Numerical Study for Optimum Parameters of Bonded Composite Repairs of Cracked Aluminum

Abstract

This thesis used Finite Element Analysis to model a cracked aluminum panel repaired with a bonded composite patch using the minimization of energy release rate in mode I crack growth conditions to determine effectiveness of a patch. The first phase of the study was to understand the mechanics of the effects of asymmetric or one-sided patching for both flat and curved geometries. The out of plane deflection that occurs due to one sided patching had a significant effect. Phase two studied the relationship between patch and base plate stiffness and patch and base plate thickness using orthotropic patch characteristics. Phase two provides general target patch design guidelines that could be used by technicians performing the repair. The third phase studied the effects of varying specific patch design parameters such as patch length and patch width applied to flat plate and curved geometries to provide specific design parameters to use in achieving general patch requirements determined from phase two of this study.