THREE-DIMENSIONAL COHESIVE CRACK GROWTH MODELLING USING THE BEM

Resumo

The mechanical collapse of several materials is consistently modelled through the fracture
mechanics theories. The Linear Elastic Fracture Mechanics (LEFM) is properly utilized when the
fracture process zone ahead the crack tip is small in comparison with other structural dimensions.
Nevertheless, such zone is not small enough in various material types. Among them, it is worth citing
the composites, concrete and ceramics, which are generally classified as quasi-brittle materials. In this
case, the fracture process zone may be mechanically represented by the cohesive fracture approach,
which leads to the Nonlinear Fracture Mechanics. In the present study, the three-dimensional Boundary
Element Formulation (BEM) is coupled to the cohesive crack approach for modelling the nonlinear
fracture process of quasi-brittle materials. Moreover, three cohesive crack laws are utilized to represent
the residual material resistance at the fracture process zone. The nonlinear problem is solved by either
constant or tangent operators. The accuracy of the proposed BEM approach is demonstrated through
two applications. The results of the proposed numerical scheme are compared with numerical and
experimental responses available in the literature.