Experimentally based modelling of failure mechanisms of high-strength concrete under multi-axial loading - MABET

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Failure simulations of thee-dimensionally loaded concrete structures are challenging till this date. Existing material models are often defined by model parameters which are no physically measurable quantities. Often, they can only be determined by mathematical calibration to known test results. Therefore, the application of existing material models is often limited to the recalculation of known experiments. Especially for the case of three-dimensional material models, the mutual influence of stresses and strains on the mechanical properties of all directions is neglected or simplified to a large extend. Additional experimental information is usually missing for the formulation of new three-dimensional evolution laws.A new material model is to be developed and validated experimentally in the present project. It will be suitable for failure simulations of high-strength concrete structures under multiaxial loading. A new measurement technique will be applied and tested for the experimental study of multiaxial deformation states. Continuous strain measurements with a new type of fiber optical sensors will provide new information on the strain distribution in the interior of concrete specimens. Thus, a re-assessment of the current knowledge on meso- and macro-models for concrete will become possible. The new material model will be able to describe the structural behavior, the state of damage and the failure mechanisms of thee-dimensionally loaded concrete in a correct physical manner. The model will provide the capability of a future extension to account for fatigue failure. Preliminary work of the applicants indicates that a strain or energy based formulation of the material law enables the definition of evolution laws and failure surfaces, which are mainly defined by physically measurable parameters. The subsequent implementation of the material model in a finite element program will enable a failure simulation of real structures under three-dimensional stresses. Numerous practical applications, such as the anchorage of concentrated loads in high-strength concrete or the grouted joints in offshore wind turbines, reveal the demand for such models.The cooperation between the research groups of the Technische Universität Berlin, with a focus on theoretical modeling, and Technische Universität Dresden, with a focus on experimental research, opens up a high synergy potential.