The multiple fatigue crack propagation modelling in nonhomogeneous structures using the DBEM

Abstract

This study describes a numerical approach for the simulation of multiple crack propagation in two-dimensional nonhomogeneous structures subjected to fatigue. The nonhomogeneous structural system is assumed as composed of piecewise homogeneous and isotropic materials. The high-cycle fatigue condition is assumed, which enables the use of the Linear Elastic Fracture Mechanics (LEFM). The mechanical behaviour is determined by the dual boundary element method (DBEM). The DBEM is a robust and efficient method for handling crack growth analyses because of the non-requirement of the domain mesh. This aspect enables the proper description of the elastic fields surrounding the crack tip. Moreover, it simplifies the remeshing procedures during the crack propagation. To couple adjacent materials forming the nonhomogeneous domain, the sub-region technique is used considering perfectly bonded interfaces. Regarding the fatigue, the crack growth rates are evaluated with the Paris' law. In addition, the structural life is assessed with a scheme based on discrete crack increments. The stress intensity factors at the crack tips are computed with the J-integral technique, whereas the crack propagation angle is defined with the LEFM theory. Four applications are presented to illustrate the accuracy and robustness of the proposed numerical approach for the multiple fatigue crack propagation modelling.