Effect of backup plate in drilling of composite laminates, analytical and experimental approaches

Abstract

Delamination is the most severe damage in drilling of composite laminates. Using the backup plate is an appropriate method to control drilling induced delamination. In this paper, an analytical model is applied to determine the critical thrust force and the feed rate for drilling of composite laminates with backup plate. To achieve this aim, the classical laminate plate theory (CLPT), the linear elastic fracture mechanic (LEFM) and the oblique cutting model are used. In analytical models, two separate distributed loads have been exerted by cutting and chisel edges. Based on the model results, the effect of the drill diameter, the chisel edge size, and the backup plate size, on the critical thrust force and the feed rate are investigated. Experimental tests are carried out to prove the analytical model.