Investigation of the deformation and thrust forces generated during the drilling of GFRP composites

Abstract

Glass fiber-reinforced polymer (GFRP) composites are widely used in industry due to their advantageous properties, such as a high strength-to-weight ratio. However, during the preparatory processes for bolted or riveted joints, drilling operations often lead to delamination damage, which adversely affects the mechanical performance and reliability of these materials. In this study, the effects of different cutting speeds and feeds on thrust force and delamination damage during the drilling of GFRP composites were investigated. The maximum thrust forces generated during the hole drilling process were measured, and post-drilling deformations were examined. Mathematical models were developed using the response surface method (RSM) to predict thrust force and delamination under various cutting conditions determined by the selected drill geometry. The results of the analysis of variance (ANOVA) showed that the developed models were statistically significant with a confidence level of over 90%. It was found that feed is the dominant parameter influencing thrust force, whereas cutting speed plays a primary role in determining the extent of delamination. The results provide valuable insights for establishing optimum cutting conditions aimed at minimizing drilling damage in GFRP composite machining.