Constitutive Qualities of Materials

Responsible professors: Prof. Schanz; Prof. Stark; Prof. Dimmig-Osburg;  Prof. Rabczuk
Cooperating professors: Prof. Kornadt; Prof. Schwarz, Prof. Kaps, Prof. Kießl
Junior scientists: Dr. Bellmann, Dr. Rößler, Dr. Wuttke

As verification of usability and structural safety, the engineer must give a high-quality prediction of the structure, particularly of the material behaviour. Within the context of the application, materials with a crystalline microstructure (steel) and porous materials (polymer modifies concrete, clays) will be treated.

The central objective of the work described is the quantification of requirements for the degree of idealization of constitutive descriptions in accordance with their complexity (e.g. considering the texture, anisotropy, multi-phase qualitities etc.) and robustness, depending on the nature of each underlying question (e.g. Multifield, static or dynamic loads, etc.).

On different scales (meso-, micro- and nano-level), more complex constitutive relations lead increasingly to a removal of robustness and increase of obscure constitutive relations or parameters. Deterministic and stochastic approaches are used with regards to constitutive parameters. When using stochastic approaches an additional difficulty is often the generally unknown distribution of the constitutive parameters. In this application inverse methods and sensitivity analysis are used for its indirect, iterative determination (Cividini 1981; Maier et al 1997; Meier et al 2006). The quality statement will be at the level of partial models through their comparison with existing experimental results. In addition, the consequence of increasingly obscure constitutive parameters based on the evidence of the partial model is investigated on synthetic experiments.