Erosion mechanism and damage behavior of CFRP in plastic abrasive jet machining

Substrate damage brings great challenges to the efficient and nondestructive removal of aircraft skin coatings. Variable load erosion tests of unidirectional carbon fiber reinforced plastic along different fiber orientations were carried out. The effects of different fiber orientations on the erosion mechanism of CFRP are discussed separately. The matrix resin is squeezed and accumulated as platelets due to the erosion of the particles, and these platelets are removed due to repeated impacts of subsequent abrasives. The epoxy resin on the top layer of the laminate is penetrated by the particles with increased energy loss, and the fiber breakage is attributed to the direct impact of the particles on the carbon fiber. Fiber fractures are divided into micro-brittle fractures and macro-brittle fractures. Cracks are initiated by the concentrated stress of particle extrusion and propagate between the graphite crystallites, resulting in irregular micro-brittle fracture and fiber failure. Under the condition of macro-brittle fracture, the fiber will be debonded, flexural deformed, and even lost under the concentrated stress of particle extrusion. The purpose of this study is to provide a theoretical reference on the mechanism by which nondestructive and efficient removal of stealth coatings can be achieved on aircraft skins.