@inproceedings{BallmannRaatschenStaat1985, author = {Ballmann, J. and Raatschen, Hans-J{\"u}rgen and Staat, Manfred}, title = {High stress intensities in focussing zones of waves}, doi = {10.1016/B978-0-444-42520-1.50015-3}, year = {1985}, abstract = {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.}, subject = {Technische Mechanik}, language = {en} } @inproceedings{BhattaraiFrotscherSoraetal.2014, author = {Bhattarai, Aroj and Frotscher, Ralf and Sora, M.-C. and Staat, Manfred}, title = {A 3D finite element model of the female pelvic floor for the reconstruction of urinary incontinence}, 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} } @inproceedings{BurgazziFioriniDeMagistrisetal.1998, author = {Burgazzi, L. and Fiorini, F. and De Magistris, W. (u.a.) and Lensa, W. von and Staat, Manfred and Altes, J.}, title = {Reliability Assessment of Passive Safety Systems}, series = {Proceedings of the 6th International Conference on Nuclear Engineering : ICONE : May 10 - 14, 1998, San Diego, Calif.}, booktitle = {Proceedings of the 6th International Conference on Nuclear Engineering : ICONE : May 10 - 14, 1998, San Diego, Calif.}, publisher = {American Society of Mechanical Engineers}, address = {New York}, year = {1998}, language = {en} } @inproceedings{DuongJungFrotscheretal.2016, author = {Duong, Minh Tuan and Jung, Alexander and Frotscher, Ralf and Staat, Manfred}, title = {A 3D electromechanical FEM-based model for cardiac tissue}, series = {ECCOMAS Congress 2016, VII European Congress on Computational Methods in Applied Sciences and Engineering. Crete Island, Greece, 5-10 June 2016}, booktitle = {ECCOMAS Congress 2016, VII European Congress on Computational Methods in Applied Sciences and Engineering. Crete Island, Greece, 5-10 June 2016}, editor = {Papadrakakis, M.}, pages = {13 S.}, year = {2016}, language = {en} } @inproceedings{DuongStaat2014, author = {Duong, Minh Tuan and Staat, Manfred}, title = {A face-based smoothed finite element method for hyperelastic models and tissue growth}, 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} } @inproceedings{FrotscherDuongStaat2015, author = {Frotscher, Ralf and Duong, Minh Tuan and Staat, Manfred}, title = {Simulating beating cardiomyocytes with electromechanical coupling}, series = {II. International Conference on Biomedical Technology : 28-30 October 2015 Hannover, Germany / T. Lenarz, P. Wriggers (Eds.)}, booktitle = {II. International Conference on Biomedical Technology : 28-30 October 2015 Hannover, Germany / T. Lenarz, P. Wriggers (Eds.)}, organization = {International Conference on Biomedical Technology <2, 2015, Hannover>}, pages = {1 -- 2}, year = {2015}, language = {en} } @inproceedings{FrotscherKochRaatschenetal.2014, author = {Frotscher, Ralf and Koch, Jan-Peter and Raatschen, Hans-J{\"u}rgen and Staat, Manfred}, title = {Evaluation of a computational model for drug action on cardiac tissue}, 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} } @inproceedings{FrotscherStaat2015, author = {Frotscher, Ralf and Staat, Manfred}, title = {Homogenization of a cardiac tissue construct}, series = {CMBE15 : 4th International Conference on Computational \& Mathematical Biomedical Engineering ; 29th June - 1st July 2015 ; {\´E}cole Normale Sup{\´e}rieure de Cachan ; Cachan (Paris), France}, booktitle = {CMBE15 : 4th International Conference on Computational \& Mathematical Biomedical Engineering ; 29th June - 1st July 2015 ; {\´E}cole Normale Sup{\´e}rieure de Cachan ; Cachan (Paris), France}, editor = {Nithiarasu, Perumal}, publisher = {CMBE}, address = {[s.l.]}, issn = {2227-9385}, pages = {645 -- 648}, year = {2015}, language = {en} } @article{GorissenStaatLaack2012, author = {Gorissen, P. and Staat, Manfred and Laack, Walter van}, title = {Experimentelle Kraftmessungen als Beitrag zur Wirksamkeitsbeurteilung von Schienbeinschonern im Fußballsport}, series = {OUP Zeitschrift f{\"u}r die orthop{\"a}dische und unfallchirurgische Praxis}, volume = {1}, journal = {OUP Zeitschrift f{\"u}r die orthop{\"a}dische und unfallchirurgische Praxis}, number = {1}, publisher = {Deutscher {\"A}rzte-Verlag}, address = {K{\"o}ln}, issn = {2193-5785}, doi = {10.3238/oup.2012.0010-0015}, pages = {10 -- 15}, year = {2012}, abstract = {Diese Studie besch{\"a}ftigte sich mit der D{\"a}mpfungswirkung von Schienbeinschonern, wie sie beim Fußball zum Einsatz kommen. Sie wurde mit Hilfe eines Pendelhammers durchgef{\"u}hrt, der verschiedene Aufschlagkr{\"a}fte auf die Schoner erm{\"o}glichte. Dabei wurde deutlich, dass Schienbeinschoner die beste Wirkung bei Maximalkr{\"a}ften unterhalb von 5kN erreichen k{\"o}nnen, dass bei gr{\"o}ßerer Belastung allerdings Verbesserungsbedarf besteht. Hierf{\"u}r konnte, u.a. durch den Einsatz neuer Materialien, ein guter Ansatzpunkt im „ad{\"a}quaten Zusammenspiel von Schale und Polsterung" der Schoner gefunden werden. Die Untersuchung hat weiterhin gezeigt, dass zumindest teilweise eine deutliche Verbesserung der D{\"a}mpfungswirkung der Schienbeinschoner in den letzten Jahren erreicht werden konnte.}, subject = {Fußball}, language = {de} } @inproceedings{HeitzerStaat2000, author = {Heitzer, M. and Staat, Manfred}, title = {Direct FEM approach to design-by-analysis of pressurized components}, year = {2000}, abstract = {Abstracts of the ACHEMA 2000 - International Meeting on Chemical Engineering, Environmental Protection and Biotechnology, May 22 - 27, 2000. Frankfurt am Main. Achema 2000 : special edition / Linde. [Ed.: Linde AG. Red.: Volker R. Leski]. - Wiesbaden : Linde AG, 2000. - 56 p. : Ill., . - pp: 79 - 81}, subject = {Finite-Elemente-Methode}, language = {en} } @inproceedings{JungFrotscherStaat2018, author = {Jung, Alexander and Frotscher, Ralf and Staat, Manfred}, title = {Electromechanical model of hiPSC-derived ventricular cardiomyocytes cocultured with fibroblasts}, series = {6th European Conference on Computational Mechanics (ECCM 6), 7th European Conference on Computational Fluid Dynamics (ECFD 7), 11-15 June 2018, Glasgow, UK}, booktitle = {6th European Conference on Computational Mechanics (ECCM 6), 7th European Conference on Computational Fluid Dynamics (ECFD 7), 11-15 June 2018, Glasgow, UK}, pages = {11 Seiten}, year = {2018}, abstract = {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.}, language = {en} } @inproceedings{JungStaatMueller2014, author = {Jung, Alexander and Staat, Manfred and M{\"u}ller, Wolfram}, title = {Optimization of the flight style in ski jumping}, 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 = {799 -- 810}, year = {2014}, language = {en} } @article{KuehnHaugnerStaatetal.2004, author = {K{\"u}hn, Raoul-Roman and Haugner, Werner and Staat, Manfred and Sponagel, Stefan}, title = {A Two Phase Mixture Model based on Bone Observation}, year = {2004}, abstract = {An optimization method is developed to describe the mechanical behaviour of the human cancellous bone. The method is based on a mixture theory. A careful observation of the behaviour of the bone material leads to the hypothesis that the bone density is controlled by the principal stress trajectories (Wolff's law). The basic idea of the developed method is the coupling of a scalar value via an eigenvalue problem to the principal stress trajectories. On the one hand this theory will permit a prediction of the reaction of the biological bone structure after the implantation of a prosthesis, on the other hand it may be useful in engineering optimization problems. An analytical example shows its efficiency.}, subject = {Knochen}, language = {en} } @inproceedings{LangWirtzHeitzeretal.1999, author = {Lang, H. and Wirtz, K. and Heitzer, Michael and Staat, Manfred and Oettel, R.}, title = {Zyklische Einspielversuche zur Verifikation von Shakedown-Analysen mittels FEM}, year = {1999}, abstract = {Im Rahmen von Erm{\"u}dungsanalysen 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-gef{\"o}rderten Forschungsvorhabens wurden Experimente mit einem 4-Stab-Modell durchgef{\"u}hrt. Das Experiment bestand aus einem wassergek{\"u}hlten inneren Rohr und drei isolierten und beheizbaren {\"a}ußeren Probest{\"a}ben. Das System wurde durch alternierende Axialkr{\"a}fte, denen alternierende Temperaturen an den {\"a}ußeren St{\"a}ben {\"u}berlagert wurden, belastet. Die Versuchsparameter wurden teilweise nach vorausgegangenen Einspielanalysen gew{\"a}hlt. W{\"a}hrend der Versuchsdurchf{\"u}hrung wurden Temperaturen und Dehnungen zeitabh{\"a}ngig gemessen. Begleitend und nachfolgend zur Versuchsdurchf{\"u}hrung 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.}, subject = {Einspielen }, language = {de} } @article{LeversStaatLaack2011, author = {Levers, A. and Staat, Manfred and Laack, Walter van}, title = {Analyse der Langzeitwirkung der MBST® KernspinResonanzTherapie bei Gonarthrose}, year = {2011}, abstract = {Originalausgabe: Orthop{\"a}dische Praxis Jg. 47. 2011 H. 11; S. 536-543. Mit freundlicher Genehmigung des Verlags Zusammenfassung: Auf der Basis von Patientenabfragen mittels Fragebogen zum Schmerzempfinden und zur Einschr{\"a}nkung bei Aktivit{\"a}ten des allt{\"a}glichen Lebens wird die Langzeitwirkung der MBST® KernspinResonanz-Therapie bei Gonarthrose untersucht. An der Studie nahmen 39 Patienten teil, bei denen die Therapie bis zu vier Jahre zur{\"u}ckliegt. Neben einer Gesamtbetrachtung wird der Erfolg auch in Abh{\"a}ngigkeit von Alter, Geschlecht und sportlicher Aktivit{\"a}t analysiert. Insgesamt weist die Studie auf eine anhaltende Verbesserung des Gesundheitszustands mit zum Teil deutlicher Schmerzlinderung auch noch nach vier Jahren hin, jedoch mit einer leichten Schmerzzunahme gegen Ende des Untersuchungszeitraums von vier Jahren. Eine tendenziell positivere Wirkung bei Frauen, {\"a}lteren Menschen oder auch sportlich nicht-aktiven Patienten l{\"a}sst auf eine m{\"o}gliche Beeinflussung des Erfolgs der Therapie durch ({\"U}ber-)Belastung im Alltag schließen. Ein zus{\"a}tzlich positiver Effekt der Therapie auf die Knochendichte ist ebenfalls denkbar, dies bleibt jedoch offen.}, subject = {Kniegelenkarthrose}, language = {de} } @article{Staat2004, author = {Staat, Manfred}, title = {Plastic collapse analysis of longitudinally flawed pipes and vessels}, year = {2004}, abstract = {Improved collapse loads of thick-walled, crack containing pipes and vessels are suggested. Very deep cracks have a residual strength which is better modelled by a global limit load. In all burst tests, the ductility of pressure vessel steels was sufficiently high whereby the burst pressure could be predicted by limit analysis with no need to apply fracture mechanics. The relative prognosis error increases however, for long and deep defects due to uncertainties of geometry and strength data.}, subject = {Druckbeh{\"a}lter}, language = {en} } @article{Staat2001, author = {Staat, Manfred}, title = {Cyclic plastic deformation tests to verify FEM-based shakedown analyses}, year = {2001}, abstract = {Fatigue analyses are conducted with the aim of verifying that thermal ratcheting is limited. To this end it is important to make a clear distintion between the shakedown range and the ratcheting range (continuing deformation). As part of an EU-supported research project, experiments were carried out using a 4-bar model. The experiment comprised a water-cooled internal tube, and three insulated heatable outer test bars. The system was subjected to alternating axial forces, superimposed with alternating temperatures at the outer bars. The test parameters were partly selected on the basis of previous shakedown analyses. During the test, temperatures and strains were measured as a function of time. The loads and the resulting stresses were confirmed on an ongoing basis during performance of the test, and after it. Different material models were applied for this incremental elasto-plastic analysis using the ANSYS program. The results of the simulation are used to verify the FEM-based shakedown analysis.}, subject = {Materialerm{\"u}dung}, language = {en} } @article{Staat2005, author = {Staat, Manfred}, title = {Local and global collapse pressure of longitudinally flawed pipes and cylindrical vessels}, year = {2005}, abstract = {Limit loads can be calculated with the finite element method (FEM) for any component, defect geometry, and loading. FEM suggests that published long crack limit formulae for axial defects under-estimate the burst pressure for internal surface defects in thick pipes while limit loads are not conservative for deep cracks and for pressure loaded crack-faces. Very deep cracks have a residual strength, which is modelled by a global collapse load. These observations are combined to derive new analytical local and global collapse loads. The global collapse loads are close to FEM limit analyses for all crack dimensions.}, subject = {Finite-Elemente-Methode}, language = {en} } @article{Staat2005, author = {Staat, Manfred}, title = {Direct finite element route for design-by-analysis of pressure components}, year = {2005}, abstract = {In the new European standard for unfired pressure vessels, EN 13445-3, there are two approaches for carrying out a Design-by-Analysis that cover both the stress categorization method (Annex C) and the direct route method (Annex B) for a check against global plastic deformation and against progressive plastic deformation. This paper presents the direct route in the language of limit and shakedown analysis. This approach leads to an optimization problem. Its solution with Finite Element Analysis is demonstrated for mechanical and thermal actions. One observation from the examples is that the so-called 3f (3Sm) criterion fails to be a reliable check against progressive plastic deformation. Precise conditions are given, which greatly restrict the applicability of the 3f criterion.}, subject = {Einspielen }, language = {en} } @article{Staat2003, author = {Staat, Manfred}, title = {Shakedown and ratchetting under tension-torsion loadings: analysis and experiments}, year = {2003}, abstract = {Structural design analyses are conducted with the aim of verifying the exclusion of ratchetting. To this end it is important to make a clear distinction between the shakedown range and the ratchetting range. The performed experiment comprised a hollow tension specimen which was subjected to alternating axial forces, superimposed with constant moments. First, a series of uniaxial tests has been carried out in order to calibrate a bounded kinematic hardening rule. The load parameters have been selected on the basis of previous shakedown analyses with the PERMAS code using a kinematic hardening material model. It is shown that this shakedown analysis gives reasonable agreement between the experimental and the numerical results. A linear and a nonlinear kinematic hardening model of two-surface plasticity are compared in material shakedown analysis.}, subject = {Einspielen }, language = {en} }