Study on the performance of CFRP stepped-lap repair for aerospace

Abstract In this paper, a novel progressive damage model of stepped-lap repair structure is established. The ultimate load of CFRP stepped-lap repair structure under uniaxial tension is studied. The accuracy of the simulation results is verified by experiments. Then, the influence of the number of different steps is systematically studied for the first time. The progressive damage analysis of the repaired structure is carried out. Finally, the influence of the slope on the repair is discussed. The results show that the failure load of the four-step repair is the highest. The damage of the adhesive layer starts from the edge of the step and extends to the periphery until failure. The stress in the repair structure is mainly distributed in the 0° ply. The stress in the parent plate is mainly concentrated at the edge of the repair area, while the stress in the patch is generally distributed at the corresponding position of the defect area. The four-step repair with a slope of 1:30 has the strongest tensile strength and the highest failure load. The purpose of this paper is to explore the repair and strength analysis of aerospace composite materials and to provide a reference for the maintenance and reliability evaluation of aerospace composite materials.