Improvement of the repair method of the aircraft components made of polymer composite materials with operational damage

Abstract

The subject of study in this article is the repair method of the aircraft (A/C) components made of polymer composite materials (PCM) with operational damage. This article improves the repair method of the A/C PCM components with cracks and holes. Objectives: to improve the repair method of operational damage of the A/C PCM components by layer-by-layer removal of the defective area using a milling tool; propose dependencies to determine the serviceability period of the damaged area, considering the safety factor and geometric parameters of the defect. The following methods are used: analysis of existing and common repair methods of the A/C PCM components, mathematical approaches for their evaluation based on solving systems of equations. According to the analysis, the shortcomings of existing and common repair methods of the A/C PCM components with cracks and holes are identified. A proposal is made to improve the adhesive repair method of the A/C PCM components by using a milling tool with a curved cutting edge with a radius of curvature from 3 mm to 5 mm. The main stages of such repair are updated by filling the repair area with isotropic polymer paste. The dependencies of the geometrical parameters of layer-by-layer milling on the strength of the A/C PCM components are shown, considering the operating loads, calculated loads, and safety factors. The scientific novelties of the obtained results are as follows: the repair method of the A/C PCM components with operational damage using layer-by-layer milling with shaped radial mill to remove PCM layers in the defective area followed by filling the repair area with isotropic polymer paste is improved; the dependencies of geometric and strength parameters of the defective area of the A/C PCM components are established, which allow to easily determine the time of defect development before the destruction of the structure and the temporary period of serviceability of the A/C PCM components. The proposed improvement of the repair method will increase the period of operation of the A/C PCM components in general, which may be the next study.