Investigation of buckling of laminated composites repaired by resin injection using acoustic emission and cohesive zone simulation method

Abstract

Due to their low weight ratio, excellent damping behavior, and high strength characteristics, composite materials are widely used in different industries, including aerospace. Despite the excellent mechanical behavior, most of these materials suffer from damages such as delamination when undergoing low-energy impacts. In the present study, repairing the composite structures using the resin injection into the damaged zone is analyzed. In some samples, initial delamination is included during the manufacturing process using the Teflon film, while the other samples are left to be intact. Furthermore, the delamination inside the composite sample has been simulated using the cohesive zone method (CZM) using ABAQUS software. The samples with delamination were repaired with the resin injection method. Finally, all samples underwent the buckling test, and the buckling process of the samples was monitored using the acoustic emission method. The amounts of damage mechanisms of delamination growth, fiber breakage, and matrix cracking were calculated using the wavelet method. The results show a good agreement between the experimental results with both the finite element method (FEM) and the acoustic emission results. Besides, the restoration percentages of compressive strength in samples repaired with stacking sequence [0]8, [90]8, and [0/90]8 were 88%, 87%, and 91.7%, respectively.