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 - CHAP A1 - Alalade, Muyiwa A1 - Kafle, Binod A1 - Wuttke, Frank A1 - Lahmer, Tom ED - Gürlebeck, Klaus ED - Lahmer, Tom T1 - CALIBRATION OF CYCLIC CONSTITUTIVE MODELS FOR SOILS BY OSCILLATING FUNCTIONS T2 - Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 20 - 22 2015, Bauhaus-University Weimar N2 - In order to minimize the probability of foundation failure resulting from cyclic action on structures, researchers have developed various constitutive models to simulate the foundation response and soil interaction as a result of these complex cyclic loads. The efficiency and effectiveness of these model is majorly influenced by the cyclic constitutive parameters. Although a lot of research is being carried out on these relatively new models, little or no details exist in literature about the model based identification of the cyclic constitutive parameters. This could be attributed to the difficulties and complexities of the inverse modeling of such complex phenomena. A variety of optimization strategies are available for the solution of the sum of least-squares problems as usually done in the field of model calibration. However for the back analysis (calibration) of the soil response to oscillatory load functions, this paper gives insight into the model calibration challenges and also puts forward a method for the inverse modeling of cyclic loaded foundation response such that high quality solutions are obtained with minimum computational effort. Therefore model responses are produced which adequately describes what would otherwise be experienced in the laboratory or field. KW - Angewandte Informatik KW - Angewandte Mathematik KW - Building Information Modeling KW - Computerunterstütztes Verfahren KW - Data, information and knowledge modeling in civil engineering; Function theoretic methods and PDE in engineering sciences; Mathematical methods for (robotics and) computer vision; Numerical modeling in engineering; Optimization in engineering applications Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170314-27932 SN - 1611-4086 ER - TY - JOUR A1 - Alalade, Muyiwa A1 - Nguyen-Tuan, Long A1 - Wuttke, Frank A1 - Lahmer, Tom T1 - Damage identification in gravity dams using dynamic coupled hydro-mechanical XFEM JF - International Journal of Mechanics and Materials in Design N2 - Damage identification in gravity dams using dynamic coupled hydro-mechanical XFEM. KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2017 U6 - http://dx.doi.org/10.25643/bauhaus-universitaet.3596 SP - 1 EP - 19 ER - TY - JOUR A1 - Ghorashi, Seyed Shahram A1 - Lahmer, Tom A1 - Bagherzadeh, Amir Saboor A1 - Zi, Goangseup A1 - Rabczuk, Timon T1 - A stochastic computational method based on goal-oriented error estimation for heterogeneous geological materials JF - Engineering Geology N2 - A stochastic computational method based on goal-oriented error estimation for heterogeneous geological materials KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2016 ER - TY - CHAP A1 - Ghorashi, Seyed Shahram A1 - Rabczuk, Timon A1 - Ródenas García, Juan José A1 - Lahmer, Tom ED - Gürlebeck, Klaus ED - Lahmer, Tom ED - Werner, Frank T1 - T-SPLINE BASED XIGA FOR ADAPTIVE MODELING OF CRACKED BODIES T2 - Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 04 - 06 2012, Bauhaus-University Weimar N2 - Safety operation of important civil structures such as bridges can be estimated by using fracture analysis. Since the analytical methods are not capable of solving many complicated engineering problems, numerical methods have been increasingly adopted. In this paper, a part of isotropic material which contains a crack is considered as a partial model and the proposed model quality is evaluated. EXtended IsoGeometric Analysis (XIGA) is a new developed numerical approach [1, 2] which benefits from advantages of its origins: eXtended Finite Element Method (XFEM) and IsoGeometric Analysis (IGA). It is capable of simulating crack propagation problems with no remeshing necessity and capturing singular field at the crack tip by using the crack tip enrichment functions. Also, exact representation of geometry is possible using only few elements. XIGA has also been successfully applied for fracture analysis of cracked orthotropic bodies [3] and for simulation of curved cracks [4]. XIGA applies NURBS functions for both geometry description and solution field approximation. The drawback of NURBS functions is that local refinement cannot be defined regarding that it is based on tensorproduct constructs unless multiple patches are used which has also some limitations. In this contribution, the XIGA is further developed to make the local refinement feasible by using Tspline basis functions. Adopting a recovery based error estimator in the proposed approach for evaluation of the model quality and performing the adaptive processes is in progress. Finally, some numerical examples with available analytical solutions are investigated by the developed scheme. KW - Angewandte Informatik KW - Angewandte Mathematik KW - Computerunterstütztes Verfahren Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170314-27637 UR - http://euklid.bauing.uni-weimar.de/ikm2012 SN - 1611-4086 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 - CHAP A1 - Göbel, Luise A1 - Osburg, Andrea A1 - Lahmer, Tom ED - Gürlebeck, Klaus ED - Lahmer, Tom T1 - STUDY OF ANALYTICAL MODELS OF THE MECHANICAL BEHAVIOR OF POLYMER-MODIFIED CONCRETE T2 - Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 20 - 22 2015, Bauhaus-University Weimar N2 - Polymer modification of mortar and concrete is a widely used technique in order to improve their durability properties. Hitherto, the main application fields of such materials are repair and restoration of buildings. However, due to the constant increment of service life requirements and the cost efficiency, polymer modified concrete (PCC) is also used for construction purposes. Therefore, there is a demand for studying the mechanical properties of PCC and entitative differences compared to conventional concrete (CC). It is significant to investigate whether all the assumed hypotheses and existing analytical formulations about CC are also valid for PCC. In the present study, analytical models available in the literature are evaluated. These models are used for estimating mechanical properties of concrete. The investigated property in this study is the modulus of elasticity, which is estimated with respect to the value of compressive strength. One existing database was extended and adapted for polymer-modified concrete mixtures along with their experimentally measured mechanical properties. Based on the indexed data a comparison between model predictions and experiments was conducted by calculation of forecast errors. KW - Angewandte Informatik KW - Angewandte Mathematik KW - Building Information Modeling KW - Computerunterstütztes Verfahren KW - Data, information and knowledge modeling in civil engineering; Function theoretic methods and PDE in engineering sciences; Mathematical methods for (robotics and) computer vision; Numerical modeling in engineering; Optimization in engineering applications Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170314-27973 SN - 1611-4086 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 - CHAP A1 - Hartmann, Veronika A1 - Smarsly, Kay A1 - Lahmer, Tom ED - Gürlebeck, Klaus ED - Lahmer, Tom T1 - ROBUST SCHEDULING IN CONSTRUCTION ENGINEERING T2 - Digital Proceedings, International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering : July 20 - 22 2015, Bauhaus-University Weimar N2 - In construction engineering, a schedule’s input data, which is usually not exactly known in the planning phase, is considered deterministic when generating the schedule. As a result, construction schedules become unreliable and deadlines are often not met. While the optimization of construction schedules with respect to costs and makespan has been a matter of research in the past decades, the optimization of the robustness of construction schedules has received little attention. In this paper, the effects of uncertainties inherent to the input data of construction schedules are discussed. Possibilities are investigated to improve the reliability of construction schedules by considering alternative processes for certain tasks and by identifying the combination of processes generating the most robust schedule with respect to the makespan of a construction project. KW - Angewandte Informatik KW - Angewandte Mathematik KW - Building Information Modeling KW - Computerunterstütztes Verfahren KW - Data, information and knowledge modeling in civil engineering; Function theoretic methods and PDE in engineering sciences; Mathematical methods for (robotics and) computer vision; Numerical modeling in engineering; Optimization in engineering applications Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20170314-27994 SN - 1611-4086 ER - TY - JOUR A1 - Hauck, A. A1 - Lahmer, Tom A1 - Kaltenbacher, Manfred T1 - Enhanced homogenization technique for magnetomechanical systems using the generalized finite element method JF - COMPEL: The international journal for computation and mathematics in electrical and electronic engineering N2 - Enhanced homogenization technique for magnetomechanical systems using the generalized finite element method KW - Angewandte Mathematik KW - Stochastik KW - Strukturmechanik Y1 - 2009 SP - 935 EP - 947 ER -