@phdthesis{Ahmad, author = {Ahmad, Sofyan}, title = {Reference Surface-Based System Identification}, doi = {10.25643/bauhaus-universitaet.2113}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20140205-21132}, school = {Bauhaus-Universit{\"a}t Weimar}, pages = {153}, abstract = {Environmental and operational variables and their impact on structural responses have been acknowledged as one of the most important challenges for the application of the ambient vibration-based damage identification in structures. The damage detection procedures may yield poor results, if the impacts of loading and environmental conditions of the structures are not considered. The reference-surface-based method, which is proposed in this thesis, is addressed to overcome this problem. In the proposed method, meta-models are used to take into account significant effects of the environmental and operational variables. The usage of the approximation models, allows the proposed method to simply handle multiple non-damaged variable effects simultaneously, which for other methods seems to be very complex. The input of the meta-model are the multiple non-damaged variables while the output is a damage indicator. The reference-surface-based method diminishes the effect of the non-damaged variables to the vibration based damage detection results. Hence, the structure condition that is assessed by using ambient vibration data at any time would be more reliable. Immediate reliable information regarding the structure condition is required to quickly respond to the event, by means to take necessary actions concerning the future use or further investigation of the structures, for instance shortly after extreme events such as earthquakes. The critical part of the proposed damage detection method is the learning phase, where the meta-models are trained by using input-output relation of observation data. Significant problems that may encounter during the learning phase are outlined and some remedies to overcome the problems are suggested. The proposed damage identification method is applied to numerical and experimental models. In addition to the natural frequencies, wavelet energy and stochastic subspace damage indicators are used.}, subject = {System Identification}, language = {en} } @article{AreiasRabczuk, author = {Areias, Pedro and Rabczuk, Timon}, title = {Finite strain fracture of plates and shells with configurational forces and edge rotation}, series = {International Journal for Numerical Methods in Engineering}, journal = {International Journal for Numerical Methods in Engineering}, abstract = {Finite strain fracture of plates and shells with configurational forces and edge rotation}, subject = {Angewandte Mathematik}, language = {en} } @article{AreiasRabczukDiasdaCosta, author = {Areias, Pedro and Rabczuk, Timon and Dias-da-Costa, D.}, title = {Assumed-metric spherically-interpolated quadrilateral shell element}, series = {Finite Elements in Analysis and Design}, journal = {Finite Elements in Analysis and Design}, pages = {53 -- 67}, abstract = {Assumed-metric spherically-interpolated quadrilateral shell element}, subject = {Angewandte Mathematik}, language = {en} } @article{AreiasRabczukDiasdaCosta, author = {Areias, Pedro and Rabczuk, Timon and Dias-da-Costa, D.}, title = {Asymmetric Shell Elements Based on a Corrected Updated-Lagrangian Approach}, series = {CMES: Computer Modeling in Engineering and Sciences}, journal = {CMES: Computer Modeling in Engineering and Sciences}, abstract = {Asymmetric Shell Elements Based on a Corrected Updated-Lagrangian Approach}, subject = {Angewandte Mathematik}, language = {en} } @article{BakarKramerBordasetal., author = {Bakar, I. and Kramer, O. and Bordas, St{\´e}phane Pierre Alain and Rabczuk, Timon}, title = {Optimization of Elastic Properties and Weaving Patterns of Woven Composites}, series = {Composite Structures}, journal = {Composite Structures}, pages = {575 -- 591}, abstract = {Optimization of Elastic Properties and Weaving Patterns of Woven Composites}, subject = {Angewandte Mathematik}, language = {en} } @article{BanihaniRabczukAlmomani, author = {Banihani, Suleiman and Rabczuk, Timon and Almomani, Thakir}, title = {POD for real-time simulation of hyperelastic soft biological tissue using the point collocation method of finite spheres}, series = {Mathematical Problems in Engineering}, journal = {Mathematical Problems in Engineering}, doi = {10.1155/2013/386501}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170413-31203}, abstract = {The point collocation method of finite spheres (PCMFS) is used to model the hyperelastic response of soft biological tissue in real time within the framework of virtual surgery simulation. The proper orthogonal decomposition (POD) model order reduction (MOR) technique was used to achieve reduced-order model of the problem, minimizing computational cost. The PCMFS is a physics-based meshfree numerical technique for real-time simulation of surgical procedures where the approximation functions are applied directly on the strong form of the boundary value problem without the need for integration, increasing computational efficiency. Since computational speed has a significant role in simulation of surgical procedures, the proposed technique was able to model realistic nonlinear behavior of organs in real time. Numerical results are shown to demonstrate the effectiveness of the new methodology through a comparison between full and reduced analyses for several nonlinear problems. It is shown that the proposed technique was able to achieve good agreement with the full model; moreover, the computational and data storage costs were significantly reduced.}, subject = {Chirurgie}, language = {en} } @article{JiangParkGalletal., author = {Jiang, Jin-Wu and Park, Harold S. and Gall, K. and Leach, A. and Rabczuk, Timon}, title = {A Surface Stacking Fault Energy Approach to Predicting Defect Nucleation in Surface-Dominated Nanostructures}, series = {Journal of the Mechanics and Physics of Solids}, journal = {Journal of the Mechanics and Physics of Solids}, abstract = {A Surface Stacking Fault Energy Approach to Predicting Defect Nucleation in Surface-Dominated Nanostructures}, subject = {Angewandte Mathematik}, language = {en} } @article{JiangRabczuk, author = {Jiang, Jin-Wu and Rabczuk, Timon}, title = {Mechanical Oscillation of Kinked Silicon Nanowires: a Natural Nanoscale Spring}, series = {Applied Physics Letters}, journal = {Applied Physics Letters}, abstract = {Mechanical Oscillation of Kinked Silicon Nanowires: a Natural Nanoscale Spring}, subject = {Angewandte Mathematik}, language = {en} } @article{JiangRabczuk, author = {Jiang, Jin-Wu and Rabczuk, Timon}, title = {Modulation of Thermal Conductivity in kinked Silicon Nanowires: Phonon interchanging and pinching effects or Reduction of thermal conductivity in kinked silicon nanowire superlattices}, series = {Nano Letters}, journal = {Nano Letters}, abstract = {Modulation of Thermal Conductivity in kinked Silicon Nanowires: Phonon interchanging and pinching effects or Reduction of thermal conductivity in kinked silicon nanowire superlattices}, subject = {Angewandte Mathematik}, language = {en} } @article{JiangWangRabczuk, author = {Jiang, Jin-Wu and Wang, Bing-Shen and Rabczuk, Timon}, title = {Why twisting angles are diverse in graphene Moir'e patterns?}, series = {Journal of Applied Physics}, journal = {Journal of Applied Physics}, abstract = {Why twisting angles are diverse in graphene Moir'e patterns?}, subject = {Angewandte Mathematik}, language = {en} } @article{JiangZhaoRabczuk, author = {Jiang, Jin-Wu and Zhao, Jun-Hua and Rabczuk, Timon}, title = {Size-Sensitive Young's Modulus of Kinked Silicon Nanowires}, series = {Nanotechnology}, journal = {Nanotechnology}, doi = {10.1088/0957-4484/24/18/185702}, abstract = {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.}, subject = {Angewandte Mathematik}, language = {en} } @article{JiangZhuangRabczuk, author = {Jiang, Jin-Wu and Zhuang, Xiaoying and Rabczuk, Timon}, title = {Orientation dependent thermal conductance in single-layer MoS 2}, series = {Scientific Reports}, journal = {Scientific Reports}, doi = {10.1038/srep02209}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20170418-31417}, abstract = {We investigate the thermal conductivity in the armchair and zigzag MoS2 nanoribbons, by combining the non-equilibrium Green's function approach and the first-principles method. A strong orientation dependence is observed in the thermal conductivity. Particularly, the thermal conductivity for the armchair MoS2 nanoribbon is about 673.6 Wm-1 K-1 in the armchair nanoribbon, and 841.1 Wm-1 K-1 in the zigzag nanoribbon at room temperature. By calculating the Caroli transmission, we disclose the underlying mechanism for this strong orientation dependence to be the fewer phonon transport channels in the armchair MoS2 nanoribbon in the frequency range of [150, 200] cm-1. Through the scaling of the phonon dispersion, we further illustrate that the thermal conductivity calculated for the MoS2 nanoribbon is esentially in consistent with the superior thermal conductivity found for graphene.}, subject = {Mechanische Eigenschaft}, language = {en} } @article{KerfridenGouryRabczuketal., author = {Kerfriden, Pierre and Goury, O. and Rabczuk, Timon and Bordas, St{\´e}phane Pierre Alain}, title = {A partitioned model order reduction approach to rationalise computational expenses in nonlinear fracture mechanics}, series = {Computer Methods in Applied Mechanics and Engineering}, journal = {Computer Methods in Applied Mechanics and Engineering}, pages = {169 -- 188}, abstract = {A partitioned model order reduction approach to rationalise computational expenses in nonlinear fracture mechanics}, subject = {Angewandte Mathematik}, language = {en} } @article{KerfridenSchmidtRabczuketal., author = {Kerfriden, Pierre and Schmidt, K.M. and Rabczuk, Timon and Bordas, St{\´e}phane Pierre Alain}, title = {Statistical extraction of process zones and representative subspaces in fracture of random composites}, series = {International Journal for Multiscale Computational Engineering}, journal = {International Journal for Multiscale Computational Engineering}, abstract = {Statistical extraction of process zones and representative subspaces in fracture of random composites}, subject = {Angewandte Mathematik}, language = {en} } @article{KhosravaniRabczuk, author = {Khosravani, M.R. and Rabczuk, Timon}, title = {Determiniation of shear modulus for double and multi-walled Carbon Nanotubes}, series = {Mechanics of Composite Materials}, journal = {Mechanics of Composite Materials}, abstract = {Determiniation of shear modulus for double and multi-walled Carbon Nanotubes}, subject = {Angewandte Mathematik}, language = {en} } @article{KnabeDatchevaLahmeretal., author = {Knabe, Tina and Datcheva, Maria and Lahmer, Tom and Cotecchia, F. and Schanz, Tom}, title = {Identification of constitutive parameters of soil using an optimization strategy and statistical analysis}, series = {Computers and Geotechnics}, journal = {Computers and Geotechnics}, pages = {143 -- 157}, abstract = {Identification of constitutive parameters of soil using an optimization strategy and statistical analysis}, subject = {Angewandte Mathematik}, language = {en} } @article{LeNguyenXuanAskesetal., author = {Le, C.V. and Nguyen-Xuan, Hung and Askes, H. and Rabczuk, Timon and Nguyen-Thoi, T.}, title = {Computation of limit load using edge-based smoothed finite element method and second-order cone programming}, series = {International Journal of Computational Methods}, journal = {International Journal of Computational Methods}, abstract = {Computation of limit load using edge-based smoothed finite element method and second-order cone programming}, subject = {Angewandte Mathematik}, language = {en} } @article{NanthakumarLahmerRabczuk, author = {Nanthakumar, S.S. and Lahmer, Tom and Rabczuk, Timon}, title = {Detection of flaws in piezoelectric structures using extended FEM}, series = {International Journal for Numerical Methods in Engineering}, journal = {International Journal for Numerical Methods in Engineering}, pages = {373 -- 389}, abstract = {Detection of flaws in piezoelectric structures using extended FEM}, subject = {Angewandte Mathematik}, language = {en} } @article{NguyenThoiPhungVanRabczuketal., author = {Nguyen-Thoi, T. and Phung-Van, P. and Rabczuk, Timon and Nguyen-Xuan, Hung and Le-Van, C.}, title = {An application of the ES-FEM in solid domain for dynamic analysis of 2D fluid-solid interaction problems}, series = {International Journal of Computational Methods}, journal = {International Journal of Computational Methods}, abstract = {An application of the ES-FEM in solid domain for dynamic analysis of 2D fluid-solid interaction problems}, subject = {Angewandte Mathematik}, language = {en} } @article{NguyenThoiPhungVanRabczuketal., author = {Nguyen-Thoi, T. and Phung-Van, P. and Rabczuk, Timon and Nguyen-Xuan, Hung and Le-Van, C.}, title = {Free and forced vibration analysis using the n-sided polygonal cell-based smoothed finite element method (nCS-FEM)}, series = {International Journal of Computational Methods}, journal = {International Journal of Computational Methods}, abstract = {Free and forced vibration analysis using the n-sided polygonal cell-based smoothed finite element method (nCS-FEM)}, subject = {Angewandte Mathematik}, language = {en} }