Analysis of the performance of carbon fiber patches on improving the failure strength of a damaged and repaired plate

Abstract

Since the implementation of the composite patch bonding repair technique, this process has gradually replaced the traditional methods of bolting or welding. The correct choice of fiber type for the composite patch ensures better repair durability. Carbon fiber composites, which are preferred for the most advanced aeronautical and industrial applications, have shown great effectiveness in reducing stresses at the damaged area. They are chosen for their high strength, low weight, and high stiffness, compared to other fibers. This work consists of a finite element method to evaluate the performance of carbon fiber composite patches (high-modulus fiber and high-strength fiber) for load transfer and thus stress concentration reduction at the damaged area. The composite patches are bonded by the Adekit A-140 adhesive to repair an aluminum 2024-T3 plate. The geometric models for the study are a plate with a lateral crack and another plate with a crack emanating from a notch. The aim is to highlight the advantage of using high-modulus (HM) or high-strength (HS) carbon fibers to repair a plate with a variable stress concentration damaged area, and to assess the performance of different composites for variable crack lengths. The effects of crack size, the presence of a notch, the applied stress, and the use of a hybrid composite (combination of HM fibers and HS fibers) have been demonstrated.