Finite Element Analysis and Test Validation of Composite Repair for 787 Airplanes

摘要

Two test methods have been chosen to characterize the effects of composite bonded repairs subject to bending and extension. Specifically, long beam flexure (LBF) and end loaded large panel (LP) specimens. Due to the presence of damage and patch repair, the stress-strain state is very complex and closed form solutions for stress-strain are not readily available except for a few special cases. That makes the interpretation of test results and understanding of the failure problematic. To better understand the specimens behaviors to identify the effects of damages, effectiveness of the patch, stress-strain state in the vicinity of the repair region and the factors controlling the failure to derive a technique for margin of safety calculation, finite element analysis (FEA) models with realistic representations of the damage and repair have been developed and validated to provide those insights.