Coupled Problems in Constitutive Modeling Across Various Lenght-Scales


Prof. Bjoern Kiefer, Ph.D.
Institute of Mechanics and Fluid Dynamics, TU Bergakademie Freiberg

Wednesday, 18.07.2018, 17:00
WW8, Raum 2.018, Dr.-Mack-Str. 77, Fürth

 This presentation gives an overview of our research activities regarding the computational mechanics of coupled problems, with a particular focus on constitutive modeling. This discussion will include both theoretical developments and related numerical treatments. Coupling phenomena in mechanics may arise for a number of reasons—e.g. due to mutually dependent field equations, or in the interplay of constitutive mechanism. The former is typically encountered in the context of multi-physics problems (thermo-, electo-, magneto- or chemo-mechanics) and other systems of coupled balance equations (diffusion-driven deformation, fluid-structure interaction), but also in higher-order continuum formulations (micromorphic, phase-field). In terms of material response, the behavior of many advanced engineering materials crucially depends on the coupling of mechanisms such as plasticity, damage, and solid-solid phase transformations. Another example are the unique properties of smart, active and multifunctional materials, which are enabled by multi-physical couplings (piezo-electricity or magnetism, multiferroic behavior). Moreover, both the field equations and the constitutive equations often exhibit coupling across many length-scales. In this context, we present our scientific work over the past years dedicated to establishing fundamental variational frameworks for the modeling and simulation of coupled material response, the solving of coupled field problems and for scale-bridging. Specific application  examples include the modeling of shape memory alloys, magneto-mechanical coupling (magnetostrictives, magnetic shape memory alloys, magneto-active polymers), gradient-enhanced damage-plasticity and a phase-field approach for cohesive fracture and fatigue.