Analysis of cracked body repaired by adhesively bonded patches by bem-fem coupling

Abstract

This thesis presents an efficient numerical technique capable of handling the stress analysis of three-dimensional cracked bodies strengthened or repaired by adhesively bonded patches. The proposed technique is implemented within the framework of the coupling of the weakly singular boundary integral equation method and the standard finite element procedure. The former is applied to efficiently treat the elastic body containing cracks whereas the latter is adopted to handle both the adhesive layers and the patches. The approximation of the near-front relative crack-face displacement is enhanced by using local interpolation functions that can capture the right asymptotic behaviour. This also offers the direct calculation of the stress intensity factors along the crack front in terms of solved nodal data. A selected set of results is reported to demonstrate the accuracy and convergence of the proposed technique and the influence of relative stiffness of the patches and adhesive layers on the reduction of the stress intensity factor along the crack front.