Shape optimization of bonded patch to cylindrical shell structures

Adhesive bonding has been widely used to join or repair metallic and composite structural components to achieve or restore their designated structural sti ness and strengths. However, current analysis methods and empirical databases for composite bonded patch repairs or joints are limited to at structures, and there exists a very limited knowledge on the e ect of curvature on the performance and durability of composite bonded joints and repairs. Recently, a novel nite element formulation was presented for developing adhesive elements for conducting 2.5-D simpli ed stress analysis of bonded repairs to curved structures. This paper presents the work on optimal shape design of a bonded curved composite patch using the newly developed adhesive element. The Sequential Linear Programming (SLP) method is employed as the optimization algorithm in conjunction with a fully implemented mesh generation algorithm into which new features have been incorporated. The objective of shape optimization is to minimize the maximum stress in the entire adhesive layer to ensure that the bonded patch e ectively works together with the parent structure in service. Several di erent objective functions, related to possible failure mechanisms of the adhesive layer, are proposed to optimize the shape of a bonded patch.