Comparison of mechanical properties of precured-patch scarf repaired and wet-layup scarf repaired laminates

Abstract

Scarf repair is a widely used repair method for damaged composite structures, which can be divided into two categories: dry (precured-patch) repair and wet (wet-layup) repair. The ultimate strength, failure mode and patch debonding of scarf repaired composite laminates were studied by static tensile test. The specimens with different damage sizes were repaired by dry repair and wet repair method. The experimental results show that the higher recovery of failure strength and the lower probability of patch debonding can be obtained by using precured-patch repair method. Based on the experimental investigation, finite element analysis was carried out to accurately predict the ultimate strength, stress-strain distribution and damage evolution process of scarf repaired laminates. The simulation results show that the use of precured-patch repair can improve the mechanical performance of the repaired laminates compared to that using wet-layup repair. The stress distribution of the bondline is more uniform, the stress level and stress concentration are lower, and the load of interface failure and cohesive failure are higher.

Keywords

• composite laminates
• scarf repair
• progressive damage model
• finite element analysis