@article{JungMuellerStaat2018,
  author    = {Jung, Alexander and M{\"u}ller, Wolfram and Staat, Manfred},
  title     = {Wind and fairness in ski jumping: A computer modelling analysis},
  series = {Journal of Biomechanics},
  journal   = {Journal of Biomechanics},
  number    = {75},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0021-9290},
  doi       = {10.1016/j.jbiomech.2018.05.001},
  pages     = {147 -- 153},
  year      = {2018},
  abstract  = {Wind is closely associated with the discussion of fairness in ski jumping. To counter-act its influence on the jump length, the International Ski Federation (FIS) has introduced a wind compensation approach. We applied three differently accurate computer models of the flight phase with wind (M1, M2, and M3) to study the jump length effects of various wind scenarios. The previously used model M1 is accurate for wind blowing in direction of the flight path, but inaccuracies are to be expected for wind directions deviating from the tangent to the flight path. M2 considers the change of airflow direction, but it does not consider the associated change in the angle of attack of the skis which additionally modifies drag and lift area time functions. M3 predicts the length effect for all wind directions within the plane of the flight trajectory without any mathematical simplification. Prediction errors of M3 are determined only by the quality of the input data: wind velocity, drag and lift area functions, take-off velocity, and weight. For comparing the three models, drag and lift area functions of an optimized reference jump were used. Results obtained with M2, which is much easier to handle than M3, did not deviate noticeably when compared to predictions of the reference model M3. Therefore, we suggest to use M2 in future applications. A comparison of M2 predictions with the FIS wind compensation system showed substantial discrepancies, for instance: in the first flight phase, tailwind can increase jump length, and headwind can decrease it; this is opposite of what had been anticipated before and is not considered in the current wind compensation system in ski jumping.},
  language  = {en}
}
@article{StaatBallmann1988,
  author    = {Staat, Manfred and Ballmann, J.},
  title     = {Wave Propagation and Focussing in Plates},
  series = {Impact loading and dynamic behaviour of materials : Papers presented at the International Conference on Impact Loading and Dynamic Behaviour of Materials, Vol. 2 / Chiem, C. Y.; Kunze, L. (u.a.) [eds]},
  journal   = {Impact loading and dynamic behaviour of materials : Papers presented at the International Conference on Impact Loading and Dynamic Behaviour of Materials, Vol. 2 / Chiem, C. Y.; Kunze, L. (u.a.) [eds]},
  publisher = {DGM Informationsges.},
  address   = {Oberursel},
  year      = {1988},
  language  = {en}
}
@article{UllrichGrottkeRossaintetal.2010,
  author    = {Ullrich, Sebastian and Grottke, Oliver and Rossaint, Rolf and Staat, Manfred and Deserno, Thomas M. and Kuhlen, Torsten},
  title     = {Virtual Needle Simulation with Haptics for Regional Anaesthesia},
  pages     = {1 -- 3},
  year      = {2010},
  language  = {en}
}
@article{BhattaraiHorbachStaatetal.2022,
  author    = {Bhattarai, Aroj and Horbach, Andreas and Staat, Manfred and Kowalczyk, Wojciech and Tran, Thanh Ngoc},
  title     = {Virgin passive colon biomechanics and a literature review of active contraction constitutive models},
  series = {Biomechanics},
  volume    = {2},
  journal   = {Biomechanics},
  number    = {2},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2673-7078},
  doi       = {10.3390/biomechanics2020013},
  pages     = {138 -- 157},
  year      = {2022},
  abstract  = {The objective of this paper is to present our findings on the biomechanical aspects of the virgin passive anisotropic hyperelasticity of the porcine colon based on equibiaxial tensile experiments. Firstly, the characterization of the intestine tissues is discussed for a nearly incompressible hyperelastic fiber-reinforced Holzapfel-Gasser-Ogden constitutive model in virgin passive loading conditions. The stability of the evaluated material parameters is checked for the polyconvexity of the adopted strain energy function using positive eigenvalue constraints of the Hessian matrix with MATLAB. The constitutive material description of the intestine with two collagen fibers in the submucosal and muscular layer each has been implemented in the FORTRAN platform of the commercial finite element software LS-DYNA, and two equibiaxial tensile simulations are presented to validate the results with the optical strain images obtained from the experiments. Furthermore, this paper also reviews the existing models of the active smooth muscle cells, but these models have not been computationally studied here. The review part shows that the constitutive models originally developed for the active contraction of skeletal muscle based on Hill's three-element model, Murphy's four-state cross-bridge chemical kinetic model and Huxley's sliding-filament hypothesis, which are mainly used for arteries, are appropriate for numerical contraction numerical analysis of the large intestine.},
  language  = {en}
}
@article{TranKreissigVuetal.2008,
  author    = {Tran, Thanh Ngoc and Kreißig, R. and Vu, Duc Khoi and Staat, Manfred},
  title     = {Upper bound limit and shakedown analysis of shells using the exact Ilyushin yield surface},
  series = {Computer \& Structures. 86 (2008)},
  journal   = {Computer \& Structures. 86 (2008)},
  isbn      = {0045-7949},
  pages     = {1683 -- 1695},
  year      = {2008},
  language  = {en}
}
@incollection{TranStaat2015,
  author    = {Tran, Thanh Ngoc and Staat, Manfred},
  title     = {Uncertainty multimode failure and shakedown analysis of shells},
  series = {Direct methods for limit and shakedown analysis of structures / eds. Paolo Fuschi ...},
  booktitle = {Direct methods for limit and shakedown analysis of structures / eds. Paolo Fuschi ...},
  publisher = {Springer},
  address   = {Cham},
  isbn      = {978-3-319-12927-3 (print) ; 978-3-319-12928-0 (online)},
  doi       = {10.1007/978-3-319-12928-0_14},
  pages     = {279 -- 298},
  year      = {2015},
  abstract  = {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.},
  language  = {en}
}
@inproceedings{TranStaat2014,
  author    = {Tran, Thanh Ngoc and Staat, Manfred},
  title     = {Uncertain multimode failure and limit analysis of shells},
  series = {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},
  booktitle = {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},
  editor    = {Onate, E.},
  organization    = {World Congress on Computational Mechanics <11, 2014, Barcelona>},
  pages     = {1 -- 12},
  year      = {2014},
  language  = {en}
}
@incollection{FrotscherStaat2018,
  author    = {Frotscher, Ralf and Staat, Manfred},
  title     = {Towards Patient-Specific Computational Modeling of hiPS-Derived Cardiomyocyte Function and Drug Action},
  series = {Biological, Physical and Technical Basics of Cell Engineering},
  booktitle = {Biological, Physical and Technical Basics of Cell Engineering},
  editor    = {Artmann, Gerhard and Temiz Artmann, Ayseg{\"u}l and Zhubanova, Azhar A. and Digel, Ilya},
  publisher = {Springer},
  address   = {Singapore},
  isbn      = {978-981-10-7904-7},
  doi       = {10.1007/978-981-10-7904-7_10},
  pages     = {233 -- 250},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{CiobanuStaatRahimi2008,
  author    = {Ciobanu, Octavian and Staat, Manfred and Rahimi, Alireza},
  title     = {The use of open source software in biomechanical finite element analysis},
  series = {Buletinul Institutului Politehnic din Ia{\c{s}}i / Universitatea Tehnică Gh. Asachi, Ia{\c{s}}i Secţia 5, Construcţii de ma{\c{s}}ini = Machine construction = Bulletin of the Polytechnic Institute of Jassy = Izvestija Jasskogo Politechničeskogo Instituta},
  volume    = {54},
  journal   = {Buletinul Institutului Politehnic din Ia{\c{s}}i / Universitatea Tehnică Gh. Asachi, Ia{\c{s}}i Secţia 5, Construcţii de ma{\c{s}}ini = Machine construction = Bulletin of the Polytechnic Institute of Jassy = Izvestija Jasskogo Politechničeskogo Instituta},
  number    = {7/8},
  issn      = {1011-2855},
  pages     = {213 -- 220},
  year      = {2008},
  language  = {en}
}
@inproceedings{StaatHeitzer2002,
  author    = {Staat, Manfred and Heitzer, Michael},
  title     = {The restricted influence of kinematic hardening on shakedown loads},
  year      = {2002},
  abstract  = {Structural design analyses are conducted with the aim of verifying the exclusion of ratcheting. To this end it is important to make a clear distinction between the shakedown range and the ratcheting range. In cyclic plasticity more sophisticated hardening models have been suggested in order to model the strain evolution observed in ratcheting experiments. The hardening models used in shakedown analysis are comparatively simple. It is shown that shakedown analysis can make quite stable predictions of admissible load ranges despite the simplicity of the underlying hardening models. A linear and a nonlinear kinematic hardening model of two-surface plasticity are compared in material shakedown analysis. Both give identical or similar shakedown ranges. Structural shakedown analyses show that the loading may have a more pronounced effect than the hardening model.},
  subject      = {Biomedizinische Technik},
  language  = {en}
}
@book{StaatDigelTrzewiketal.2024,
  author    = {Staat, Manfred and Digel, Ilya and Trzewik, J{\"u}rgen and Sielemann, Stefanie and Erni, Daniel and Zylka, Waldemar},
  title     = {Symposium Proceedings; 4th YRA MedTech Symposium 2024 : February 1 / 2024 / FH Aachen},
  publisher = {Universit{\"a}t Duisburg-Essen},
  address   = {Duisburg},
  organization    = {MedTech Symposium},
  isbn      = {978-3-940402-65-3},
  doi       = {10.17185/duepublico/81475},
  pages     = {40 Seiten},
  year      = {2024},
  language  = {en}
}
@book{StaatErni2019,
  author    = {Staat, Manfred and Erni, Daniel},
  title     = {Symposium Proceedings; 3rd YRA MedTech Symposium 2019: May 24 / 2019 / FH Aachen},
  publisher = {Universit{\"a}t Duisburg-Essen},
  address   = {Duisburg},
  organization    = {MedTech Symposium},
  isbn      = {978-3-940402-22-6},
  doi       = {10.17185/duepublico/48750},
  pages     = {49 Seiten},
  year      = {2019},
  language  = {en}
}
@article{HacklAndermahrStaatetal.2017,
  author    = {Hackl, M. and Andermahr, J. and Staat, Manfred and Bremer, I. and Borggrefe, J. and Prescher, A. and M{\"u}ller, L. P. and Wegmann, K.},
  title     = {Suture button reconstruction of the central band of the interosseous membrane in Essex-Lopresti lesions: a comparative biomechanical investigation},
  series = {The Journal of Hand Surgery (European Volume)},
  volume    = {42},
  journal   = {The Journal of Hand Surgery (European Volume)},
  number    = {4},
  publisher = {Sage},
  address   = {London},
  issn      = {2043-6289 (Online)},
  doi       = {10.1177/1753193416665943},
  pages     = {370 -- 376},
  year      = {2017},
  language  = {en}
}
@article{BhattaraiJabbariAndingetal.2018,
  author    = {Bhattarai, Aroj and Jabbari, Medisa and Anding, Ralf and Staat, Manfred},
  title     = {Surgical treatment of vaginal vault prolapse using different prosthetic mesh implants: a finite element analysis},
  series = {tm - Technisches Messen},
  volume    = {85},
  journal   = {tm - Technisches Messen},
  number    = {5},
  publisher = {De Gruyter},
  address   = {Berlin},
  issn      = {2196-7113},
  doi       = {10.1515/teme-2017-0115},
  pages     = {331 -- 342},
  year      = {2018},
  abstract  = {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 {\"a}ltere, mehrgeb{\"a}hrende Frauen leiden h{\"a}ufiger an einem Scheidenvorfall nach einer Hysterektomie aufgrund der schwachen Unterst{\"u}tzung durch laxe apikale B{\"a}nder. Es wird angenommen, dass eine verringerte Menge an {\"O}strogen und Progesteron im h{\"o}heren Alter das Kollagen umformt, wodurch die Gewebesteifigkeit reduziert wird. Die Sakrokolpopexie ist eine offene oder laparoskopische Operation, die mit prothetischen Netzimplantaten durchgef{\"u}hrt wird, um laxe B{\"a}nder zu ersetzen. Y-f{\"o}rmige 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 w{\"a}hrend des Valsalva-Man{\"o}vers mit geschw{\"a}chtem Gewebe durchgef{\"u}hrt, das durch eine reduzierte Gewebesteifigkeit modelliert wird. Die Gewebe werden als inkompressible, isotrop hyperelastische Materialien modelliert, w{\"a}hrend die Netze entweder als orthotrope linear elastische oder als isotrope hyperlastische Materialien modelliert werden. Die Positionen des Vaginalstumpfs, der Blase und der Harnr{\"o}hrenachse werden anhand der Pubococcygeallinie aus der Ruhelage, f{\"u}r den Prolaps und nach der Reparatur unter Verwendung der drei Netze berechnet. Aufgrund der Netzmechanik und der Netzporenverformung bietet das DynaMesh mit regelm{\"a}ßigen rechteckigen Netzporen eine bessere mechanische Unterst{\"u}tzung und eine Neupositionierung des Scheidengew{\"o}lbes, der Blase und der Urethraachse als Gynemesh und Ultrapro mit unregelm{\"a}ßigen hexagonalen Netzporen.},
  language  = {en}
}
@article{StaatHeitzer1999,
  author    = {Staat, Manfred and Heitzer, M.},
  title     = {Structural Reliability Analysis of Elasto-Plastic Structures},
  series = {Safety and reliability : proceedings of ESREL '99, the Tenth European Conference on Safety and Reliability, Munich-Garching, Germany, 13 - 17 September 1999 / Schu{\"e}ller, G. I.; Kafka, P. [eds]},
  journal   = {Safety and reliability : proceedings of ESREL '99, the Tenth European Conference on Safety and Reliability, Munich-Garching, Germany, 13 - 17 September 1999 / Schu{\"e}ller, G. I.; Kafka, P. [eds]},
  publisher = {Balkema},
  address   = {Rotterdam},
  isbn      = {90-5809-109-0},
  pages     = {513 -- 518},
  year      = {1999},
  language  = {en}
}
@article{FrotscherStaat2014,
  author    = {Frotscher, Ralf and Staat, Manfred},
  title     = {Stresses produced by different textile mesh implants in a tissue equivalent},
  series = {BioNanoMaterials},
  volume    = {15},
  journal   = {BioNanoMaterials},
  number    = {1-2},
  publisher = {De Gruyter},
  address   = {Berlin},
  issn      = {2191-4672 (E-Journal); 2193-066X (E-Journal); 0011-8656 (Print); 1616-0177 (Print); 2193-0651 (Print)},
  doi       = {10.1515/bnm-2014-0003},
  pages     = {25 -- 30},
  year      = {2014},
  abstract  = {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.},
  language  = {en}
}
@inproceedings{StaatTran2022,
  author    = {Staat, Manfred and Tran, Ngoc Trinh},
  title     = {Strain based brittle failure criteria for rocks},
  series = {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},
  booktitle = {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},
  publisher = {Nha xuat ban Khoa hoc tu nhien va Cong nghe (Verlag Naturwissenschaft und Technik)},
  address   = {Hanoi},
  isbn      = {978-604-357-084-7},
  pages     = {500 -- 509},
  year      = {2022},
  abstract  = {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.},
  language  = {en}
}
@article{Staat2002,
  author    = {Staat, Manfred},
  title     = {Some Achievements of the European Project LISA for FEM Based Limit and Shakedown Analysis},
  series = {Computational mechanics : developments and applications, 2002 : presented at the 2002 ASME Pressure Vessels and Piping Conference, Vancouver, British Columbia, Canada, August 5 - 9. / Badie, N. [ed]},
  journal   = {Computational mechanics : developments and applications, 2002 : presented at the 2002 ASME Pressure Vessels and Piping Conference, Vancouver, British Columbia, Canada, August 5 - 9. / Badie, N. [ed]},
  publisher = {American Society of Mechanical Engineers},
  address   = {New York},
  isbn      = {0791846520},
  pages     = {177 -- 185},
  year      = {2002},
  language  = {en}
}
@article{StaatBaroudTopcuetal.2008,
  author    = {Staat, Manfred and Baroud, G. and Topcu, M. and Sponagel, Stefan},
  title     = {Soft Materials in Technology and Biology - Characteristics, Properties, and Parameter Identification},
  series = {Bioengineering in Cell and Tissue Research / Artmann, Gerhard M. ; Chien, Shu (Eds.)},
  journal   = {Bioengineering in Cell and Tissue Research / Artmann, Gerhard M. ; Chien, Shu (Eds.)},
  publisher = {Springer},
  address   = {Berlin},
  isbn      = {978-3-540-75408-4},
  pages     = {253 -- 315},
  year      = {2008},
  language  = {en}
}
@inproceedings{StaatDuong2016,
  author    = {Staat, Manfred and Duong, Minh Tuan},
  title     = {Smoothed Finite Element Methods for Nonlinear Solid Mechanics Problems: 2D and 3D Case Studies},
  series = {Proceedings of the National Science and Technology Conference on Mechanical - Transportation Engineering (NSCMET 2016), 13th October 2016, Hanoi, Vietnam, Vol.2},
  booktitle = {Proceedings of the National Science and Technology Conference on Mechanical - Transportation Engineering (NSCMET 2016), 13th October 2016, Hanoi, Vietnam, Vol.2},
  pages     = {440 -- 445},
  year      = {2016},
  abstract  = {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.},
  language  = {en}
}