Non-linear theory and adaptive FEM of martensitic phase transformation with technical application
|Bearbeitung:||Prof.em.Dr.-Ing.habil. Dr.-Ing.E.h. Dr.h.c. mult. Erwin Stein, M.Sc. Gautam Sagar|
|Förderung durch:||This work is financed by the German Research Foundation (DFG Ste/51- 1 & 2).|
Shape memory alloys (SMAs) are widely used in technical application, e.g. in medical science because of their wide range of properties, as super-elasticity (SE), shape memory (SM) and bio-compatibility. The efficient design of complicated devices is based on reliable simulation of material and structural behavior. Thus, it is very important to have a reliable material model at hand which can describe cyclic thermo-mechanical loadings close to the real behavior. Martensitic phase transformation is a strongly coupled thermo-mechanical process. A major problem is the convexification of energy wells in the process of minimizing the free energy for the active phases for multi-variant phases. Most research was done for linearlized strains but PT-strains are can reach up to 15% such that finite strain formulations are adequate. This project has following research points: (1) PT-model with finite strains for single crystals with convexification and phase balance, (2) Nonlinear PT-model for polycrystals, (3) Twinning, (4) Energy dissipation, (5) Implementation in ABAQUS, (6) Error controlled adaptive meshing, (7) Verification of developed PT-model and 8) Technological aplications of industrial problems.