Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Quelle der Hochschulschrift Konferenzname Quelle:Titel Quelle:Jahrgang Quelle:Heftnummer Quelle:Erste Seite Quelle:Letzte Seite URN DOI Abteilungen OPUS4-301 Konferenzveröffentlichung Häfner, Stefan; Eckardt, Stefan; Könke, Carsten A geometrical inclusion-matrix model for the finite element analysis of concrete at multiple scales This paper introduces a method to generate adequate inclusion-matrix geometries of concrete in two and three dimensions, which are independent of any specific numerical discretization. The article starts with an analysis on shapes of natural aggregates and discusses corresponding mathematical realizations. As a first prototype a two-dimensional generation of a mesoscale model is introduced. Particle size distribution functions are analysed and prepared for simulating an adequate three-dimensional representation of the aggregates within a concrete structure. A sample geometry of a three-dimensional test cube is generated and the finite element analysis of its heterogeneous geometry by a uniform mesh is presented. Concluding, aspects of a multiscale analysis are discussed and possible enhancements are proposed. 2003 urn:nbn:de:gbv:wim2-20111215-3018 10.25643/bauhaus-universitaet.301 Professur Informatik im Bauwesen OPUS4-3409 Wissenschaftlicher Artikel Eckardt, Stefan; Könke, Carsten Adaptive damage simulation of concrete using heterogeneous multiscale models Adaptive damage simulation of concrete using heterogeneous multiscale models 22 Journal of Algorithms & Computational Technology 275 297 Institut für Strukturmechanik (ISM) OPUS4-2947 Konferenzveröffentlichung Eckardt, Stefan; Könke, Carsten Gürlebeck, Klaus; Könke, Carsten ADAPTIVE SIMULATION OF THE DAMAGE BEHAVIOR OF CONCRETE USING HETEROGENEOUS MULTISCALE MODELS In this paper an adaptive heterogeneous multiscale model, which couples two substructures with different length scales into one numerical model is introduced for the simulation of damage in concrete. In the presented approach the initiation, propagation and coalescence of microcracks is simulated using a mesoscale model, which explicitly represents the heterogeneous material structure of concrete. The mesoscale model is restricted to the damaged parts of the structure, whereas the undamaged regions are simulated on the macroscale. As a result an adaptive enlargement of the mesoscale model during the simulation is necessary. In the first part of the paper the generation of the heterogeneous mesoscopic structure of concrete, the finite element discretization of the mesoscale model, the applied isotropic damage model and the cohesive zone model are briefly introduced. Furthermore the mesoscale simulation of a uniaxial tension test of a concrete prism is presented and own obtained numerical results are compared to experimental results. The second part is focused on the adaptive heterogeneous multiscale approach. Indicators for the model adaptation and for the coupling between the different numerical models will be introduced. The transfer from the macroscale to the mesoscale and the adaptive enlargement of the mesoscale substructure will be presented in detail. A nonlinear simulation of a realistic structure using an adaptive heterogeneous multiscale model is presented at the end of the paper to show the applicability of the proposed approach to large-scale structures. 15 urn:nbn:de:gbv:wim2-20170327-29478 10.25643/bauhaus-universitaet.2947 Institut für Strukturmechanik (ISM) OPUS4-2841 Konferenzveröffentlichung Eckardt, Stefan; Könke, Carsten Gürlebeck, Klaus; Könke, Carsten ENERGY RELEASE CONTROL FOR NONLINEAR MESOSCALE SIMULATIONS In nonlinear simulations the loading is, in general, applied in an incremental way. Path-following algorithms are used to trace the equilibrium path during the failure process. Standard displacement controlled solution strategies fail if snap-back phenomena occur. In this contribution, a path-following algorithm based on the dissipation of the inelastic energy is presented which allows for the simulation of snap-backs. Since the constraint is defined in terms of the internal energy, the algorithm is not restricted to continuum damage models. Furthermore, no a priori knowledge about the final damage distribution is required. The performance of the proposed algorithm is illustrated using nonlinear mesoscale simulations. 5 urn:nbn:de:gbv:wim2-20170314-28414 10.25643/bauhaus-universitaet.2841 Institut für Strukturmechanik (ISM) OPUS4-3460 Wissenschaftlicher Artikel Häfner, Stefan; Eckardt, Stefan; Luther, Torsten; Könke, Carsten Mesoscale modeling of concrete: Geometry and numerics Mesoscale modeling of concrete: Geometry and numerics 11 Computers and Structures 450 461 Institut für Strukturmechanik (ISM) OPUS4-3446 Wissenschaftlicher Artikel Unger, Jörg F.; Eckardt, Stefan; Könke, Carsten Modelling of cohesive crack growth in concrete structures with the extended finite element method Modelling of cohesive crack growth in concrete structures with the extended finite element method 13 Computer Methods in Applied Mechanics and Engineering 4087 4100 Institut für Strukturmechanik (ISM) OPUS4-3404 Wissenschaftlicher Artikel Könke, Carsten; Eckardt, Stefan; Häfner, Stefan; Luther, Torsten; Unger, Jörg F. Multiscale simulation methods in damage prediction of brittle and ductile materials Multiscale simulation methods in damage prediction of brittle and ductile materials 19 International Journal for Multiscale Computational Engineering 17 36 Institut für Strukturmechanik (ISM) OPUS4-3482 Wissenschaftlicher Artikel Bruhin, R.; Stock, U.A.; Drücker, J.-P.; Azhari, T.; Wippermann, J.; Albes, J.M.; Hintze, D.; Eckardt, Stefan; Könke, Carsten; Wahlers, T. Numerical simulation techniques to study the structural response of the human chest following median sternotomy Numerical simulation techniques to study the structural response of the human chest following median sternotomy 7 The Annals of Thoracic Surgery 623 630 Institut für Strukturmechanik (ISM)