FEM-Based Modeling of Drilling-Induced Delamination in Laminated FRP Composites

In fiber-reinforced plastics (FRP) laminate, different laminae are adhesively bonded to each other. The interfaces between plies are weak because these are resin rich; therefore, there is a low-resistance path for crack propagation. As a result of this, delamination is a frequent mode of failure in the FRP laminate. The drilling of laminated FRP is always associated with delamination damage; therefore, delamination-free drilling is a major concern for aerospace industries. Experimental investigations of drilling-induced delamination have been widely studied in the literature, whereas very few studies are available related to its modeling. In this paper, the effect of the chisel-edge length of drill-bit on push-out delamination was studied. Finite element modeling (FEM) approach was used to model interfaces of laminae, and it was further extended to model delamination in drilling of FRP laminate. Cohesive zone method (CZM) based on traction–separation law was used in FEM to model the interfaces of laminae. It was observed that load-carrying capacity of beam in double cantilever beam (DCB) test reduced by 50% for ‘1 mm’ initial crack length. Also, push-out delamination increased by around 10% with an increase in the chisel-edge length of drill bit from ‘0 mm’ to ‘0.35 mm.’ The FE models developed in this work were able to simulating delamination phenomenon with enough accuracy.