Speaker
Description
This work focuses on the simulation-based determination of the effective crack resistance in het- erogeneous—and specifically porous—materials. We follow the approach of Hossain et al. [1] for a numerical experiment that enables the identification of effective crack resistance as a material parameter. Displacement boundary conditions corresponding to a steadily growing crack on the macroscopic scale are applied to a representative microstructure. On the microscale, crack growth is simulated without making a priori assumptions about crack paths, continuity of crack propagation, etc. The maximum value of the macroscopically acting J-integral represents the driving force necessary to advance the crack by a macroscopic length increment without crack arrest and is defined as the effective crack resistance.
For simulations on the representative microstructure without a priori assumptions about crack growth, phase-field models are particularly suitable and are therefore employed. Phase-field models introduce a regularized approximation of cracks and define an inherent length scale. In this work, we discuss the determination of the effective fracture toughness in metallic foams. The representative microstructures are obtained from CT scans of real materials. We examine the influence of various parameters on the effective crack resistance, with a particular focus on the interplay between the length scales of the phase-field model and the heterogeneities.
References
[1] M. Z. Hossain, C. J. Hsueh, B. Bourdin, K. Bhattacharya, Effective toughness of heterogeneous media, Journal of Mechanics and Physics of Solids 71, pp. 15–32
