Computational Mechanics:
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Project leader: Christoph Adam
Institute for Basic Sciences in Civil Engineering - Unit for Applied Mechanics
The planned research in the field of “Computational Mechanics: Computational structural and soil dynamics” comprises the following projects:
The projects will benefit from the interdisciplinary approach of the DK+, because knowledge of the DK faculty members will become available in a structured manner. In particular the expertise of T. Fahringer (parallelization), G. Hofstetter (constitutive modelling), A. Ostermann (numerical stability), M. Oberguggenberger (probabilistic framework, Monte-Carlo simulation, random fields) will be integrated.
Computational Mechanics:
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This PhD- project concerns the investigation of the effect of dynamic instabilities in seismically excited structures. For simple structural models with non-deteriorating inelastic material behaviour a methodology has been developed to predict their structural seismic collapse capacity. The results are based on extensive numerical dynamic analyses and subsequent statistical evaluations involving a set of ground motions recorded during catastrophic earthquakes in order to capture the aleatory uncertainties due to the record-to-record variability. In a first step of the PhD project the effect of epistemic uncertainties due to the parameter variability on the seismic collapse capacity, which lead to an additional dispersion of the fragility curves, will be studied. Another source of structural collapse can be attributed to significant degradation of stiffness and strength during seismic excitation. An important further step is a combined consideration of dynamic instabilities and material deterioration. This requires sophisticated modelling of hysteretic structural behaviour. The essential parameters for the prediction of seismic collapse of structures will be determined. In particular, classes of structures, which allow a separated treatment of degrading material behaviour and dynamic instabilities, need to be identified. The derived results are based on Monte Carlo simulation procedure, which will be implemented in an OpenSource finite element code.
Computational Mechanics:
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In ground engineering appropriate compaction of layerwise built-in earth structure and its control is of particular significance, because the serviceability and structural safety of the complete building (road, rail tracks, foundations, etc.) connected to the earth structure are ensured. Within this DK-project a profound mechanical model for numerical simulation of soil compaction and its control will be established. The work includes refined non-linear constitutive modelling of the subsoil describing the effect of compaction, its implementation in an OpenSource finite element code, and selection of efficient computational solution procedures. The resulting model will be applied for the numerical simulation of dynamic soil compaction and its propagation into the soil depth by means of compaction devices. The impact of uncertainties and inhomogeneities of the soil will be studied considering random sets of soil parameters. Wave propagation on the surface and depth and its decay from the source of excitation will be simulated and subsequently compared with outcomes from large-scale in-situ tests.
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