reason [3]. The microelectrode array (MEA) technique is a robust tool for drug screening as it detects the field potentials (FPs) for the entire cell culture. Furthermore, the propagation of the field potential can be examined on an electrode basis. To analyze MEA measurements in detail, we have developed an open-source tool. Duisburg Universität Duisburg-Essen 2019 1 3rd YRA MedTech Symposium 2019 : May 24 / 2019 / FH Aachen 978-3-940402-22-6 7 8 10.17185/duepublico/48750 https://doi.org/10.17185/duepublico/48750 Fachbereich Medizintechnik und Technomathematik OPUS4-8395 Konferenzveröffentlichung Kahmann, Stephanie Lucina, ; Uschok, Stephan, ; Wegmann, Kilian, ; Müller, Lars-P., ; Staat, Manfred, m.staat@fh-aachen.de Biomechanical multibody model with refined kinematics of the elbow The overall objective of this study is to develop a new external fixator, which closely maps the native kinematics of the elbow to decrease the joint force resulting in reduced rehabilitation time and pain. An experimental setup was designed to determine the native kinematics of the elbow during flexion of cadaveric arms. As a preliminary study, data from literature was used to modify a published biomechanical model for the calculation of the joint and muscle forces. They were compared to the original model and the effect of the kinematic refinement was evaluated. Furthermore, the obtained muscle forces were determined in order to apply them in the experimental setup. The joint forces in the modified model differed slightly from the forces in the original model. The muscle force curves changed particularly for small flexion angles but their magnitude for larger angles was consistent. 2018 11 Seiten 6th European Conference on Computational Mechanics (ECCM 6), 7th European Conference on Computational Fluid Dynamics (ECFD 7), 11-15 June 2018, Glasgow, UK weltweit http://www.eccm-ecfd2018.org/admin/files/filePaper/p2085.pdf Fachbereich Medizintechnik und Technomathematik OPUS4-8394 Konferenzveröffentlichung Jung, Alexander, ; Frotscher, Ralf, Frotscher@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Electromechanical model of hiPSC-derived ventricular cardiomyocytes cocultured with fibroblasts The CellDrum provides an experimental setup to study the mechanical effects of fibroblasts co-cultured with hiPSC-derived ventricular cardiomyocytes. Multi-scale computational models based on the Finite Element Method are developed. Coupled electrical cardiomyocyte-fibroblast models (cell level) are embedded into reaction-diffusion equations (tissue level) which compute the propagation of the action potential in the cardiac tissue. Electromechanical coupling is realised by an excitation-contraction model (cell level) and the active stress arising during contraction is added to the passive stress in the force balance, which determines the tissue displacement (tissue level). Tissue parameters in the model can be identified experimentally to the specific sample. 2018 11 Seiten 6th European Conference on Computational Mechanics (ECCM 6), 7th European Conference on Computational Fluid Dynamics (ECFD 7), 11-15 June 2018, Glasgow, UK weltweit Fachbereich Medizintechnik und Technomathematik OPUS4-8393 Konferenzveröffentlichung Tran, Ngoc Trinh, Trinh.tran@fh-aachen.de; Matthies, Hermann G., ; Stavroulakis, Georgios Eleftherios, ; Staat, Manfred, m.staat@fh-aachen.de Direct plastic structural design by chance constrained programming We propose a stochastic programming method to analyse limit and shakedown of structures under random strength with lognormal distribution. In this investigation a dual chance constrained programming algorithm is developed to calculate simultaneously both the upper and lower bounds of the plastic collapse limit or the shakedown limit. The edge-based smoothed finite element method (ES-FEM) using three-node linear triangular elements is used. 2018 12 Seiten 6th European Conference on Computational Mechanics (ECCM 6), 7th European Conference on Computational Fluid Dynamics (ECFD 7), 11-15 June 2018, Glasgow, UK weltweit https://congress.cimne.com/eccm_ecfd2018/admin/files/fileabstract/a1777.pdf Fachbereich Medizintechnik und Technomathematik OPUS4-8354 Konferenzveröffentlichung Bhattarai, Aroj, bhattarai@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Fernandes, P.R.; Tavares, J. M. Pectopexy to repair vaginal vault prolapse: a finite element approach The vaginal prolapse after hysterectomy (removal of the uterus) is often associated with the prolapse of the vaginal vault, rectum, bladder, urethra or small bowel. Minimally invasive surgery such as laparoscopic sacrocolpopexy and pectopexy are widely performed for the treatment of the vaginal prolapse with weakly supported vaginal vault after hysterectomy using prosthetic mesh implants to support (or strengthen) lax apical ligaments. Implants of different shape, size and polymers are selected depending on the patient's anatomy and the surgeon's preference. In this computational study on pectopexy, DynaMesh®-PRP soft, GYNECARE GYNEMESH® PS Nonabsorbable PROLENE® soft and Ultrapro® are tested in a 3D finite element model of the female pelvic floor. The mesh model is implanted into the extraperitoneal space and sutured to the vaginal stump with a bilateral fixation to the iliopectineal ligament at both sides. Numerical simulations are conducted at rest, after surgery and during Valsalva maneuver with weakened tissues modeled by reduced tissue stiffness. Tissues and prosthetic meshes are modeled as incompressible, isotropic hyperelastic materials. The positions of the organs are calculated with respect to the pubococcygeal line (PCL) for female pelvic floor at rest, after repair and during Valsalva maneuver using the three meshes. 2018 Proceedings CMBBE 2018 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering and 3rd Conference on Imaging and Visualization. CMBBE 2018. 26-29 March 2018, Lisbon, Portugal weltweit http://cmbbe2018.tecnico.ulisboa.pt/pen_cmbbe2018/pdf/WEB_PAPERS/CMBBE2018_paper_148.pdf Fachbereich Medizintechnik und Technomathematik OPUS4-8076 Konferenzveröffentlichung Jabbari, Medisa, ; Bhattarai, Aroj, ; Anding, Ralf, ; Staat, Manfred, m.staat@fh-aachen.de Erni, Daniel; Fischerauer, Alice; Himmel, Jörg; Seeger, Thomas; Thelen, Klaus Biomechanical simulation of different prosthetic meshes for repairing uterine/vaginal vault prolapse Duisburg Universität Duisburg-Essen 2017 1 2nd YRA MedTech Symposium 2017 : June 8th - 9th / 2017 / Hochschule Ruhr-West 978-3-9814801-9-1 A young researchers track of the 7th IEEE Workshop & SENSORICA 2017 118 119 10.17185/duepublico/43984 weltweit https://doi.org/10.17185/duepublico/43984 Fachbereich Medizintechnik und Technomathematik OPUS4-8075 Konferenzveröffentlichung Birgel, Stefan, ; Leschinger, Tim, ; Wegmann, Kilian, ; Staat, Manfred, m.staat@fh-aachen.de Erni, Daniel; Fischerauer, Alice; Himmel, Jörg; Seeger, Thomas; Thelen, Klaus Calculation of muscle forces and joint reaction loads in shoulder area via an OpenSim based computer calculation Duisburg Universität Duisburg-Essen 2017 1 2nd YRA MedTech Symposium 2017 : June 8th - 9th / 2017 / Hochschule Ruhr-West 978-3-9814801-9-1 A young researchers track of the 7th IEEE Workshop & SENSORICA 2017 116 117 10.17185/duepublico/43984 weltweit https://doi.org/10.17185/duepublico/43984 Fachbereich Medizintechnik und Technomathematik OPUS4-8074 Konferenzveröffentlichung Abel, Alexander, ; Pérez-Viana, Daniel, ; Ciritsis, Bernard, ; Staat, Manfred, m.staat@fh-aachen.de Erni, Daniel; Fischerauer, Alice; Himmel, Jörg; Seeger, Thomas; Thelen, Klaus Prevention of femur neck fractures through femoroplasty Duisburg Universität Duisburg-Essen 2017 1 2nd YRA MedTech Symposium 2017 : June 8th - 9th / 2017 / Hochschule Ruhr-West 978-3-9814801-9-1 A young researchers track of the 7th IEEE Workshop & SENSORICA 2017 114 115 10.17185/duepublico/43984 weltweit https://doi.org/10.17185/duepublico/43984 Fachbereich Medizintechnik und Technomathematik OPUS4-7860 Konferenzveröffentlichung Tran, Ngoc Trinh, ; Tran, Thanh Ngoc, tran@fh-aachen.de; Matthies, Hermann G., ; Stavroulakis, Georgios Eleftherios, ; Staat, Manfred, m.staat@fh-aachen.de FEM Shakedown of uncertain structures by chance constrained programming 2016 1 PAMM Proceedings in Applied Mathematics and Mechanics 16 Special Issue: Joint 87th Annual Meeting of the International Association of Applied Mathematics and Mechanics (GAMM) and Deutsche Mathematiker-Vereinigung 1 715 716 10.1002/pamm.201610346 campus http://doi.org/10.1002/pamm.201610346 Fachbereich Medizintechnik und Technomathematik OPUS4-7859 Konferenzveröffentlichung Staat, Manfred, m.staat@fh-aachen.de; Duong, Minh Tuan, duong@fh-aachen.de Smoothed Finite Element Methods for Nonlinear Solid Mechanics Problems: 2D and 3D Case Studies The Smoothed Finite Element Method (SFEM) is presented as an edge-based and a facebased techniques for 2D and 3D boundary value problems, respectively. SFEMs avoid shortcomings of the standard Finite Element Method (FEM) with lower order elements such as overly stiff behavior, poor stress solution, and locking effects. Based on the idea of averaging spatially the standard strain field of the FEM over so-called smoothing domains SFEM calculates the stiffness matrix for the same number of degrees of freedom (DOFs) as those of the FEM. However, the SFEMs significantly improve accuracy and convergence even for distorted meshes and/or nearly incompressible materials. Numerical results of the SFEMs for a cardiac tissue membrane (thin plate inflation) and an artery (tension of 3D tube) show clearly their advantageous properties in improving accuracy particularly for the distorted meshes and avoiding shear locking effects. 2016 5 Proceedings of the National Science and Technology Conference on Mechanical - Transportation Engineering (NSCMET 2016), 13th October 2016, Hanoi, Vietnam, Vol.2 440 445 weltweit http://doi.org/10.21269/7859 Fachbereich Medizintechnik und Technomathematik OPUS4-7841 Konferenzveröffentlichung Bhattarai, Aroj, bhattarai@fh-aachen.de; Frotscher, Ralf, Frotscher@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Natal Jorge, Renato Significance of fibre geometry on passive-active response of pelvic muscles to evaluate pelvic dysfunction Boca Raton CRC Press 2016 3 BioMedWomen: Proceedings of the international conference on clinical and bioengineering for women's health 978-1-138-02910-1 185 188 Fachbereich Medizintechnik und Technomathematik OPUS4-7818 Konferenzveröffentlichung Tran, Ngoc Trinh, ; Tran, Thanh Ngoc, tran@fh-aachen.de; Matthies, H. G., ; Stavroulakis, G. E., ; Staat, Manfred, m.staat@fh-aachen.de Papadrakakis, M. Shakedown analysis of plate bending analysis under stochastic uncertainty by chance constrained programming 2016 13 S. ECCOMAS Congress 2016, VII European Congress on Computational Methods in Applied Sciences and Engineering. Crete Island, Greece, 5–10 June 2016 https://www.eccomas2016.org/proceedings/pdf/11106.pdf Fachbereich Medizintechnik und Technomathematik OPUS4-7817 Konferenzveröffentlichung Duong, Minh Tuan, duong@fh-aachen.de; Jung, Alexander, ; Frotscher, Ralf, frotscher@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Papadrakakis, M. A 3D electromechanical FEM-based model for cardiac tissue 2016 13 S. ECCOMAS Congress 2016, VII European Congress on Computational Methods in Applied Sciences and Engineering. Crete Island, Greece, 5–10 June 2016 revised after the conference P11367 Fachbereich Medizintechnik und Technomathematik OPUS4-7735 Konferenzveröffentlichung Kahmann, Stephanie, ; Hackl, Michael, ; Wegmann, Kilian, ; Müller, Lars-Peter, ; Staat, Manfred, m.staat@fh-aachen.de Erni, Daniel Impact of a proximal radial shortening osteotomy on the distribution of forces and the stability of the elbow The human arm consists of the humerus (upper arm), the medial ulna and the lateral radius (forearm). The joint between the humerus and the ulna is called humeroulnar joint and the joint between the humerus and the radius is called humeroradial joint. Lateral and medial collateral ligaments stabilize the elbow. Statistically, 2.5 out of 10,000 people suffer from radial head fractures [1]. In these fractures the cartilage is often affected. Caused by the injured cartilage, degenerative diseases like posttraumatic arthrosis may occur. The resulting pain and reduced range of motion have an impact on the patient's quality of life. Until now, there has not been a treatment which allows typical loads in daily life activities and offers good long-term results. A new surgical approach was developed with the motivation to reduce the progress of the posttraumatic arthrosis. Here, the radius is shortened by 3 mm in the proximal part [2]. By this means, the load of the radius is intended to be reduced due to a load shift to the ulna. Since the radius is the most important stabilizer of the elbow it has to be confirmed that the stability is not affected. In the first test (Fig. 1 left), pressure distributions within the humeroulnar and humeroradial joints a native and a shortened radius were measured using resistive pressure sensors (I5076 and I5027, Tekscan, USA). The humerus was loaded axially in a tension testing machine (Z010, Zwick Roell, Germany) in 50 N steps up to 400 N. From the humerus the load is transmitted through both the radius and the ulna into the hand which is fixed on the ground. In the second test (Fig. 1 right), the joint stability was investigated using a digital image correlation system to measure the displacement of the ulna. Here, the humerus is fixed with a desired flexion angle and the unconstrained forearm lies on the ground. A rope connects the load actuator with a hook fixed in the ulna. A guide roller is used so that the rope pulls the ulna horizontally when a tensile load is applied. This creates a moment about the elbow joint with a maximum value of 7.5 Nm. Measurements were performed with varying flexion angles (0°, 30°, 60°, 90°, 120°). For both tests and each measurement, seven specimens were used. Student's t-test was employed to determine whether the mean values of the measurements in native specimen and operated specimens differ significantly. Duisburg Universität Duisburg-Essen 2016 1 1st YRA MedTech Symposium 2016 : April 8th / 2016 / University of Duisburg-Essen 7 8 10.17185/duepublico/40821 weltweit https://doi.org/10.17185/duepublico/40821 Fachbereich Medizintechnik und Technomathematik OPUS4-7734 Konferenzveröffentlichung Jung, Alexander, ; Staat, Manfred, m.staat@fh-aachen.de Erni, Daniel Computing olympic gold: Ski jumping as an example Duisburg Universität Duisburg-Essen 2016 1 1st YRA MedTech Symposium 2016 : April 8th / 2016 / University of Duisburg-Essen 978-3-940402-06-6 54 55 10.17185/duepublico/40821 weltweit https://doi.org/10.17185/duepublico/40821 Fachbereich Medizintechnik und Technomathematik OPUS4-7733 Konferenzveröffentlichung Bhattarai, Aroj, bhattarai@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Erni, Daniel Female pelvic floor dysfunction: progress weakening of the support system The structure of the female pelvic floor (PF) is an inter-related system of bony pelvis,muscles, pelvic organs, fascias, ligaments, and nerves with multiple functions. Mechanically, thepelvic organ support system are of two types: (I) supporting system of the levator ani (LA) muscle,and (II) the suspension system of the endopelvic fascia condensation [1], [2]. Significantdenervation injury to the pelvic musculature, depolimerization of the collagen fibrils of the softvaginal hammock, cervical ring and ligaments during pregnancy and vaginal delivery weakens thenormal functions of the pelvic floor. Pelvic organ prolapse, incontinence, sexual dysfunction aresome of the dysfunctions which increases progressively with age and menopause due toweakened support system according to the Integral theory [3]. An improved 3D finite elementmodel of the female pelvic floor as shown in Fig. 1 is constructed that: (I) considers the realisticsupport of the organs to the pelvic side walls, (II) employs the improvement of our previous FEmodel [4], [5] along with the patient based geometries, (III) incorporates the realistic anatomy andboundary conditions of the endopelvic (pubocervical and rectovaginal) fascia, and (IV) considersvarying stiffness of the endopelvic fascia in the craniocaudal direction [3]. Several computationsare carried out on the presented computational model with healthy and damaged supportingtissues, and comparisons are made to understand the physiopathology of the female PF disorders. Duisburg Universität Duisburg-Essen 2016 1 1st YRA MedTech Symposium 2016 : April 8th / 2016 / University of Duisburg-Essen 11 12 10.17185/duepublico/40821 weltweit https://doi.org/10.17185/duepublico/40821 Fachbereich Medizintechnik und Technomathematik OPUS4-7624 Konferenzveröffentlichung Jung, Alexander, ; Staat, Manfred, m.staat@fh-aachen.de; Müller, Wolfram, Effect of wind on flight style optimisation in ski jumping Edinburgh The University of Edinburgh ; Loughborough University 2016 1 15th International Symposium on Computer Simulation in Biomechanics ; July 9th-11th 2015, Edinburgh, UK 53 54 weltweit http://iscsb2015.lboro.ac.uk/ISCSB_book_of_abstracts.pdf Fachbereich Medizintechnik und Technomathematik OPUS4-7442 Konferenzveröffentlichung Frotscher, Ralf, frotscher@fh-aachen.de; Duong, Minh Tuan, duong@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Simulating beating cardiomyocytes with electromechanical coupling 2015 1 II. International Conference on Biomedical Technology : 28-30 October 2015 Hannover, Germany / T. Lenarz, P. Wriggers (Eds.) 1 2 Fachbereich Medizintechnik und Technomathematik OPUS4-7303 Konferenzveröffentlichung Pham, Phu Tinh, ; Staat, Manfred, m.staat@fh-aachen.de A simplification for shakedown analysis of hardening structures Aachen RWTH Aachen University 2015 3 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 1 4 weltweit http://nbn-resolving.de/urn:nbn:de:hbz:82-rwth-2015-039806 Fachbereich Medizintechnik und Technomathematik OPUS4-7302 Konferenzveröffentlichung Duong, Minh Tuan, duong@fh-aachen.de; Nguyen, N. H., ; Staat, Manfred, m.staat@fh-aachen.de Modeling and simulation of a growing mass by the Smoothed Finite Element Method (SFEM) Aachen RWTH Aachen University 2015 3 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 1 4 weltweit http://nbn-resolving.de/urn:nbn:de:hbz:82-rwth-2015-039806 Fachbereich Medizintechnik und Technomathematik OPUS4-7301 Konferenzveröffentlichung Bhattarai, Aroj, bhattarai@fh-aachen.de; Frotscher, Ralf, frotscher@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Biomechanical study of the female pelvic floor dysfunction using the finite element method Aachen RWTH Aachen University 2015 3 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 1 4 weltweit http://nbn-resolving.de/urn:nbn:de:hbz:82-rwth-2015-039806 Fachbereich Medizintechnik und Technomathematik OPUS4-7300 Konferenzveröffentlichung Frotscher, Ralf, frotscher@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de An electromechanical model for cardiac tissue constructs Aachen RWTH Aachen University 2015 3 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 1 4 weltweit http://nbn-resolving.de/urn:nbn:de:hbz:82-rwth-2015-039806 Fachbereich Medizintechnik und Technomathematik OPUS4-7263 Konferenzveröffentlichung Frotscher, Ralf, frotscher@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Nithiarasu, Perumal Homogenization of a cardiac tissue construct [s.l.] CMBE 2015 3 CMBE15 : 4th International Conference on Computational & Mathematical Biomedical Engineering ; 29th June - 1st July 2015 ; École Normale Supérieure de Cachan ; Cachan (Paris), France Konferenzband unter: http://www.compbiomed.net/getfile.php?type=12/site_documents&id=Proceedings_2227-9385_compressed.pdf 645 648 weltweit http://doi.org/10.21269/7263 Fachbereich Medizintechnik und Technomathematik OPUS4-6510 Konferenzveröffentlichung Tran, Ngoc Trinh, ; Staat, Manfred, m.staat@fh-aachen.de; Stavroulakis, G. E., Onate, E. A multicriteria method for truss optimization 2014 11 11th World Congress on Computational Mechanics (WCCM XI) ; 5th European Conference on Computational Mechanics (ECCM V) ; 6th European Conference on Computational Fluid Dynamics (ECFD VI) ; July 20-25, 2014, Barcelona 1 12 Fachbereich Medizintechnik und Technomathematik OPUS4-6509 Konferenzveröffentlichung Duong, Minh Tuan, duong@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Onate, E. A face-based smoothed finite element method for hyperelastic models and tissue growth 2014 11 11th World Congress on Computational Mechanics (WCCM XI) ; 5th European Conference on Computational Mechanics (ECCM V) ; 6th European Conference on Computational Fluid Dynamics (ECFD VI) ; July 20-25, 2014, Barcelona 1 12 Fachbereich Medizintechnik und Technomathematik OPUS4-6508 Konferenzveröffentlichung Tran, Thanh Ngoc, tran@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Onate, E. Uncertain multimode failure and limit analysis of shells 2014 11 11th World Congress on Computational Mechanics (WCCM XI) ; 5th European Conference on Computational Mechanics (ECCM V) ; 6th European Conference on Computational Fluid Dynamics (ECFD VI) ; July 20-25, 2014, Barcelona 1 12 Fachbereich Medizintechnik und Technomathematik OPUS4-6507 Konferenzveröffentlichung Bhattarai, Aroj, bhattarai@fh-aachen.de; Frotscher, Ralf, frotscher@fh-aachen.de; Sora, M.-C., ; Staat, Manfred, m.staat@fh-aachen.de Onate, E. A 3D finite element model of the female pelvic floor for the reconstruction of urinary incontinence 2014 11 11th World Congress on Computational Mechanics (WCCM XI) ; 5th European Conference on Computational Mechanics (ECCM V) ; 6th European Conference on Computational Fluid Dynamics (ECFD VI) ; July 20-25, 2014, Barcelona 1 12 Fachbereich Medizintechnik und Technomathematik OPUS4-6506 Konferenzveröffentlichung Jung, Alexander, ; Staat, Manfred, m.staat@fh-aachen.de; Müller, Wolfram, Onate, E. Optimization of the flight style in ski jumping 2014 11 11th World Congress on Computational Mechanics (WCCM XI) ; 5th European Conference on Computational Mechanics (ECCM V) ; 6th European Conference on Computational Fluid Dynamics (ECFD VI) ; July 20 - 25, 2014, Barcelona Das Paper wurde nach der Konferenz überarbeitet. 799 810 Fachbereich Medizintechnik und Technomathematik OPUS4-6505 Konferenzveröffentlichung Frotscher, Ralf, frotscher@fh-aachen.de; Koch, Jan-Peter, ; Raatschen, Hans-Jürgen, raatschen@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Onate, E. Evaluation of a computational model for drug action on cardiac tissue 2014 11 11th World Congress on Computational Mechanics (WCCM XI) ; 5th European Conference on Computational Mechanics (ECCM V) ; 6th European Conference on Computational Fluid Dynamics (ECFD VI) ; July 20 - 25, 2014, Barcelona 1 12 Fachbereich Medizintechnik und Technomathematik OPUS4-5904 Konferenzveröffentlichung Frotscher, Ralf, frotscher@fh-aachen.de; Goßmann, Matthias, gossmann@fh-aachen.de; Temiz Artmann, Aysegül, a.artmann@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Simulation of cardiac cell-seeded membranes using the edge-based smoothed FEM Minsk Verl. d. Weißruss. Staatl. Univ. 2013 2 1st International Conference "Shell and Membrane Theories in Mechanics and Biology: From Macro- to Nanoscale Structures", Minsk, Belarus, Sept. 16-20, 2013 978-985-553-135-8 165 167 weltweit http://elib.bsu.by/handle/123456789/56608 Fachbereich Medizintechnik und Technomathematik OPUS4-5111 Konferenzveröffentlichung Duong, Minh Tuan, duong@fh-aachen.de; Nguyen, Nhu Hunyh, ; Staat, Manfred, m.staat@fh-aachen.de Finite Element Implementation of a 3D Fung-type Model Graz Verlag d. Technischen Universität Graz 2012 ESMC-2012 - 8th European Solid Mechanics Conference, Graz, Austria, July 9-13, 2012 978-3-85125-223-1 Fachbereich Medizintechnik und Technomathematik OPUS4-5110 Konferenzveröffentlichung Frotscher, Ralf, frotscher@fh-aachen.de; Raatschen, Hans-Jürgen, raatschen@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Holzapfel, Gerhard A. Effectiveness of the edge-based smoothed finite element method applied to soft biological tissues Graz Verlag d. Technischen Universität Graz 2012 ESMC-2012 - 8th European Solid Mechanics Conference, Graz, Austria, July 9-13, 2012 978-3-85125-223-1 Fachbereich Medizintechnik und Technomathematik OPUS4-4979 Konferenzveröffentlichung Staat, Manfred, m.staat@fh-aachen.de Limit and shakedown analysis under uncertainty 2012 24 Proceedings International Conference on Advances in Computational Mechanics (ACOME) International Conference on Advances in Computational Mechanics (ACOME), August 14-16, 2012, Ho Chi Minh City, Vietnam 837 861 Fachbereich Medizintechnik und Technomathematik OPUS4-4978 Konferenzveröffentlichung Pham, Phu Tinh, ; Nguyen, Thanh Ngoc, ; Staat, Manfred, m.staat@fh-aachen.de FEM based shakedown analysis of hardening structures 2012 12 Proceedings International Conference on Advances in Computational Mechanics (ACOME) International Conference on Advances in Computational Mechanics (ACOME), August 14-16, 2012, Ho Chi Minh City, Vietnam 870 882 Fachbereich Medizintechnik und Technomathematik OPUS4-4977 Konferenzveröffentlichung Tran, Thanh Ngoc, tran@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Eberhardsteiner, J. A primal-dual shakedown analysis of 3D structures using the face-based smoothed finite element method 2012 Proceedings European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Vienna, Austria, September 10-14, 2012 Fachbereich Medizintechnik und Technomathematik OPUS4-4976 Konferenzveröffentlichung Duong, Minh Tuan, duong@fh-aachen.de; Nguyen, Nhu Huynh, ; Staat, Manfred, m.staat@fh-aachen.de Eberhardsteiner, J. Numerical stability enhancement of modeling hyperelastic materials 2012 Proceedings European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Vienna, Austria, September 10-14, 2012 Fachbereich Medizintechnik und Technomathematik OPUS4-4975 Konferenzveröffentlichung Frotscher, Ralf, frotscher@fh-aachen.de; Raatschen, Hans-Jürgen, raatschen@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de Eberhardsteiner, J. Application of an edge-based smoothed finite element method on geometrically non-linear plates of non-linear material 2012 Proceedings European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) 6th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2012) Vienna, Austria, September 10-14, 2012 Fachbereich Medizintechnik und Technomathematik OPUS4-1553 Konferenzveröffentlichung Burgazzi, L., ; Fiorini, F., ; De Magistris, W. (u.a.), ; Lensa, W. von, ; Staat, Manfred, m.staat@fh-aachen.de; Altes, J., Reliability Assessment of Passive Safety Systems New York American Society of Mechanical Engineers 1998 Proceedings of the 6th International Conference on Nuclear Engineering : ICONE : May 10 - 14, 1998, San Diego, Calif. CD-ROM Fachbereich Medizintechnik und Technomathematik OPUS4-300 Konferenzveröffentlichung Tran, Thanh Ngoc, tran@fh-aachen.de; Novacek, V., ; Tolba, R., ; Klinge, U., ; Turquier, F., ; Staat, Manfred, m.staat@fh-aachen.de Experimental and Computational approach to study colorectal anastomosis. ISB2011, Proceedings of the XXIII Congress of the International Society of Biomechanics, Brussels, Belgium, July 3-7, 2011 Summary: This paper presents a methodology to study and understand the mechanics of stapled anastomotic behaviors by combining empirical experimentation and finite element analysis. Performance of stapled anastomosis is studied in terms of leakage and numerical results which are compared to in vitro experiments performed on fresh porcine tissue. Results suggest that leaks occur between the tissue and staple legs penetrating through the tissue. 2011 Fachbereich Medizintechnik und Technomathematik OPUS4-264 Konferenzveröffentlichung Ballmann, J., ; Raatschen, Hans-Jürgen, raatschen@fh-aachen.de; Staat, Manfred, m.staat@fh-aachen.de High stress intensities in focussing zones of waves The propagation of mechanical waves in plates of isotropic elastic material is investigated. After a short introduction to the understanding of focussing of stress waves in a plate with a curved boundary the method of characteristics is applied to a plate of hyperelastic material. Using this method the propagation of acceleration waves is discussed. Based on this a numerical difference scheme is developed for solving initial-boundary-value problems and applied to two examples: propagation of a point disturbance in a homogeneously finitely strained non-linear elastic plate and geometrical focussing in al linear elastic plate. 1985 10.1016/B978-0-444-42520-1.50015-3 Fachbereich Medizintechnik und Technomathematik OPUS4-208 Konferenzveröffentlichung Staat, Manfred, m.staat@fh-aachen.de; Tran, Thanh Ngoc, tran@fh-aachen.de; Pham, Phu Tinh, Limit and shakedown reliability analysis by nonlinear programming 7th International Conference on Reliability of Materials and Structures (RELMAS 2008). June 17 - 20, 2008 ; Saint Petersburg, Russia. pp 354-358. Reprint with corrections in red Introduction Analysis of advanced structures working under extreme heavy loading such as nuclear power plants and piping system should take into account the randomness of loading, geometrical and material parameters. The existing reliability are restricted mostly to the elastic working regime, e.g. allowable local stresses. Development of the limit and shakedown reliability-based analysis and design methods, exploiting potential of the shakedown working regime, is highly needed. In this paper the application of a new algorithm of probabilistic limit and shakedown analysis for shell structures is presented, in which the loading and strength of the material as well as the thickness of the shell are considered as random variables. The reliability analysis problems may be efficiently solved by using a system combining the available FE codes, a deterministic limit and shakedown analysis, and the First and Second Order Reliability Methods (FORM/SORM). Non-linear sensitivity analyses are obtained directly from the solution of the deterministic problem without extra computational costs. 2008 Fachbereich Medizintechnik und Technomathematik OPUS4-217 Konferenzveröffentlichung Tran, Thanh Ngoc, tran@fh-aachen.de; Pham, Phu Tinh, ; Staat, Manfred, m.staat@fh-aachen.de Reliability analysis of shells based on direct plasticity methods Abstracts der CD-Rom Proceedings of the 8th World Congress on Computational Mechanics (WCCM8) and 5th Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2008) 30.06. - 04.07.2008 Venedig, Italien. 2 Seiten Zusammenfassung der Autoren mit graph. Darst. und Literaturverzeichnis 2008 Fachbereich Medizintechnik und Technomathematik OPUS4-207 Konferenzveröffentlichung Staat, Manfred, m.staat@fh-aachen.de; Szelinski, E., ; Heitzer, Michael, Kollapsanalyse von längsfehlerbehafteten Rohren und Behältern Es werden verbesserte Kollapsanalysen von dickwandigen, mit axialen Oberflächenfehlern behafteten Rohren und Behältern vorgeschlagen. 2001 Fachbereich Medizintechnik und Technomathematik OPUS4-206 Konferenzveröffentlichung Staat, Manfred, m.staat@fh-aachen.de; Heitzer, Michael, ; Reinders, H., ; Schubert, F., Einspielen und Ratchetting bei Zug- und Torsionsbelastung: Analyse und Experimente Traglast- und Einspielanalysen sind vereinfachte doch exakte Verfahren der klassischen Plastizitätstheorie, die neben ausreichender Verformbarkeit keine einschränkenden Voraussetzungen beinhalten. Die Vereinfachungen betreffen die Beschaffung der Daten und Modelle für Details der Lastgeschichte und des Stoffverhaltens. Eine FEM-basierte Traglast- und Einspielanalyse für ideal plastisches Material wurde auf ein kinematisch verfestigendes Materialgesetz erweitert und in das Finite Element Programm PERMAS implementiert. In einem einfachen Zug-Torsionsexperiment wurde eine Hohlprobe mit konstanter Torsion und zyklischer Zugbelastung beansprucht, um die neue Implementierung zu verifizieren. Es konnte gezeigt werden, dass die Einspielanalyse gut mit den experimentellen Ergebnissen übereinstimmt. Bei Verfestigung lassen sich wesentlich größere Sicherheiten nachweisen. Dieses Potential bedarf weiterer experimenteller Absicherung. Parallel dazu ist die Eisnpieltheorie auf fortschrittliche Verfestigungsansätze zu erweitern. 2001 Fachbereich Medizintechnik und Technomathematik OPUS4-205 Konferenzveröffentlichung Staat, Manfred, m.staat@fh-aachen.de; Heitzer, Michael, ; Hicken, E. F., LISA - ein europäisches Projekt zur FEM-basierten Traglast- und Einspielanalyse Traglast- und Einspielanalysen sind vereinfachte doch exakte Verfahren der Plastizität, die neben ausreichender Verformbarkeit keine einschränkenden Voraussetzungen beinhalten. Die Vereinfachungen betreffen die Beschaffung der Daten und Modelle für Details der Lastgeschichte und des Stoffverhaltens. Anders als die klassische Behandlung nichtlinearer Probleme der Strukturmechanik führt die Methode auf Optimierungsprobleme. Diese sind bei realistischen FEM-Modellen sehr groß. Das hat die industrielle Anwendung der Traglast- und Einspielanalysen stark verzögert. Diese Situation wird durch das Brite-EuRam Projekt LISA grundlegend geändert. In LISA entsteht auf der Basis des industriellen FEM-Programms PERMAS ein Verfahren zur direkten Berechnung der Tragfähigkeit duktiler Strukturen. Damit kann der Betriebsbereich von Komponenten und Bauwerken auf den plastischen Bereich erweitert werden, ohne den Aufwand gegenüber elastischen Analysen wesentlich zu erhöhen. Die beachtlichen Rechenzeitgewinne erlauben Parameterstudien und die Berechnung von Interaktionsdiagrammen, die einen schnellen Überblick über mögliche Betriebsbereiche vermitteln. Es zeigt sich, daß abhängig von der Komponente und ihren Belastungen teilweise entscheidende Sicherheitsgewinne zur Erweiterung der Betriebsbereiche erzielt werden können. Das Vorgehen erfordert vom Anwender oft ein gewisses Umdenken. Es werden keine Spannungen berechnet, um damit Sicherheit und Lebensdauer zu interpretieren. Statt dessen berechnet man direkt die gesuchte Sicherheit. Der Post-Prozessor wird nur noch zur Modell- und Rechenkontrolle benötigt. Das Vorgehen ist ähnlich der Stabilitätsanalyse (Knicken, Beulen). Durch namhafte industrielle Projektpartner werden Validierung und die Anwendbarkeit auf eine breite Palette technischer Probleme garantiert. Die ebenfalls in LISA entwickelten Zuverlässigkeitsanalysen sind nichlinear erst auf der Basis direkter Verfahren effektiv möglich. Ohne Traglast- und Einspielanalyse ist plastische Strukturoptimierung auch heute kaum durchführbar. Auf die vorgesehenen Erweiterungen der Werkstoffmodellierung für nichtlineare Verfestigung und für Schädigung konnte hier nicht eingegangen werden. Es herrscht ein deutlicher Mangel an Experimenten zum Nachweis der Grenzen zwischen elastischem Einspielen und dem Versagen durch LCF oder durch Ratchetting. 1999 Fachbereich Medizintechnik und Technomathematik OPUS4-204 Konferenzveröffentlichung Lang, H., ; Wirtz, K., ; Heitzer, Michael, ; Staat, Manfred, m.staat@fh-aachen.de; Oettel, R., Zyklische Einspielversuche zur Verifikation von Shakedown-Analysen mittels FEM Im Rahmen von Ermüdungsanalysen ist nachzuweisen, daß die thermisch bedingten fortschreitenden Deformationen begrenzt bleiben. Hierzu ist die Abgrenzung des Shakedown-Bereiches (Einspielen) vom Ratchetting-Bereich (fortschreitende Deformation) von Interesse. Im Rahmen eines EU-geförderten Forschungsvorhabens wurden Experimente mit einem 4-Stab-Modell durchgeführt. Das Experiment bestand aus einem wassergekühlten inneren Rohr und drei isolierten und beheizbaren äußeren Probestäben. Das System wurde durch alternierende Axialkräfte, denen alternierende Temperaturen an den äußeren Stäben überlagert wurden, belastet. Die Versuchsparameter wurden teilweise nach vorausgegangenen Einspielanalysen gewählt. Während der Versuchsdurchführung wurden Temperaturen und Dehnungen zeitabhängig gemessen. Begleitend und nachfolgend zur Versuchsdurchführung wurden die Belastungen und die daraus resultierenden Beanspruchungen nachvollzogen. Bei dieser inkrementellen elasto-plastischen Analyse mit dem Programm ANSYS wurden unterschiedliche Werkstoffmodelle angesetzt. Die Ergebnisse dieser Simulationsberechnung dienen dazu, die Shakedown-Analysen mittels FE-Methode zu verifizieren. 1999 Fachbereich Medizintechnik und Technomathematik