Sixth GAMM Seminar on Microstructures - Abstract
Gürses, Ercan
The lecture outlines a variational formulation of quasistatic brittle fracture in elastic solids and proposes a finite-element-based computational framework for propagation of cracks in three-dimensional bodies. The starting point is a variational setting of fracture mechanics that recasts a monotonic quasistatic fracture process into a sequence of incremental energy minimization problems. This extremum formulation includes the classical Griffith theory of brittle fracture. The proposed algorithm employs 4-noded linear tetrahedral elements and introduces discretized crack patterns with material-force-driven incremental nodal and crack surface releases. These releases of crack facets constitute a sequence of positive definite subproblems with successively decreasing overall stiffness, providing an extremely robust algorithmic setting in the postcritical range. The formulation is also embedded into an accompanying r-adaptive crack-pattern adjustment procedure with material-force-based indicators in conjunction with crack front constraints. The adjustment procedure allows reorientations of finite elements at the crack-front providing a considerable improvement in the predictions of it curved crack surfaces when compared with the experimental observations. The capabilities of the proposed algorithm will be demonstrated by means of several three-dimensional crack propagation examples and comparisons with experiments.