Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Übergeordneter Titel Übergeordneter Titel Band Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Konferenzname Heftnummer Erste Seite Letzte Seite URN DOI Institute
OPUS4-2222 Konferenzveröffentlichung Daryusi, Ali FEM-Spannungsanalyse an schräggebohrtem Wellenabsatz Düsseldorf VDI Verlag 2016 5 978-3-18-092287-4 235 239 Fakultät Maschinenbau und Verfahrenstechnik (M+V)
OPUS4-1426 unpublished Daryusi, Ali FEM-Analyse der Spannungsspitzen von torsionsbelasteten Wellen mit mehreren Längs- und Quernuten zur Überprüfung der Ansätze von Okubo und Neuber 2015 16 Dresdner Maschinenelemente Kolloquium – DMK 2015 2015 978-3-95908-030-9 461 477 Fakultät Maschinenbau und Verfahrenstechnik (M+V)
OPUS4-1630 Konferenzveröffentlichung Daryusi, Ali; Lacher, Janosch FEM-Untersuchung zur Entlastung von Durchdringungskerben an Getriebewellen Magdeburg Otto-von-Guericke-Universität, Fakultät für Maschinenbau 2015 9 KT 2015 : Tagungsband : 13. Gemeinsames Kolloquium Konstruktionstechnik 2015, 8. und 9. Oktober in Clausthal, Produktentwicklung zur Qualitätssicherung 978-3-944722-30-6 267 276 Fakultät Maschinenbau und Verfahrenstechnik (M+V)
OPUS4-3681 Dissertation oder Habilitation Jilg, Andreas Development and implementation of a cyclic plasticity model with thermal softening for hot work tool steel Hot working tools are subjected to complex thermal and mechanical loads during service. Locally, the stresses can exceed the material's yield strength in highly loaded areas. During production, this causes cyclic plastic deformation and thus thermomechanical fatigue, which can significantly shorten the lifetime of hot working tools. To sustain this high loads, the hot working tools are typically made of tempered martensitic hot work tool steels. While the annealing temperatures of the tool steels usually lie in the range of 400 to 600 °C, the steels may experience even higher temperatures during hot working, resulting in softening of the material due to changes in microstructure. Therefore, the temperature-dependent cyclic mechanical properties of the frequently used hot work tool steel 1.2367 (X38CrMoV5-3) after tempering are investigated in this work. To this end, hardness measurements are performed. Furthermore, the Institute of Forming Technology and Machines (IFUM) provides test results from cyclic tests at temperatures ranging from 20 °C (room temperature) to 650 °C. To describe the observed time- and temperature-dependent softening during tempering, a kinetic model for the evolution of the mean size of secondary carbides based on Ostwald ripening is developed. In addition, both mechanism-based and phenomenological relationships for the cyclic mechanical properties of the Ramberg- Osgood model depending on carbide size and temperature are proposed. The stress-strain hysteresis loops measured at different temperatures and after different heat treatments can be well described with the proposed kinetic and mechanical model. Furthermore, the model is suitable for integration in advanced mechanism-based lifetime models. However, since the Ramberg-Osgood model is not suitable for finite element implementation, a temperature-dependent incremental cyclic plasticity model is presented as well. Thus, softening due to particle coarsening can be applied in the finite element method (FEM). Therefore, a kinetic model is coupled with a cyclic plasticity model including kinematic hardening. The plasticity model is implemented via subroutines in the finite element program ABAQUS for implicit integration (subroutine called UMAT) and explicit integration (subroutine called VUMAT). The implemented model is used for the simulation of an exemplary hot working process to assess the effects of softening due to particle coarsening. It shows that the thermal softening at high temperatures, which occur over a long time at a mechanically highly loaded area, has a great influence. If this influence is not considered in tool design, an unexpected tool failure might occur bringing the production to a standstill. 2019 104 10.25673/25393 Fakultät Maschinenbau und Verfahrenstechnik (M+V)
OPUS4-2291 Konferenzveröffentlichung Mayer, Andreas; Mayer, Elena; Mayer, Markus; Jäger, Philipp M.; Ruile, Werner; Bleyl, Ingo; Wagner, Karl Full 2D-FEM calculations of third-order intermodulations in SAW devices In a recent paper it has been shown that the effective nonlinear constant which is used in a P-Matrix approach to describe third-order intermodulation (IMD3) in surface acoustic wave (SAW) devices can be obtained from finite element (FEM) calculations of a periodic cell using nonlinear tensor data [1]. In this paper we extend this FEM calculation and show that the IMD3 of an infinite periodic array of electrodes on a piezoelectric substrate can be directly simulated in the sagittal plane. This direct approach opens the way for a FEM based simulation of nonlinearities for finite and generalized structures avoiding the simplifications of phenomenological approaches. 2016 4 Ultrasonic Symposium 10.1109/ULTSYM.2016.7728469 Fakultät Betriebswirtschaft und Wirtschaftsingenieurwesen (B+W)
OPUS4-1436 unpublished Mayer, Andreas; Mayer, Elena; Mayer, Markus; Jäger, Philipp M.; Ruile, Werner; Bleyl, Ingo; Wagner, Karl Effective Nonlinear Constants for SAW Devices from FEM Calculations 2015 4 Proceedings of the 2015 IEEE Ultrasonics Symposium 10.1109/ULTSYM.2015.0055. Fakultät Betriebswirtschaft und Wirtschaftsingenieurwesen (B+W)
OPUS4-3551 Referierter Artikel Metzger, Mario; Seifert, Thomas A Mechanism-Based Model for LCF/HCF and TMF/HCF Life Prediction: Multiaxial Formulation, Finite-Element Implementation and Applicationto Cast Iron In this paper, the multiaxial formulation of a mechanism-based model for fatigue life prediction is presented whichcan be applied to low-cycle fatigue (LCF) and thermomechanical fatigue (TMF) problems in which high-cycle fa-tigue loadings are superimposed. The model assumes that crack growth is the lifetime limiting mechanism and thatthe crack advance in a loading cycleda/dNcorrelates with the cyclic crack-tip opening displacement ΔCTOD.The multiaxial formulation makes use of fracture mechanics solutions and thus, does not need additional modelparameters quantifying the effect of the multiaxiality. Furthermore, the model includes contributions of HCF on ΔCTODand assesses the effect of the direction of the HCF loadings with respect to LCF or TMF loadings inthe life prediction. The model is implemented into the finite-element program ABAQUS. It is applied to predictthe fatigue life of a thermomechanically loaded notched specimen that should represent the situation between theinlet and outlet bore holes of cylinder heads. A good correlation of the predicted and the measured fatigue lives isobtained. Magdeburg 2012 10 TECHNISCHE MECHANIK 32 2-5 435 445 urn:nbn:de:0011-n-2364596 Fakultät Maschinenbau und Verfahrenstechnik (M+V)
OPUS4-1820 Referierter Artikel Metzger, Mario; Seifert, Thomas On the exploitation of Armstrong-Frederik type nonlinear kinematic hardening in the numerical integration and finite-element implementation of pressure dependent plasticity models In this paper, an unconditionally stable algorithm for the numerical integration and finite-element implementation of a class of pressure dependent plasticity models with nonlinear isotropic and kinematic hardening is presented. Existing algorithms are improved in the sense that the number of equations to be solved iteratively is significantly reduced. This is achieved by exploitation of the structure of Armstrong-Frederik-type kinematic hardening laws. The consistent material tangent is derived analytically and compared to the numerically computed tangent in order to validate the implementation. The performance of the new algorithm is compared to an existing one that does not consider the possibility of reducing the number of unknowns to be iterated. The algorithm is used to implement a time and temperature dependent cast iron plasticity model, which is based on the pressure dependent Gurson model, in the finite-element program ABAQUS. The implementation is applied to compute stresses and strains in a large-scale finite-element model of a three cylinder engine block. This computation proofs the applicability of the algorithm in industrial practice that is of interest in applied sciences. Berlin und Heidelberg Springer 2013 9 Computational Mechanics 52 3 515 524 10.1007/s00466-012-0828-1 Fakultät Maschinenbau und Verfahrenstechnik (M+V)
OPUS4-1881 Referierter Artikel Metzger, Mario; Seifert, Thomas; Schweizer, Christoph Does the cyclic J-integral ΔJ describe the crack-tip opening displacement in the presence of crack closure? In this paper, the correlation of the cyclic J-integral, ΔJ, and the cyclic crack-tip opening displacement, ΔCTOD, is studied in the presence of crack closure to assess the question if ΔJ describes the crack-tip opening displacement in this case. To this end, a method is developed to evaluate ΔJ numerically within finite-element calculations. The method is validated for an elastic-plastic material that exhibits Masing behavior. Different strain ranges and strain ratios are considered under fully plastic cyclic conditions including crack closure. It is shown that the cyclic J-integral is the parameter to determine the cyclic crack-tip opening displacement even in cases where crack closure is present. Kidlington Elsevier Science 2015 14 Engineering Fracture Mechanics 134 459 473 urn:nbn:de:0011-n-3320648 10.1016/j.engfracmech.2014.07.017 Fakultät Maschinenbau und Verfahrenstechnik (M+V)
OPUS4-4280 Buch Nasdala, Lutz FEM-Formelsammlung Statik und Dynamik 2. Wiesbaden Springer Fachmedien 2012 264 978-3-8348-1841-6 (Print) Fakultät Betriebswirtschaft und Wirtschaftsingenieurwesen (B+W)
OPUS4-2062 Buch Nasdala, Lutz FEM-Formelsammlung Statik und Dynamik : Hintergrundinformationen, Tipps und Tricks 3. Wiesbaden Springer Fachmedien 2015 274 978-3-658-06629-1 10.1007/978-3-658-06630-7 Fakultät Betriebswirtschaft und Wirtschaftsingenieurwesen (B+W)
OPUS4-4229 misc Otte, Andreas Götz Prosthesis Reconstructions In this entry, the 3D CAD reconstructions and 3D multi-material polymer replica printings of knight Götz von Berlichingen´s first „Iron Hand," which were developed in the last few years at Offenburg University, are presented. Even by today's standards, the first "Iron Hand"-as could be shown in the replicas-demonstrates sophisticated mechanics and well thought-out functionality and still offers inspiration and food for discussion when it comes to the question of an artificial prosthetic replacement for a hand. 2020 4 Scholarly Community Encyclopedia Fakultät Elektrotechnik, Medizintechnik und Informatik (EMI) (ab 04/2019)
OPUS4-3484 Referierter Artikel Pitzen, Tobias; Geisler, Fred; Matthias, Dieter; Müller-Storz, Hans; Barbier, Dragos; Steudel, Wolf-Ingo A finite element model for predicting the biomechanical behaviour of the human lumbar spine The aim of this study was to develop a biomechanically validated finite element model to predict the biomechanical behaviour of the human lumbar spine in compression. For validation of the finite element model, an in vitro study was performed: Twelve human lumbar cadaveric spinal segments (six segments L2/3 and six segments L4/5) were loaded in axial compression using 600 N in the intact state and following surgical treatment using two different internal stabilisation devices. Range of motion was measured and used to calculate stiffness. A finite element model of a human spinal segment L3/4 was loaded with the same force in intact and surgically altered state, corresponding to the situation of biomechanical in vitro study. The results of the cadaver biomechanical and finite element analysis were compared. As they were close together, the finite element model was used to predict: (1) load-sharing within human lumbar spine in compression, (2) load-sharing within osteoporotic human lumbar spine in compression and (3) the stabilising potential of the different spinal implants with respect to bone mineral density. A finite element model as described here may be used to predict the biomechanical behaviour of the spine. Moreover, the influence of different spinal stabilisation systems may be predicted. Elsevier 2002 7 Control Engineering Practice 10 1 83 90 10.1016/S0967-0661(01)00129-0 Fakultät Maschinenbau und Verfahrenstechnik (M+V)