Multiscale analysis of microcrack / macrocrack interaction

UVS
12. November 2009

Im Rahmen der Vortragsreihe des SFB 528 spricht am 16. November Stefan Löhnert vom Institute of Continuum Mechanics, Hannover, zum Thema „Multiscale analysis of microcrack / macrocrack interaction“. Der Vortrag findet im Beyer-Bau, Raum 67 statt und beginnt um 10 Uhr. Hier der Abstract des Autoren:

Large scale structures often fail due to cracks that start developing on a micro scale. The microstructure in the vicinity of a propagating crack has a significant influence on the propagation behavior. Due to the localization effect, in the vicinity of a propagating crack front homogenization methods based on the representative volume element concept usually fail since the representativeness of the volume element is lost. Thus, it is necessary to apply multiscale techniques that are capable of handling localization phenomena.

Here we present an adaptive multiscale projection method that can capture the influence of the microstructure on the crack propagation within a large scale structure correctly. The microstructure itself is modeled explicitly only on the fine scale. Its effects however are projected onto the coarse scale. The microscale domain is adapted to the domain of influence of the microstructure on the propagation of a macrocrack. In case of multiple fine scale domains, each domain can be simulated independently and in parallel. Thus the multiscale technique allows for the efficient and accurate simulation of general fine scale fracture processes. Microstructural effects such as crack shielding and crack amplification in two and three dimensions are reflected correctly. In order to further improve the accuracy of the simulation, the modified XFEM technique is employed in two and three dimensions. Different aspects of that extension of the XFEM in the context of three dimensions as well as the multiscale technique are addressed. The effects of finite deformations in two and three dimensions are investigated. Examples are shown for brittle material behavior and small as well as finite deformations.

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