Influence of Patch Shape and Size on Adhesively Bonded Composite Repair

Abstract

Compared with the traditional mechanical repair technology, the adhesively bonded repairs in composites have the obvious advantages of less increment of structure weight, strong design ability, easy forming and low cost. Therefore, the technology of adhesively bonded repairs in composites has been successfully applied to some damaged structures of military and civilian aircraft. Based on the three-dimensional progressive damage theory, the models of adhesively bonded repairs are respectively established with different shapes of the patches by using the software of ANSYS. Motherboard and patch are established with the orthogonal anisotropic damage model, and adhesive is established with the isotropic damage model. Under uniaxial tensile load, at the same time, considering the damage form and the trends of expansion of the laminates and adhesive, the ultimate failure load is determined. The validity of the method is proved by comparing with previous references. The calculation results of damage model show that the patch shape and size, which have a great effect on the ultimate failure load of composite laminates, are important design parameters of adhesively bonded repairs. The effect of repair with tilted square patch is better than others. When the round-corner process of tilted square patch is conducted, the load-bearing capacity of damaged laminates is improved.