Bonded composite repair structures multiple site damage analysis

Purpose – The purpose of this work is to describe the effects of the length of cracks and the patch size on the stress intensity factors in a bonded composite repair structure containing multiple site damage. Design/methodology/approach – Finite element method was applied to simulate a bonded repair of a cracked aluminum plate with multiple site damage. A two-dimensional three-layer technique was utilized to model damage in a typical aluminum plate with collinear twin cracks. Findings – This research has found that the stress intensity factors of collinear twin cracks can be reduced significantly through bonded composite repair, and their values strongly depend on the relative position of the cracks. Moreover, the composite patch should be 1.5 to two times longer than the crack length and the patch thickness should be 30-40 percent of the plate thickness for the best repair performance. Research limitations/implications – Patch debonding can significantly reduce the repair efficiency and should be avoided if possible. Originality/value – It is seen that, instead of the three-dimensional finite element model, which is computationally intense, the two-dimensional three-layer finite element model has an adequate accuracy to obtain stress intensity factors in a bonded composite repair structure with multiple site damage.