Buildup of anamnesis and swept out of memory under coupling of monotonic and cyclic loading

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The aim of this project is to develop a method to couple a cyclic explicit constitutive model inparallel with a non-linear monotonic material model. The evolution of the historiotropic state variables used by both the monotonic and the cyclic models should be described by this coupling. These evolution equations should allow the buildup of material memory (anamnesis) and/or its degradation depending on the loading conditions. The mechanical soil behavior is strongly influenced by the loading history (i.e. stress/strain path dependency). The soil adapts its internal structure to the applied loads and each load change causes a reorganization of force chains in the soil skeleton. This reorganization can be regarded as some kind of buildup or degradation of memory. The evolution laws of this memory should be captured by the coupling model in the context of this research project. By way of example of the coupling, the hypoplastic and the HCA models are combined into a single constitutive equation, in which monotonic and cyclic loads can be simultaneously treated. In addition to the simultaneous (parallel) application of monotonic and cyclic loads, this coupling can describe the sequential (serial) alternation of monotonic and cyclic loads. By means of element tests the influence of different preloading (monotonic or cyclic) conditions on the evolution of the historiotropic variables can be studied and the required parameters calibrated. The predictive and explanatory potential of this coupling as well as the robustness of its numerical implementation should be demonstrated with the help of a finite element simulation of an exemplary boundary value problem.