Deformation, Fatigue and Fracture

Research in this area is mostly based on experimental work, but also new conceptual ideas are developed, based on theoretical and/or numerical investigations. In the recent years, research has been expanded into new areas, such as the deformation and fracture behavior of materials at the micro- or nanoscale (see Micro- and Nanomechanics) and the deformation and the behavior of nanocrystalline materials that are produced by extremely high plastic deformation, see Nanomaterials by Severe Plastic Deformation.

A distinguishing feature of the experimental work at ESI has been the approach to resolve the microstructure-properties relationships by investigating the influence of the local microstructure on the local material behavior. Interdisciplinary research between the fields of materials science and digital image correlation has led to the development of experimental techniques that allow us to perform measurements of the local fracture initiation toughness from quantitative fracture surface analysis and to record the local damage evolution in materials by in-situ deformation- and fracture experiments in the scanning electron microscope.

  Scanning electron micrograph of a crack in a metal matrix composite (left) with distribution of local strains (right)

Interdisciplinary research, spanning the areas of materials science, mechanics and thermodynamics, has brought new impetus to the research in form of the application of the configurational forces concept. Configurational forces are thermodynamic forces that act on all types of defects in materials. We apply this concept for an improved description of the behavior of cracks in inhomogeneous materials and for fundamental investigations on the application of the J-integral in fracture and fatigue.