Seminars Graduate School SimTech: Summer Term 2012

Advanced scale bridging techniques towards computational material design

Hüsnü Dal, Christian Linder and Christian Miehe

Scale bridging techniques are of major importance for a physically based modeling of materials. They open the door towards the computational design of new advanced materials and can therefore be seen as one key ingredient of our SimTech Vision 1 entitled "From empirical material description towards computational material design".

The seminar gives an overview about recent advances of hierarchical and concurrent scale bridging techniques to bridge length- and time scales from the nano- to the macroscopic scale. The demonstrated methods include density functional theory calculations, the quasicontinuum method, molecular simulations and finite element simulations. A particular emphasis will be directed towards newly developed homogenization approaches for materials whose microstructure include evolving discontinuities.

Mathematical Modeling

Prof. Guido Schneider

Mathematical modeling is widely used in SimTech. The seminar consists of two parts. The first part is about some theoretical background, like closed and open systems, validity and verification, non-dimensionalization, asymptotic models, perturbation methods, scaling arguments, etc. In the second part examples will be treated. The modeling process will be analyzed and the tools of the first part will be applied. Students can choose their own SimTech project or examples provided by the organizer.

The seminar will take place in june and july. If you are interested please send an email with the title of your SimTech project to guido.schneider@mathematik.uni-stuttgart.de

Stochastic and Statistical Topics in Simulation Technology; Part 1: Numerical simulation of PDEs with random coefficients

Jun.-Prof. Wolfgang Nowak

I would like to invite all PhD students and PostDocs who are interested in modelling and simulation under uncertainty. The topics discussed in part one form the basis for Bayesian updating, robust design, probabilistic risk assessment, model criticism etc., to be dealt with in later parts of the seminar series.

For the current seminar, the goal is to get an overview over techniques that solve partial differential equations with random coefficients. Such problems occur in many fields of science and engineering, such as continuum mechanics, flow/transport in porous media, systems biology, etc., whenever leaving the often unrealistic assumption that one perfectly knows the system under investigation.

Topics: Representation of heterogeneity (random fields, principal components), (Quasi) Monte Carlo, linear error propagation methods, non-linear expansions methods (polynomial chaos etc), efficient high-dimensional integration, Model averaging,... ...to be expanded/adapted according to the preferences of the participants.

The Concept of Multiscale - Science beyond the bounds of isolated systems and methods

M. Richter, D. Molnar, JP U. Pompe and Prof. S. Schmauder

This interdisciplinary SimTech seminar tackles conceptual and technical problems that arise in the domains of multiscale modelling.

The major technical problem is to overcome the limitations of simulation methods describing phenomena on different length and time scales. Examples can be found in a variety of disciplines such as materials science (breaking of atomic bonds -> material failure), geosciences (carbon sequestration -> subsurface processes), bio science (chemical reactions -> muscle contraction) or sociology (single person -> populations), just to name a few.

In conceptual respects, this endeavour will be reflected against the background of broader epistemology as well as philosophy of science. Questions here are whether, and in what sense, reality can be conceived of as coupled layers or (from a more contemporary perspective) whether the conditions for understanding real world phenomena demand for a coupled-layer model.

Our seminar is a joint cooperation between the Institute for Materials Testing, Materials Science and Strength of Materials (IMWF) and the Institute of Philosophy (IP). The ultimate goal is to analyse different usages of the term multiscale and to reflect on the concept(s) behind. For this purpose, we will read and present a variety of publications concerning this issue. This shall pave the grounds for the mapping of different terminologies and for a wellreflected positioning in technical as well as conceptual respects. We cordially invite members of all SimTech Project Groups interested in the concept of multiscale modelling to participate.