Regensburg 2016 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 50: Methods in Computational Materials Modelling II: Microstructure evolution

MM 50.3: Talk

Thursday, March 10, 2016, 10:45–11:00, H53

On the Propagation of two en passent cracks upon mutual interaction: A phase field study — •Michael Fleck, Markus Thäter, Martin Lautenschläger, and Heike Emmerich — Materials and Process Simulation, University of Bayreuth, Germany

A phase field model for the simulation of crack propagation in brittle materials is applied to the problem of two mutually interacting "en passent" cracks. Thereby, crack growth is described as a first order phase transformation process, where the solid parent phase transforms into an infinitely weak "broken" phase, driven by elastic energy dissipation. We discuss the problem of "en passent" cracks in a two dimensional plain strain geometry, subjected to a constant uniaxial pulling velocity of mode I type. Our model reproduces a number of basic features that are also observed in corresponding experimental setupsInitially, when the two cracks propagate independently, they approach each other along straight paths. Then, during the early stage of the mutual interaction and for certain geometrical circumstances the principle of local symmetry may even force the cracks to turn slightly away from each other. When the line connecting the two crack tips alines with the pulling direction, the two cracks curve towards each other upon mutual tip-tip interaction until each crack tip reaches the other’s crack tail, finally releasing a lenticular fragment. Here, we investigate the crack propagation dynamics as well as the chosen crack paths as a function of all relevant physical dependences, with the aim to elucidate the governing mechanisms that allow to classify the observed kinetics.