The fracture failure of three-dimensional concrete structures subjected to concentrated loadings using the Boundary Element Method

Falha por fratura de estruturas em concreto submetidas a carregamentos concentrados pelo Método dos Elementos de Contorno

Abstract

This study applies the Boundary Element Method (BEM) for the fracture failure modelling of three-dimensional concrete structures subjected to concentrated boundary conditions. The non-requirement of domain mesh by the BEM enables high accuracy in the domain fields assessment in addition to less complex remeshing procedures during crack propagation. However, concentrated boundary conditions often occur in fracture mechanics. The Lagrangian version of the BEM enforces such boundary conditions approximately by small length elements, which lead to numerical instabilities or even inaccurate problem representation. This study proposes a formulation for representing properly concentrated boundary conditions within the Lagrangian BEM framework. Nonlinear fracture mechanics describes the material failure processes herein. The classical cohesive crack approach governs the nonlinear energy dissipation processes, in which constant and tangent operators solve the resulting nonlinear system. Three applications demonstrate the accuracy of the proposed formulation, in which the BEM responses are compared against numerical and experimental results available in the literature.

Keywords:
concentrated boundary conditions; nonlinear fracture mechanics; enrichment functions; three-dimensional fracture modelling