Numerical Analysis of the Effects of Cutting Parameters on the Sub-Surface Damage in Machining of CFRPs

Abstract

Carbon Fiber Reinforced Plastics (CFRP) are widely used in the aerospace application. However, the machining induced sub-surface damage is critical to them. Because it would significantly reduce the reliability and the service life of the components. Particularly when the cutting angle is obtuse. The main purpose of this paper is to research the effect of the cutting parameters on the sub-surface damage in machining of CFRPs with obtuse cutting angle. And the numerical simulation is an effective method to study and observe the sub-surface damage under different cutting parameters. Despite some researches have been carried out on the effects of the cutting parameters on sub-surface damage through two-dimensional cutting models of CFRPs. The out-of-plane force also has influences on the change of the depth of the subsurface damage. And the generated cutting forces are unequal under different cutting widths during the cutting of the CFRPs. Therefore, the effects of the cutting width on the sub-surface damage still need to be studied. In this paper, a three-dimensional numerical model for the orthogonal cutting of CFRPs was developed based on the AbaqusTM. And the stress-strain relationship in the out-of-plane direction when machining CFRPs was considered in this model. Particularly, the mode I fracture in the transverse direction of the CFRPs was indicated by the damage factor of the tensile failure in the transverse direction to describe the sub-surface damage. The 135o cutting of the CFRPs under different cutting widths were simulated by this model, and the change of the depth of the sub-surface damage were analyzed. In addition, the simulation results were validated by experiments. The model provides an effective method for the prediction of the sub-surface damage, which is helpful for the optimization of the design of the tool.