Mechanics of fibre deformation and fracture in vibration-assisted cutting of unidirectional fibre-reinforced polymer composites

Abstract

Fibre orientation significantly affects the surface integrity of the machined fibre-reinforced polymer (FRP) composites. Crushing or bending-dominated fibre fracture in the machining of FRPs is governed by fibre orientation relative to the cutting direction. This paper revealed the mechanics behind such phenomena and developed a reliable predictive model for cutting FRPs. The analysis integrated the effect of the whole fibre orientation range from 0° to 180°. Both traditional cutting and elliptic vibration-assisted (EVA) cutting of unidirectional FRPs were analysed by integrating microstructure-based and equivalent homogeneous deformation zones. A systematic experiment was also carried out. A comprehensive comparison of the mechanics predictions with the experiments shows that the model has captured the major material removal mechanisms and can be used to predict fibre deformation, fibre–matrix debonding, fibre fracture, subsurface damage and cutting forces in both traditional and vibration-assisted cutting. It was identified that fibre orientation affects subsurface damage and cutting forces significantly, and that EVA cutting can minimise the orientation effect. There is a critical fibre orientation at which subsurface damage and cutting force in feed direction would reach their worst situations.