In aircraft construction and repair, sealants should be used at structural joints to ensure the sealing of pressurized cabin and structural fuel tank. The sealant of aviation scratch detector plays a decisive role in preventing and controlling the galvanic corrosion and crevice corrosion of aircraft structure. It can be used to fill and repair the riveting joints in aerodynamic sensitive areas to maintain and restore the streamline of aircraft and the smoothness of skin surface. But in the structural repair, inspection, the airframe skin of the lap, butt joint and other joint parts of the sealant removal. In the actual maintenance, mechanical tools such as scraper and scraper are often used, which may form surface scratches of varying degrees on the lower skin in the process of degumming. Most won't penetrate the fuselage's aluminum cladding, and some scratches may be deeper. Even the rigid plastic scraper will form scratches on the skin surface.

During flight, the pressurized load on the fuselage causes the skin of the fuselage to withstand toroidal stretching. Under this cyclic load, skin surface scratches will gradually form cracks in the skin lap joint. Aviation scratch detector because most of these cracks are under the sealant, and depending on how the sealant is removed, the cracks may be just at the edge of the connection, or hidden under the upper skin, not easy to check. Not many yet. The influence of surface scratches on mechanical parts is analyzed. Some evaluation methods and anti-scratch measures are given. However, for aircraft structures with relatively low strength reserve, the evaluation method and inspection method of surface scratch damage are of great significance to ensure their safety. Because of the special nature of supercharged fuselage skin damage caused by scratch line, scratch line damage has been studied abroad and is still being studied.

The research indicates that the repair techniques in the present structural repair manual may not be sufficient to ensure the structural integrity. In order to analyze the influence of scratch lines of different degrees on the supercharged skin structure of the fuselage, ANSYS software was used to calculate the detailed stress distribution of the structure, and local stress strain method was used to estimate the fatigue life under cyclic load.