TY - JOUR A1 - Jiang, Jin-Wu A1 - Wang, Bing-Shen A1 - Rabczuk, Timon T1 - Why twisting angles are diverse in graphene Moir’e patterns? JF - Journal of Applied Physics N2 - Why twisting angles are diverse in graphene Moir’e patterns? KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Döring, R. A1 - Hoffmeyer, J. A1 - Seeger, T. A1 - Vormwald, Michael T1 - Verformungsverhalten und rechnerische Abschätzung der Ermüdungslebensdauer metallischer Werkstoffe unter mehrachsig nichtproportionaler Beanspruchung JF - Materialwissenschaft und Werkstofftechnik N2 - Verformungsverhalten und rechnerische Abschätzung der Ermüdungslebensdauer metallischer Werkstoffe unter mehrachsig nichtproportionaler Beanspruchung KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2002 SP - 280 EP - 288 ER - TY - JOUR A1 - Lahmer, Tom A1 - Ilg, J. A1 - Lerch, Reinhard T1 - Variance-based sensitivity analyses of piezoelectric models JF - Computer Modeling in Engineering & Sciences N2 - Variance-based sensitivity analyses of piezoelectric models KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2015 SP - 105 EP - 126 ER - TY - JOUR A1 - Ilyani Akmar, A.B. A1 - Lahmer, Tom A1 - Bordas, Stéphane Pierre Alain A1 - Beex, L.A.A. A1 - Rabczuk, Timon T1 - Uncertainty quantification of dry woven fabrics: A sensitivity analysis on material properties JF - Composite Structures N2 - Uncertainty quantification of dry woven fabrics: A sensitivity analysis on material properties KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2014 U6 - http://dx.doi.org/10.1016/j.compstruct.2014.04.014 SP - 1 EP - 17 ER - TY - JOUR A1 - Vu-Bac, N. A1 - Rafiee, Roham A1 - Zhuang, Xiaoying A1 - Lahmer, Tom A1 - Rabczuk, Timon T1 - Uncertainty quantification for multiscale modeling of polymer nanocomposites with correlated parameters JF - Composites Part B: Engineering N2 - Uncertainty quantification for multiscale modeling of polymer nanocomposites with correlated parameters KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2015 SP - 446 EP - 464 ER - TY - JOUR A1 - Göbel, Luise A1 - Lahmer, Tom A1 - Osburg, Andrea T1 - Uncertainty analysis in multiscale modeling of concrete based on continuum micromechanics JF - European Journal of Mechanics-A/Solids N2 - Uncertainty analysis in multiscale modeling of concrete based on continuum micromechanics KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2017 ER - TY - JOUR A1 - Ghasemi, Hamid A1 - Rafiee, Roham A1 - Zhuang, Xiaoying A1 - Muthu, Jacob A1 - Rabczuk, Timon T1 - Uncertainties propagation in metamodel-based probabilistic optimization of CNT/polymer composite structure using stochastic multi-scale modeling JF - Computational Materials Science N2 - Uncertainties propagation in metamodel-based probabilistic optimization of CNT/polymer composite structure using stochastic multi-scale modeling KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 SP - 295 EP - 305 ER - TY - JOUR A1 - Nanthakumar, S.S. A1 - Lahmer, Tom A1 - Zhuang, Xiaoying A1 - Park, Harold S. A1 - Rabczuk, Timon T1 - Topology optimization of piezoelectric nanostructures JF - Journal of the Mechanics and Physics of Solids N2 - Topology optimization of piezoelectric nanostructures KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2016 SP - 316 EP - 335 ER - TY - JOUR A1 - Lahmer, Tom A1 - Nguyen-Tuan, Long A1 - Könke, Carsten A1 - Bettzieche, Volker T1 - Thermo-hydro-mechanische 3-D-Simulation von Staumauern‐Modellierung und Validierung JF - WASSERWIRTSCHAFT N2 - Thermo-hydro-mechanische 3-D-Simulation von Staumauern‐Modellierung und Validierung KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2016 SP - 27 EP - 30 ER - TY - JOUR A1 - Zhao, Jiyun A1 - Lu, Lixin A1 - Rabczuk, Timon T1 - The tensile and shear failure behavior dependence on chain length and temperature in amorphous polymers JF - Computational Materials Science N2 - The tensile and shear failure behavior dependence on chain length and temperature in amorphous polymers KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 567 EP - 572 ER - TY - JOUR A1 - Ben, S. A1 - Zhao, Jun-Hua A1 - Zhang, Yancheng A1 - Rabczuk, Timon T1 - The interface strength and debonding for composite structures: review and recent developments JF - Composite Structures N2 - The interface strength and debonding for composite structures: review and recent developments KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 ER - TY - JOUR A1 - Areias, Pedro A1 - Rabczuk, Timon A1 - Barbosa, J.I. T1 - The extended unsymmetric frontal solution for multiple-point constraints JF - Engineering Computations N2 - The extended unsymmetric frontal solution for multiple-point constraints KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 ER - TY - JOUR A1 - Zerbst, U. A1 - Vormwald, Michael A1 - Andersch, C. A1 - Mädler, K. A1 - Pfuff, M. T1 - The development of a damage tolerance concept for railway components and its demonstration for a railway axle JF - Engineering Fracture Mechanics N2 - The development of a damage tolerance concept for railway components and its demonstration for a railway axle KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2005 SP - 209 EP - 239 ER - TY - JOUR A1 - Zhao, Jun-Hua A1 - Kou, Liangzhi A1 - Jiang, Jin-Wu A1 - Rabczuk, Timon T1 - Tension-induced phase transition of single-layer molybdenum disulphide (MoS2) at low temperatures JF - Nanotechnology N2 - Tension-induced phase transition of single-layer molybdenum disulphide (MoS2) at low temperatures KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 U6 - http://dx.doi.org/10.1088/0957-4484/25/29/295701 ER - TY - JOUR A1 - Ghorashi, Seyed Shahram A1 - Valizadeh, Navid A1 - Mohammadi, S. A1 - Rabczuk, Timon T1 - T-spline based XIGA for Fracture Analysis of Orthotropic Media JF - Computers & Structures N2 - T-spline based XIGA for Fracture Analysis of Orthotropic Media KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 138 EP - 146 ER - TY - JOUR A1 - Unger, Jörg F. A1 - Teughels, A. A1 - De Roeck, G. T1 - System identification and damage detection of a prestressed concrete beam JF - Journal of Structural Engineering N2 - System identification and damage detection of a prestressed concrete beam KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2006 SP - 1691 EP - 1698 ER - TY - JOUR A1 - Stein, Peter A1 - Lahmer, Tom A1 - Bock, Sebastian T1 - Synthese und Analyse von gekoppelten Modellen im konstruktiven Ingenieurbau BT - Sonderdruck‐DFG Graduiertenkolleg JF - Bautechnik N2 - Synthese und Analyse von gekoppelten Modellen im konstruktiven Ingenieurbau KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2011 SP - 8 EP - 11 ER - TY - JOUR A1 - Jiang, Jin-Wu A1 - Zhao, Jun-Hua A1 - Zhou, K. A1 - Rabczuk, Timon T1 - Superior thermal conductivity and extremely high mechanical strength in polyethylene chains from ab initio calculation JF - Journal of Applied Physics N2 - The upper limit of the thermal conductivity and the mechanical strength are predicted for the polyethylene chain, by performing the ab initio calculation and applying the quantum mechanical non-equilibrium Green’s function approach. Specially, there are two main findings from our calculation: (1) the thermal conductivity can reach a high value of 310 Wm−1 K−1 in a 100 nm polyethylene chain at room temperature and the thermal conductivity increases with the length of the chain; (2) the Young’s modulus in the polyethylene chain is as high as 374.5 GPa, and the polyethylene chain can sustain 32.85%±0.05% (ultimate) strain before undergoing structural phase transition into gaseous ethylene. KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2012 U6 - http://dx.doi.org/10.1063/1.4729489 ER - TY - JOUR A1 - Most, Thomas A1 - Bucher, Christian T1 - Stochastic simulation of cracking in concrete structures using multi-parameter random fields JF - International Journal of Reliability and Safety N2 - Stochastic simulation of cracking in concrete structures using multi-parameter random fields KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2006 SP - 168 EP - 187 ER - TY - JOUR A1 - Vu-Bac, N. A1 - Lahmer, Tom A1 - Zhang, Yancheng A1 - Zhuang, Xiaoying A1 - Rabczuk, Timon T1 - Stochastic predictions of interfacial characteristic of polymeric nanocomposites (PNCs) JF - Composites Part B Engineering N2 - Stochastic predictions of interfacial characteristic of polymeric nanocomposites (PNCs) KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2014 SP - 80 EP - 95 ER - TY - JOUR A1 - Vu-Bac, N. A1 - Lahmer, Tom A1 - Keitel, Holger A1 - Zhao, Jun-Hua A1 - Zhuang, Xiaoying A1 - Rabczuk, Timon T1 - Stochastic predictions of bulk properties of amorphous polyethylene based on molecular dynamics simulations JF - Mechanics of Materials N2 - Stochastic predictions of bulk properties of amorphous polyethylene based on molecular dynamics simulations KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2014 SP - 70 EP - 84 ER - TY - JOUR A1 - Kerfriden, Pierre A1 - Schmidt, K.M. A1 - Rabczuk, Timon A1 - Bordas, Stéphane Pierre Alain T1 - Statistical extraction of process zones and representative subspaces in fracture of random composites JF - International Journal for Multiscale Computational Engineering N2 - Statistical extraction of process zones and representative subspaces in fracture of random composites KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Thai, Chien H. A1 - Nguyen-Xuan, Hung A1 - Nguyen-Thanh, Nhon A1 - Le, T.H. A1 - Nguyen-Thoi, T. A1 - Rabczuk, Timon T1 - Static, free vibration and buckling analysis of laminated composite Reissner-Mindlin plates using NURBS-based isogeometric approach JF - International Journal for Numerical Methods in Engineering N2 - This paper presents a novel numerical procedure based on the framework of isogeometric analysis for static, free vibration, and buckling analysis of laminated composite plates using the first-order shear deformation theory. The isogeometric approach utilizes non-uniform rational B-splines to implement for the quadratic, cubic, and quartic elements. Shear locking problem still exists in the stiffness formulation, and hence, it can be significantly alleviated by a stabilization technique. Several numerical examples are presented to show the performance of the method, and the results obtained are compared with other available ones. KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2012 U6 - http://dx.doi.org/10.1002/nme.4282 SP - 571 EP - 603 ER - TY - JOUR A1 - Jiang, Jin-Wu A1 - Zhao, Jun-Hua A1 - Rabczuk, Timon T1 - Size-Sensitive Young’s Modulus of Kinked Silicon Nanowires JF - Nanotechnology N2 - We perform both classical molecular dynamics simulations and beam model calculations to investigate the Young's modulus of kinked silicon nanowires (KSiNWs). The Young's modulus is found to be highly sensitive to the arm length of the kink and is essentially inversely proportional to the arm length. The mechanism underlying the size dependence is found to be the interplay between the kink angle potential and the arm length potential, where we obtain an analytic relationship between the Young's modulus and the arm length of the KSiNW. Our results provide insight into the application of this novel building block in nanomechanical devices. KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 U6 - http://dx.doi.org/10.1088/0957-4484/24/18/185702 ER - TY - JOUR A1 - Natarajan, S. A1 - Chakraborty, S. A1 - Thangavel, M. A1 - Bordas, Stéphane Pierre Alain A1 - Rabczuk, Timon T1 - Size dependent free flexural vibration behavior of functionally graded nanoplates JF - Computational Materials Science N2 - Size dependent free flexural vibration behavior of functionally graded nanoplates KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2012 SP - 74 EP - 80 ER - TY - JOUR A1 - Ghasemi, Hamid A1 - Brighenti, Roberto A1 - Zhuang, Xiaoying A1 - Muthu, Jacob A1 - Rabczuk, Timon T1 - Sequential reliability based optimization of fiber content and dispersion in fiber reinforced composite by using NURBS finite elements JF - Structural and Multidisciplinary Optimization N2 - Sequential reliability based optimization of fiber content and dispersion in fiber reinforced composite by using NURBS finite elements KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 ER - TY - JOUR A1 - Nasser, Mourad A1 - Schwedler, Michael A1 - Wuttke, Frank A1 - Könke, Carsten T1 - Seismic analysis of structural response using simplified soil-structure interaction models JF - Bauingenieur, D-A-CH-Mitteilungsblatt N2 - Seismic analysis of structural response using simplified soil-structure interaction models KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2010 ER - TY - JOUR A1 - Nguyen-Thanh, Nhon A1 - Kiendl, J. A1 - Nguyen-Xuan, Hung A1 - Wüchner, R. A1 - Bletzinger, Kai-Uwe A1 - Bazilevs, Yuri A1 - Rabczuk, Timon T1 - Rotation free isogeometric thin shell analysis using PHT-splines JF - Computer Methods in Applied Mechanics and Engineering N2 - Rotation free isogeometric thin shell analysis using PHT-splines KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2011 SP - 3410 EP - 3424 ER - TY - JOUR A1 - Thumser, Rayk A1 - Bergmann, Joachim W. A1 - Vormwald, Michael T1 - Residual stress fields and fatigue analysis of autofrettaged parts JF - International Journal of Pressure Vessels and Piping N2 - Residual stress fields and fatigue analysis of autofrettaged parts KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2002 SP - 113 EP - 117 ER - TY - JOUR A1 - Beex, L.A.A. A1 - Kerfriden, Pierre A1 - Rabczuk, Timon A1 - Bordas, Stéphane Pierre Alain T1 - Quasicontinuum-based multiscale approaches for plate-like beam lattices experiencing in-plane and out-of-plane deformation JF - Computer Methods in Applied Mechanics and Engineering N2 - Quasicontinuum-based multiscale approaches for plate-like beam lattices experiencing in-plane and out-of-plane deformation KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 ER - TY - JOUR A1 - Zhang, Yancheng A1 - Wei, Ning A1 - Zhao, Jun-Hua A1 - Gong, Yadong A1 - Rabczuk, Timon T1 - Quasi-analytical solution for the stable system of the multi-layer folded graphene wrinkles JF - Journal of Applied Physics N2 - Quasi-analytical solution for the stable system of the multi-layer folded graphene wrinkles KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Most, Thomas A1 - Bucher, Christian T1 - Probabilistic analysis of concrete cracking using neural networks and random fields JF - Probabilistic Engineering Mechanics N2 - Probabilistic analysis of concrete cracking using neural networks and random fields KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2007 SP - 219 EP - 229 ER - TY - JOUR A1 - Hamdia, Khader A1 - Lahmer, Tom A1 - Nguyen-Thoi, T. A1 - Rabczuk, Timon T1 - Predicting The Fracture Toughness of PNCs: A Stochastic Approach Based on ANN and ANFIS JF - Computational Materials Science N2 - Predicting The Fracture Toughness of PNCs: A Stochastic Approach Based on ANN and ANFIS KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2015 SP - 304 EP - 313 ER - TY - JOUR A1 - Luther, Torsten A1 - Könke, Carsten T1 - Polycrystal models for the analysis of intergranular crack growth in metallic materials JF - Engineering Fracture Mechanics N2 - Polycrystal models for the analysis of intergranular crack growth in metallic materials KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2009 SP - 2332 EP - 2343 ER - TY - JOUR A1 - Jiang, Jin-Wu A1 - Wang, Bing-Shen A1 - Rabczuk, Timon T1 - Phonon modes in single-walled molybdenum disulphide nanotubes: lattice dynamics calculation and molecular dynamics simulation JF - Nanotechnology N2 - Phonon modes in single-walled molybdenum disulphide nanotubes: lattice dynamics calculation and molecular dynamics simulation KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 ER - TY - JOUR A1 - Amiri, Fatemeh A1 - Millán, D. A1 - Shen, Y. A1 - Rabczuk, Timon A1 - Arroyo, M. T1 - Phase-field modeling of fracture in linear thin shells JF - Theoretical and Applied Fracture Mechanics N2 - Phase-field modeling of fracture in linear thin shells KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 SP - 102 EP - 109 ER - TY - JOUR A1 - Jamshidian, M. A1 - Rabczuk, Timon T1 - Phase field modelling of stressed grain growth: Analytical study and the effect of microstructural length scale JF - Journal of Computational Physics N2 - Phase field modelling of stressed grain growth: Analytical study and the effect of microstructural length scale KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 SP - 23 EP - 35 ER - TY - JOUR A1 - Chau-Dinh, T. A1 - Zi, Goangseup A1 - Lee, P.S. A1 - Song, Jeong-Hoon A1 - Rabczuk, Timon T1 - Phantom-node method for shell models with arbitrary cracks JF - Computers & Structures N2 - A phantom-node method is developed for three-node shell elements to describe cracks. This method can treat arbitrary cracks independently of the mesh. The crack may cut elements completely or partially. Elements are overlapped on the position of the crack, and they are partially integrated to implement the discontinuous displacement across the crack. To consider the element containing a crack tip, a new kinematical relation between the overlapped elements is developed. There is no enrichment function for the discontinuous displacement field. Several numerical examples are presented to illustrate the proposed method. KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.compstruc.2011.10.021 ER - TY - JOUR A1 - Kaltenbacher, Barbara A1 - Lahmer, Tom A1 - Mohr, Marcus A1 - Kaltenbacher, Manfred T1 - PDE based determination of piezoelectric material tensors JF - European Journal of Applied Mathematics N2 - PDE based determination of piezoelectric material tensors. KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2006 U6 - http://dx.doi.org/10.25643/bauhaus-universitaet.3595 SP - 383 EP - 416 ER - TY - JOUR A1 - Ghasemi, Hamid A1 - Brighenti, Roberto A1 - Zhuang, Xiaoying A1 - Muthu, Jacob A1 - Rabczuk, Timon T1 - Optimum fiber content and distribution in fiber-reinforced solids using a reliability and NURBS based sequential optimization approach JF - Structural and Multidisciplinary Optimization N2 - Optimum _ber content and distribution in _ber-reinforced solids using a reliability and NURBS based sequential optimization approach KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 99 EP - 112 ER - TY - JOUR A1 - Macke, M. A1 - Higuchi, Shoko T1 - Optimizing maintenance interventions for deteriorating structures using cost-benefit criteria JF - Journal of Structural Engineering N2 - Optimizing maintenance interventions for deteriorating structures using cost-benefit criteria KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2007 SP - 925 EP - 934 ER - TY - JOUR A1 - Bucher, Christian A1 - Frangopol, D.M. T1 - Optimization of lifetime maintenance strategies for deteriorting structures considering probabilities of violating safety, condition, and cost thresholds JF - Probabilistic Engineering Mechanics N2 - Optimization of lifetime maintenance strategies for deteriorting structures considering probabilities of violating safety, condition, and cost thresholds KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2006 SP - 1 EP - 8 ER - TY - JOUR A1 - Ghasemi, Hamid A1 - Brighenti, Roberto A1 - Zhuang, Xiaoying A1 - Muthu, Jacob A1 - Rabczuk, Timon T1 - Optimization of fiber distribution in fiber reinforced composite by using NURBS functions JF - Computational Materials Science N2 - Optimization of fiber distribution in fiber reinforced composite by using NURBS functions KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 SP - 463 EP - 473 ER - TY - JOUR A1 - Bakar, I. A1 - Kramer, O. A1 - Bordas, Stéphane Pierre Alain A1 - Rabczuk, Timon T1 - Optimization of Elastic Properties and Weaving Patterns of Woven Composites JF - Composite Structures N2 - Optimization of Elastic Properties and Weaving Patterns of Woven Composites KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 SP - 575 EP - 591 ER - TY - THES A1 - Schemmann, Christoph T1 - Optimierung von radialen Verdichterlaufrädern unter Berücksichtigung empirischer und analytischer Vorinformationen mittels eines mehrstufigen Sampling Verfahrens T1 - Optimization of Centrifugal Compressor Impellers by a Multi-fidelity Sampling Method Taking Analytical and Empirical Information into Account N2 - Turbomachinery plays an important role in many cases of energy generation or conversion. Therefore, turbomachinery is a promising approaching point for optimization in order to increase the efficiency of energy use. In recent years, the use of automated optimization strategies in combination with numerical simulation has become increasingly popular in many fields of engineering. The complex interactions between fluid and solid mechanics encountered in turbomachines on the one hand and the high computational expense needed to calculate the performance on the other hand, have, however, prevented a widespread use of these techniques in this field of engineering. The objective of this work was the development of a strategy for efficient metamodel based optimization of centrifugal compressor impellers. In this context, the main focus is the reduction of the required numerical expense. The central idea followed in this research was the incorporation of preliminary information acquired from low-fidelity computation methods and empirical correlations into the sampling process to identify promising regions of the parameter space. This information was then used to concentrate the numerically expensive high-fidelity computations of the fluid dynamic and structure mechanic performance of the impeller in these regions while still maintaining a good coverage of the whole parameter space. The development of the optimization strategy can be divided into three main tasks. Firstly, the available preliminary information had to be researched and rated. This research identified loss models based on one dimensional flow physics and empirical correlations as the best suited method to predict the aerodynamic performance. The loss models were calibrated using available performance data to obtain a high prediction quality. As no sufficiently exact models for the prediction of the mechanical loading of the impellercould be identified, a metamodel based on finite element computations was chosen for this estimation. The second task was the development of a sampling method which concentrates samples in regions of the parameter space where high quality designs are predicted by the preliminary information while maintaining a good overall coverage. As available methods like rejection sampling or Markov-chain Monte-Carlo methods did not meet the requirements in terms of sample distribution and input correlation, a new multi-fidelity sampling method called “Filtered Sampling“has been developed. The last task was the development of an automated computational workflow. This workflow encompasses geometry parametrization, geometry generation, grid generation and computation of the aerodynamic performance and the structure mechanic loading. Special emphasis was put into the development of a geometry parametrization strategy based on fluid mechanic considerations to prevent the generation of physically inexpedient designs. Finally, the optimization strategy, which utilizes the previously developed tools, was successfully employed to carry out three optimization tasks. The efficiency of the method was proven by the first and second testcase where an existing compressor design was optimized by the presented method. The results were comparable to optimizations which did not take preliminary information into account, while the required computational expense cloud be halved. In the third testcase, the method was applied to generate a new impeller design. In contrast to the previous examples, this optimization featuredlargervariationsoftheimpellerdesigns. Therefore, theapplicability of the method to parameter spaces with significantly varying designs could be proven, too. N2 - Turbomaschinen sind eine entscheidende Komponente in vielen Energiewandlungs- oder Energieerzeugungsprozessen und daher als vielversprechender Ansatzpunkt für eine Effizienzsteigerung der Energie-und Ressourcennutzung anzusehen. Im Laufe des letzten Jahrzehnts haben automatisierte Optimierungsmethoden in Verbindung mit numerischer Simulation zunehmend breitere Verwendung als Mittel zur Effizienzsteigerung in vielen Bereichen der Ingenieurwissenschaften gefunden. Allerdings standen die komplexen Interaktionen zwischen Strömungs- und Strukturmechanik sowie der hohe nummerische Aufwand einem weitverbreiteten Einsatz dieser Methoden im Turbomaschinenbereich bisher entgegen. Das Ziel dieser Forschungsaktivität ist die Entwicklung einer effizienten Strategie zur metamodellbasierten Optimierung von radialen Verdichterlaufrädern. Dabei liegt der Schwerpunkt auf einer Reduktion des benötigten numerischen Aufwandes. Der in diesem Vorhaben gewählte Ansatz ist das Einbeziehen analytischer und empirischer Vorinformationen (“lowfidelity“) in den Sampling Prozess, um vielversprechende Bereiche des Parameterraumes zu identifizieren. Diese Informationen werden genutzt um die aufwendigen numerischen Berechnungen (“high-fidelity“) des strömungs- und strukturmechanischen Verhaltens der Laufräder in diesen Bereichen zu konzentrieren, während gleichzeitig eine ausreichende Abdeckung des gesamten Parameterraumes sichergestellt wird. Die Entwicklung der Optimierungsstrategie ist in drei zentrale Arbeitspakete aufgeteilt. In einem ersten Schritt werden die verfügbaren empirischen und analytischen Methoden gesichtet und bewertet. In dieser Recherche sind Verlustmodelle basierend auf eindimensionaler Strömungsmechanik und empirischen Korrelationen als bestgeeignete Methode zur Vorhersage des aerodynamischen Verhaltens der Verdichter identifiziert worden. Um eine hohe Vorhersagegüte sicherzustellen, sind diese Modelle anhand verfügbarer Leistungsdaten kalibriert worden. Da zur Vorhersage der mechanischen Belastung des Laufrades keine brauchbaren analytischen oder empirischen Modelle ermittelt werden konnten, ist hier ein Metamodel basierend auf Finite-Element Berechnungen gewählt worden. Das zweite Arbeitspaket beinhaltet die Entwicklung der angepassten Samplingmethode, welche Samples in Bereichen des Parameterraumes konzentriert, die auf Basis der Vorinformationen als vielversrechend angesehen werden können. Gleichzeitig müssen eine gleichmäßige Abdeckung des gesamten Parameterraumes und ein niedriges Niveau an Eingangskorrelationen sichergestellt sein. Da etablierte Methoden wie Markov-Ketten-Monte-Carlo-Methoden oder die Verwerfungsmethode diese Voraussetzungen nicht erfüllen, ist ein neues, mehrstufiges Samplingverfahren (“Filtered Sampling“) entwickelt worden. Das letzte Arbeitspaket umfasst die Entwicklung eines automatisiertenSimulations-Workflows. Dieser Workflow umfasst Geometrieparametrisierung, Geometrieerzeugung, Netzerzeugung sowie die Berechnung des aerodynamischen Betriebsverhaltens und der strukturmechanischen Belastung. Dabei liegt ein Schwerpunkt auf der Entwicklung eines Parametrisierungskonzeptes, welches auf strömungsmechanischen Zusammenhängen beruht, um so physikalisch nicht zielführende Parameterkombinationen zu vermeiden. Abschließend ist die auf den zuvor entwickelten Werkzeugen aufbauende Optimierungsstrategie erfolgreich eingesetzt worden, um drei Optimierungsfragestellungen zu bearbeiten. Im ersten und zweiten Testcase sind bestehende Verdichterlaufräder mit der vorgestellten Methode optimiert worden. Die erzielten Optimierungsergebnisse sind von ähnlicher Güte wie die solcher Optimierungen, die keine Vorinformationen berücksichtigen, allerdingswirdnurdieHälfteannumerischemAufwandbenötigt. IneinemdrittenTestcase ist die Methode eingesetzt worden, um ein neues Laufraddesign zu erzeugen. Im Gegensatz zu den vorherigen Beispielen werden im Rahmen dieser Optimierung stark unterschiedliche Designs untersucht. Dadurch kann an diesem dritten Beispiel aufgezeigt werden, dass die Methode auch für Parameterräume mit stakt variierenden Designs funktioniert. T3 - ISM-Bericht // Institut für Strukturmechanik, Bauhaus-Universität Weimar - 2019,3 KW - Simulation KW - Maschinenbau KW - Optimierung KW - Strömungsmechanik KW - Strukturmechanik Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20190910-39748 ER - TY - JOUR A1 - Lahmer, Tom A1 - Könke, Carsten A1 - Bettzieche, Volker T1 - Optimale Positionierung von Messeinrichtungen an Staumauern zur Bauwerksüberwachung JF - WASSERWIRTSCHAFT N2 - Optimale Positionierung von Messeinrichtungen an Staumauern zur Bauwerksüberwachung KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2010 SP - 16 EP - 16 ER - TY - JOUR A1 - Brehm, Maik A1 - Zabel, Volkmar A1 - Bucher, Christian T1 - Optimal reference sensor positions for applications in model updating using output-only vibration test data based on random excitation: Part 2 - improved search strategy and experimental case study JF - Mechanical Systems and Signal Processing N2 - Optimal reference sensor positions for applications in model updating using output-only vibration test data based on random excitation: Part 2 - improved search strategy and experimental case study KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2011 ER - TY - JOUR A1 - Lahmer, Tom A1 - Könke, Carsten A1 - Bettzieche, Volker T1 - Optimal positioning of sensors for the monitoring of water dams JF - WASSERWIRTSCHAFT N2 - Optimal positioning of sensors for the monitoring of water dams KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2010 SP - 16 EP - 19 ER - TY - JOUR A1 - Lahmer, Tom A1 - Kaltenbacher, Barbara A1 - Schulz, V. T1 - Optimal measurement selection for piezoelectric material tensor identification JF - Inverse Problems in Science and Engineering N2 - Optimal measurement selection for piezoelectric material tensor identification. KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2008 U6 - http://dx.doi.org/10.25643/bauhaus-universitaet.3593 SP - 369 EP - 387 ER - TY - JOUR A1 - Lahmer, Tom T1 - Optimal experimental design for nonlinear ill-posed problems applied to gravity dams JF - Inverse Problems N2 - Optimal experimental design for nonlinear ill-posed problems applied to gravity dams KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2011 ER - TY - JOUR A1 - Talebi, Hossein A1 - Samaniego, C. A1 - Samaniego, Esteban A1 - Rabczuk, Timon T1 - On the numerical stability and mass-lumping schemes for explicit enriched meshfree methods JF - International Journal for Numerical Methods in Engineering N2 - Meshfree methods (MMs) such as the element free Galerkin (EFG)method have gained popularity because of some advantages over other numerical methods such as the finite element method (FEM). A group of problems that have attracted a great deal of attention from the EFG method community includes the treatment of large deformations and dealing with strong discontinuities such as cracks. One efficient solution to model cracks is adding special enrichment functions to the standard shape functions such as extended FEM, within the FEM context, and the cracking particles method, based on EFG method. It is well known that explicit time integration in dynamic applications is conditionally stable. Furthermore, in enriched methods, the critical time step may tend to very small values leading to computationally expensive simulations. In this work, we study the stability of enriched MMs and propose two mass-lumping strategies. Then we show that the critical time step for enriched MMs based on lumped mass matrices is of the same order as the critical time step of MMs without enrichment. Moreover, we show that, in contrast to extended FEM, even with a consistent mass matrix, the critical time step does not vanish even when the crack directly crosses a node. KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2012 U6 - http://dx.doi.org/10.1002/nme.3275 SP - 1009 EP - 1027 ER - TY - JOUR A1 - Silani, Mohammad A1 - Talebi, Hossein A1 - Arnold, Daniel A1 - Ziaei-Rad, S. A1 - Rabczuk, Timon T1 - On the coupling of a commercial finite element package with lammps for multiscale modeling of materials JF - Steel Research International N2 - On the coupling of a commercial finite element package with lammps for multiscale modeling of materials KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Bucher, Christian A1 - Pham, Hoang Anh T1 - On model updating of existing structures utilizing measured dynamic responses JF - Structure and Infrastructure Engineering N2 - On model updating of existing structures utilizing measured dynamic responses KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2005 SP - 135 EP - 143 ER - TY - JOUR A1 - Valizadeh, Navid A1 - Natarajan, S. A1 - Gonzalez-Estrada, O.A. A1 - Rabczuk, Timon A1 - Tinh Quoc, Bui A1 - Bordas, Stéphane Pierre Alain T1 - NURBS-based finite element analysis of functionally graded plates: static bending, vibration, buckling and flutter JF - Composite Structures N2 - NURBS-based finite element analysis of functionally graded plates: static bending, vibration, buckling and flutter KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 SP - 309 EP - 326 ER - TY - JOUR A1 - Bruhin, R. A1 - Stock, U.A. A1 - Drücker, J.-P. A1 - Azhari, T. A1 - Wippermann, J. A1 - Albes, J.M. A1 - Hintze, D. A1 - Eckardt, Stefan A1 - Könke, Carsten A1 - Wahlers, T. T1 - Numerical simulation techniques to study the structural response of the human chest following median sternotomy JF - The Annals of Thoracic Surgery N2 - Numerical simulation techniques to study the structural response of the human chest following median sternotomy KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2005 SP - 623 EP - 630 ER - TY - THES A1 - Itam, Zarina T1 - Numerical Simulation of Thermo-Chemo-Hygro-Mechanical Alkali-Silica Reaction Model in Concrete at the Mesoscale and Macroscale N2 - Alkali-silica reaction causes major problems in concrete structures due to the rapidity of its deformation which leads to the serviceability limit of the structure being reached well before its time. Factors that affect ASR vary greatly, including alkali and silica content, relative humidity, temperature and porosity of the cementitious matrix,all these making it a very complex phenomenon to consider explicitly. With this in mind, the finite element technique was used to build models and generate expansive pressures and damage propagation due to ASR under the influence of thermo-hygrochemoelastic loading. Since ASR initializes in the mesoscopic regions of the concrete, the accumulative effects of its expansion escalates onto the macroscale level with the development of web cracking on the concrete surface, hence solution of the damage model as well as simulation of the ASR phenomenon at both the macroscale and mesoscale levels have been performed. The macroscale model realizes the effects of ASR expansion as a whole and shows how it develops under the influence of moisture, thermal and mechanical loading. Results of the macroscale modeling are smeared throughout the structure and are sufficient to show how damage due to ASR expansion orientates. As opposed to the mesoscale model, the heterogeneity of the model shows us how difference in material properties between aggregates and the cementitious matrix facilitates ASR expansion. With both these models, the ASR phenomenon under influence of thermo-chemo-hygro-mechanical loading can be better understood. T3 - ISM-Bericht // Institut für Strukturmechanik, Bauhaus-Universität Weimar - 2014,2 KW - Strukturmechanik KW - Alkali-silica reaction KW - macroscale KW - mesoscale KW - ASR Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20141218-23352 ER - TY - JOUR A1 - Kirichuk, A. A1 - Most, Thomas A1 - Bucher, Christian T1 - Numerical nonlinear analysis of kinematically excited shells JF - International Journal for Computational Civil and Structural Engineering N2 - Numerical nonlinear analysis of kinematically excited shells KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2003 SP - 61 EP - 74 ER - TY - JOUR A1 - Nguyen-Tuan, Long A1 - Könke, Carsten A1 - Bettzieche, Volker A1 - Lahmer, Tom T1 - Numerical modeling and validation for 3D coupled-nonlinear thermo-hydro-mechanical problems in masonry dams JF - Computers & Structures N2 - Numerical modeling and validation for 3D coupled-nonlinear thermo-hydro-mechanical problems in masonry dams KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2017 SP - 143 EP - 154 ER - TY - JOUR A1 - Lahmer, Tom A1 - Bock, Sebastian A1 - Hildebrand, Jörg A1 - Gürlebeck, Klaus T1 - Non-destructive identification of residual stresses in steel under thermal loadings JF - Inverse Problems in Science and Engineering N2 - Non-destructive identification of residual stresses in steel under thermal loadings KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2016 SP - 1 EP - 17 ER - TY - JOUR A1 - Bucher, Christian A1 - Ebert, Matthias T1 - Nichtlineare Berechnung von Stahlflanschverbindungen mit gemessenen Imperfektionen JF - Stahlbau N2 - Nichtlineare Berechnung von Stahlflanschverbindungen mit gemessenen Imperfektionen KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2002 SP - 516 EP - 522 ER - TY - JOUR A1 - Most, Thomas A1 - Bucher, Christian T1 - New concepts for moving least squares: An interpolating non-singular weighting function and weighted nodal least squares JF - Engineering Analysis with Boundary Elements N2 - New concepts for moving least squares: An interpolating non-singular weighting function and weighted nodal least squares KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2008 SP - 461 EP - 470 ER - TY - JOUR A1 - Arash, Behrouz A1 - Rabczuk, Timon A1 - Jiang, Jin-Wu T1 - Nanoresonators and their applications: a state of the art review JF - Applied Physics Reviews N2 - Nanoresonators and their applications: a state of the art review KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 ER - TY - JOUR A1 - Könke, Carsten A1 - Eckardt, Stefan A1 - Häfner, Stefan A1 - Luther, Torsten A1 - Unger, Jörg F. T1 - Multiscale simulation methods in damage prediction of brittle and ductile materials JF - International Journal for Multiscale Computational Engineering N2 - Multiscale simulation methods in damage prediction of brittle and ductile materials KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2010 SP - 17 EP - 36 ER - TY - JOUR A1 - Mortazavi, Bohayra A1 - Rabczuk, Timon T1 - Multiscale modeling of heat conduction in graphene laminates JF - Carbon N2 - Multiscale modeling of heat conduction in graphene laminates KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 1 EP - 7 ER - TY - JOUR A1 - Zhang, Chao A1 - Nanthakumar, S.S. A1 - Lahmer, Tom A1 - Rabczuk, Timon T1 - Multiple cracks identification for piezoelectric structures JF - International Journal of Fracture N2 - Multiple cracks identification for piezoelectric structures KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2017 SP - 1 EP - 19 ER - TY - JOUR A1 - Jiang, Jin-Wu A1 - Park, Harold S. A1 - Rabczuk, Timon T1 - MoS2 nanoresonators: intrinsically better than graphene? JF - Nanoscale N2 - MoS2 nanoresonators: intrinsically better than graphene? KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 SP - 3618 EP - 3625 ER - TY - JOUR A1 - Talebi, Hossein A1 - Silani, Mohammad A1 - Bordas, Stéphane Pierre Alain A1 - Kerfriden, Pierre A1 - Rabczuk, Timon T1 - Molecular Dynamics/XFEM Coupling by a Three-Dimensional Extended Bridging Domain with Applications to Dynamic Brittle Fracture JF - International Journal for Multiscale Computational Engineering N2 - Molecular Dynamics/XFEM Coupling by a Three-Dimensional Extended Bridging Domain with Applications to Dynamic Brittle Fracture KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Jiang, Jin-Wu A1 - Rabczuk, Timon T1 - Modulation of Thermal Conductivity in kinked Silicon Nanowires: Phonon interchanging and pinching effects or Reduction of thermal conductivity in kinked silicon nanowire superlattices JF - Nano Letters N2 - Modulation of Thermal Conductivity in kinked Silicon Nanowires: Phonon interchanging and pinching effects or Reduction of thermal conductivity in kinked silicon nanowire superlattices KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Lahmer, Tom T1 - Modified Landweber iterations in a multilevel algorithm applied to inverse problems in piezoelectricity JF - Journal of Inverse and Ill-posed Problems N2 - Modified Landweber iterations in a multilevel algorithm applied to inverse problems in piezoelectricity KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2009 SP - 585 EP - 593 ER - TY - JOUR A1 - Unger, Jörg F. A1 - Eckardt, Stefan A1 - Könke, Carsten T1 - Modelling of cohesive crack growth in concrete structures with the extended finite element method JF - Computer Methods in Applied Mechanics and Engineering N2 - Modelling of cohesive crack growth in concrete structures with the extended finite element method KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2007 SP - 4087 EP - 4100 ER - TY - JOUR A1 - Kumar, S. A1 - Singh, I. A1 - Mishra, B.K. A1 - Rabczuk, Timon T1 - Modeling and Simulation of Kinked Cracks by Virtual Node XFEM JF - Computer Methods in Applied Mechanics and Engineering N2 - Modeling and Simulation of Kinked Cracks by Virtual Node XFEM KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 1425 EP - 1466 ER - TY - JOUR A1 - Häfner, Stefan A1 - Eckardt, Stefan A1 - Luther, Torsten A1 - Könke, Carsten T1 - Mesoscale modeling of concrete: Geometry and numerics JF - Computers and Structures N2 - Mesoscale modeling of concrete: Geometry and numerics KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2006 SP - 450 EP - 461 ER - TY - JOUR A1 - Zhao, Jun-Hua A1 - Wei, Ning A1 - Fan, Z. A1 - Jiang, Jin-Wu A1 - Rabczuk, Timon T1 - Mechanical properties of three types of carbon allotropes JF - Nanotechnology N2 - Mechanical properties of three types of carbon allotropes KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Mortazavi, Bohayra A1 - Cuniberti, G. A1 - Rabczuk, Timon T1 - Mechanical properties and thermal conductivity of graphitic carbon nitride: A molecular dynamics study JF - Computational Materials Science N2 - Mechanical properties and thermal conductivity of graphitic carbon nitride: A molecular dynamics study KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 285 EP - 289 ER - TY - JOUR A1 - Jiang, Jin-Wu A1 - Rabczuk, Timon T1 - Mechanical Oscillation of Kinked Silicon Nanowires: a Natural Nanoscale Spring JF - Applied Physics Letters N2 - Mechanical Oscillation of Kinked Silicon Nanowires: a Natural Nanoscale Spring KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Zhang, Yancheng A1 - Zhuang, Xiaoying A1 - Muthu, Jacob A1 - Mabrouki, Tarek A1 - Fontaine, Michaël A1 - Gong, Yadong A1 - Rabczuk, Timon T1 - Load transfer of graphene/carbon nanotube/polyethylene hybrid nanocomposite by molecular dynamics simulation JF - Composites Part B Engineering N2 - Load transfer of graphene/carbon nanotube/polyethylene hybrid nanocomposite by molecular dynamics simulation KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 SP - 27 EP - 33 ER - TY - JOUR A1 - Savaidis, G. A1 - Schliebner, R. A1 - Vormwald, Michael T1 - Lebensdauerermittlung von geschweißten, mehrachsig belasteten Nutzfahrzeugkomponenten - Vergleich von Schwingfestigkeiten aus Rechnung und Versuch bei nichtproportionaler Beanspruchung JF - Materialprüfung N2 - Lebensdauerermittlung von geschweißten, mehrachsig belasteten Nutzfahrzeugkomponenten - Vergleich von Schwingfestigkeiten aus Rechnung und Versuch bei nichtproportionaler Beanspruchung KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2001 SP - 381 EP - 386 ER - TY - JOUR A1 - Hoffmeyer, J. A1 - Döring, R. A1 - Vormwald, Michael T1 - Kurzrisswachstum bei mehrachsig nichtproportionaler Beanspruchung JF - Materialwissenschaft und Werkstofftechnik N2 - Kurzrisswachstum bei mehrachsig nichtproportionaler Beanspruchung KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2001 SP - 329 EP - 336 ER - TY - JOUR A1 - Nguyen-Thanh, Nhon A1 - Nguyen-Xuan, Hung A1 - Bordas, Stéphane Pierre Alain A1 - Rabczuk, Timon T1 - Isogeometric analysis using polynomial splines over hierarchical T-meshes for two-dimensional elastic solids JF - Computer Methods in Applied Mechanics and Engineering N2 - Isogeometric analysis using polynomial splines over hierarchical T-meshes for two-dimensional elastic solids KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2011 SP - 1892 EP - 1908 ER - TY - JOUR A1 - Nguyen, V.P. A1 - Kerfriden, Pierre A1 - Bordas, Stéphane Pierre Alain A1 - Rabczuk, Timon T1 - Isogeometric analysis suitable trivariate NURBS representation of composite panels with a new offset algorithm JF - Computer-Aided Design N2 - Isogeometric analysis suitable trivariate NURBS representation of composite panels with a new offset algorithm KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 ER - TY - JOUR A1 - Thai, Chien H. A1 - Nguyen-Xuan, Hung A1 - Bordas, Stéphane Pierre Alain A1 - Nguyen-Thanh, Nhon A1 - Rabczuk, Timon T1 - Isogeometric analysis of laminated composite plates using the higher-order shear deformation theory JF - Mechanics of Advanced Materials and Structures N2 - Isogeometric analysis of laminated composite plates using the higher-order shear deformation theory KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 451 EP - 469 ER - TY - JOUR A1 - Thai, Chien H. A1 - Ferreira, A.J.M. A1 - Bordas, Stéphane Pierre Alain A1 - Rabczuk, Timon A1 - Nguyen-Xuan, Hung T1 - Isogeometric analysis of laminated composite and sandwich plates using a new inverse trigonometric shear deformation theory JF - European Journal of Mechanics N2 - Isogeometric analysis of laminated composite and sandwich plates using a new inverse trigonometric shear deformation theory KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 SP - 89 EP - 108 ER - TY - JOUR A1 - Ghasemi, Hamid A1 - Kerfriden, Pierre A1 - Bordas, Stéphane Pierre Alain A1 - Muthu, Jacob A1 - Zi, Goangseup A1 - Rabczuk, Timon T1 - Interfacial shear stress optimization in sandwich beams with polymeric core using nonuniform distribution of reinforcing ingredients JF - Composite Structures N2 - Interfacial shear stress optimization in sandwich beams with polymeric core using nonuniform distribution of reinforcing ingredients KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 221 EP - 230 ER - TY - JOUR A1 - Areias, Pedro A1 - Rabczuk, Timon A1 - Dias-da-Costa, D. A1 - Piresh, E.B. T1 - Implicit solutions with consistent additive and multiplicative components JF - Finite Elements in Analysis and Design N2 - This work describes an algorithm and corresponding software for incorporating general nonlinear multiple-point equality constraints in a implicit sparse direct solver. It is shown that direct addressing of sparse matrices is possible in general circumstances, circumventing the traditional linear or binary search for introducing (generalized) constituents to a sparse matrix. Nested and arbitrarily interconnected multiple-point constraints are introduced by processing of multiplicative constituents with a built-in topological ordering of the resulting directed graph. A classification of discretization methods is performed and some re-classified problems are described and solved under this proposed perspective. The dependence relations between solution methods, algorithms and constituents becomes apparent. Fracture algorithms can be naturally casted in this framework. Solutions based on control equations are also directly incorporated as equality constraints. We show that arbitrary constituents can be used as long as the resulting directed graph is acyclic. It is also shown that graph partitions and orderings should be performed in the innermost part of the algorithm, a fact with some peculiar consequences. The core of our implicit code is described, specifically new algorithms for direct access of sparse matrices (by means of the clique structure) and general constituent processing. It is demonstrated that the graph structure of the second derivatives of the equality constraints are cliques (or pseudo-elements) and are naturally included as such. A complete algorithm is presented which allows a complete automation of equality constraints, avoiding the need of pre-sorting. Verification applications in four distinct areas are shown: single and multiple rigid body dynamics, solution control and computational fracture. KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.finel.2012.03.007 SP - 15 EP - 31 ER - TY - JOUR A1 - Zhang, Yongzheng A1 - Ren, Huilong T1 - Implicit implementation of the nonlocal operator method: an open source code JF - Engineering with computers N2 - In this paper, we present an open-source code for the first-order and higher-order nonlocal operator method (NOM) including a detailed description of the implementation. The NOM is based on so-called support, dual-support, nonlocal operators, and an operate energy functional ensuring stability. The nonlocal operator is a generalization of the conventional differential operators. Combined with the method of weighed residuals and variational principles, NOM establishes the residual and tangent stiffness matrix of operate energy functional through some simple matrix without the need of shape functions as in other classical computational methods such as FEM. NOM only requires the definition of the energy drastically simplifying its implementation. The implementation in this paper is focused on linear elastic solids for sake of conciseness through the NOM can handle more complex nonlinear problems. The NOM can be very flexible and efficient to solve partial differential equations (PDEs), it’s also quite easy for readers to use the NOM and extend it to solve other complicated physical phenomena described by one or a set of PDEs. Finally, we present some classical benchmark problems including the classical cantilever beam and plate-with-a-hole problem, and we also make an extension of this method to solve complicated problems including phase-field fracture modeling and gradient elasticity material. KW - Strukturmechanik KW - Nonlocal operator method KW - Operator energy functional KW - Implicit KW - Dual-support KW - Variational principle KW - Taylor series expansion KW - Stiffness matrix Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20220216-45930 UR - https://link.springer.com/article/10.1007/s00366-021-01537-x VL - 2022 SP - 1 EP - 35 PB - Springer CY - London ER - TY - JOUR A1 - Knabe, Tina A1 - Datcheva, Maria A1 - Lahmer, Tom A1 - Cotecchia, F. A1 - Schanz, Tom T1 - Identification of constitutive parameters of soil using an optimization strategy and statistical analysis JF - Computers and Geotechnics N2 - Identification of constitutive parameters of soil using an optimization strategy and statistical analysis KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2013 SP - 143 EP - 157 ER - TY - JOUR A1 - Luu, M. A1 - Martinez-Rodrigo, M.D. A1 - Zabel, Volkmar A1 - Könke, Carsten T1 - H∞ optimization of fluid viscous dampers for reducing vibrations of high-speed railway bridges JF - Journal of Sound and Vibration N2 - H∞ optimization of fluid viscous dampers for reducing vibrations of high-speed railway bridges KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 SP - 2421 EP - 2442 ER - TY - JOUR A1 - Schrader, Kai A1 - Könke, Carsten T1 - Hybrid computing models for large-scale heterogeneous 3d microstructures JF - International Journal for Multiscale Computational Engineering N2 - Hybrid computing models for large-scale heterogeneous 3d microstructures KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2011 SP - 365 EP - 377 ER - TY - JOUR A1 - Savaidis, G. A1 - Vormwald, Michael T1 - Hot-spot stress evaluation of fatigue in welded structural connections supported by finite element analysis JF - International Journal of Fatigue N2 - Hot-spot stress evaluation of fatigue in welded structural connections supported by finite element analysis KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2000 SP - 85 EP - 91 ER - TY - JOUR A1 - Xu, G. A1 - Mourrain, B. A1 - Galligo, A. A1 - Rabczuk, Timon T1 - High-quality construction of analysis-suitable trivariate NURBS solids by reparameterization methods JF - Computational Mechanics N2 - High-quality construction of analysis-suitable trivariate NURBS solids by reparameterization methods KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 ER - TY - JOUR A1 - Achenbach, Marcus A1 - Lahmer, Tom A1 - Morgenthal, Guido T1 - Global Sensitivity Analysis of Reinforced Concrete Walls Subjected to Standard Fire - A Comparison of Methods JF - 14th International Probabilistic Workshop N2 - Global Sensitivity Analysis of Reinforced Concrete Walls Subjected to Standard Fire—A Comparison of Methods KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2017 SP - 97 EP - 106 ER - TY - JOUR A1 - Nguyen-Tuan, Long A1 - Lahmer, Tom A1 - Datcheva, Maria A1 - Schanz, Tom T1 - Global and local sensitivity analyses for coupled thermo‐hydro‐mechanical problems JF - International Journal for Numerical and Analytical Methods in Geomechanics N2 - Global and local sensitivity analyses for coupled thermo‐hydro‐mechanical problems KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2016 ER - TY - JOUR A1 - Nguyen-Thoi, T. A1 - Rabczuk, Timon A1 - Lam-Phat, T. A1 - Ho-Huu, V. A1 - Phung-Van, P. T1 - Free vibration analysis of cracked Mindlin plate using an extended cell-based smoothed discrete shear gap method (XCS-DSG3) JF - Theoretical and Applied Fracture Mechanics N2 - Free vibration analysis of cracked Mindlin plate using an extended cell-based smoothed discrete shear gap method (XCS-DSG3) KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 ER - TY - JOUR A1 - Nguyen-Thoi, T. A1 - Phung-Van, P. A1 - Rabczuk, Timon A1 - Nguyen-Xuan, Hung A1 - Le-Van, C. T1 - Free and forced vibration analysis using the n-sided polygonal cell-based smoothed finite element method (nCS-FEM) JF - International Journal of Computational Methods N2 - Free and forced vibration analysis using the n-sided polygonal cell-based smoothed finite element method (nCS-FEM) KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Areias, Pedro A1 - Rabczuk, Timon A1 - Cesar de Sa, J.M. A1 - Garcao, J.E. T1 - Finite strain quadrilateral shell using least-squares _t of relative Lagrangian in-plane strains JF - Finite Elements in Analysis and Design N2 - Finite strain quadrilateral shell using least-squares _t of relative Lagrangian in-plane strains KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2015 SP - 26 EP - 40 ER - TY - JOUR A1 - Areias, Pedro A1 - Rabczuk, Timon T1 - Finite strain fracture of plates and shells with configurational forces and edge rotation JF - International Journal for Numerical Methods in Engineering N2 - Finite strain fracture of plates and shells with configurational forces and edge rotation KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2013 ER - TY - JOUR A1 - Areias, Pedro A1 - Rabczuk, Timon A1 - Camanho, P.P. T1 - Finite strain fracture of 2D problems with injected anisotropic softening elements JF - Theoretical and Applied Fracture Mechanics N2 - Finite strain fracture of 2D problems with injected anisotropic softening elements KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 ER - TY - JOUR A1 - Lahmer, Tom A1 - Kaltenbacher, Manfred A1 - Kaltenbacher, Barbara A1 - Lerch, Reinhard A1 - Leder, Erich T1 - Fem-based determination of real and complex elastic, dielectric, and piezoelectric moduli in piezoceramic materials JF - IEEE transactions on ultrasonics, ferroelectrics, and frequency control N2 - Fem-based determination of real and complex elastic, dielectric, and piezoelectric moduli in piezoceramic materials. KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2008 U6 - http://dx.doi.org/10.25643/bauhaus-universitaet.3594 ER - TY - JOUR A1 - Jia, Yue A1 - Anitescu, Cosmin A1 - Ghorashi, Seyed Shahram A1 - Rabczuk, Timon A1 - Dias-da-Costa, D. T1 - Extended Isogeometric Analysis for Material Interface Problems JF - Journal of Applied Mathematics N2 - Extended Isogeometric Analysis for Material Interface Problems KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2014 ER - TY - JOUR A1 - Chen, Lei A1 - Rabczuk, Timon A1 - Liu, G.R. A1 - Zeng, K.Y. A1 - Kerfriden, Pierre A1 - Bordas, Stéphane Pierre Alain T1 - Extended finite element method with edge-based strain smoothing (ESm-XFEM) for linear elastic crack growth JF - Computer Methods in Applied Mechanics and Engineering N2 - This paper presents a strain smoothing procedure for the extended finite element method (XFEM). The resulting “edge-based” smoothed extended finite element method (ESm-XFEM) is tailored to linear elastic fracture mechanics and, in this context, to outperform the standard XFEM. In the XFEM, the displacement-based approximation is enriched by the Heaviside and asymptotic crack tip functions using the framework of partition of unity. This eliminates the need for the mesh alignment with the crack and re-meshing, as the crack evolves. Edge-based smoothing (ES) relies on a generalized smoothing operation over smoothing domains associated with edges of simplex meshes, and produces a softening effect leading to a close-to-exact stiffness, “super-convergence” and “ultra-accurate” solutions. The present method takes advantage of both the ES-FEM and the XFEM. Thanks to the use of strain smoothing, the subdivision of elements intersected by discontinuities and of integrating the (singular) derivatives of the approximation functions is suppressed via transforming interior integration into boundary integration. Numerical examples show that the proposed method improves significantly the accuracy of stress intensity factors and achieves a near optimal convergence rate in the energy norm even without geometrical enrichment or blending correction. KW - Angewandte Mathematik KW - Strukturmechanik Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.cma.2011.08.013 ER -