Predictive modelling and experimental validation of cutting-force prediction for axial ultrasonic vibratory end-face grinding of 2D-SiCf/SiC ceramic composites

SiC/SiC ceramic matrix composite is a high-temperature thermal structural fibre-reinforced material with SiC as the matrix and SiC fibre as the reinforcement. It is known for its high specific strength, specific modulus, corrosion resistance, wear resistance, fracture toughness, and thermal stability. It has become the most reliable material for the thermal components of aircraft engines. Axial ultrasonic vibratory face grinding is an efficient method for machining hard and brittle materials. In this study, the structural properties of two-dimensional SiC/SiC ceramic matrix composites were analysed by the representative volume element modelling. Subsequently, they were estimated using the stiffness averaging method, and the results were utilised for force analysis. The axial grinding force model for the rotary ultrasonic end milling (RUG) of SiCf/SiC composites was developed by considering the cutting trajectory and energy conservation theorem based on the indentation fracture theory of material removal mechanism. The model was verified through an ultrasonic vibration-assisted grinding experiment. The experimental results were consistent with the theoretical model, with the maximum model error being less than 15% and the average error being 7.39%. The relationship between the grinding force, surface roughness, and machining parameters (including spindle speed, feed rate, and ultrasonic amplitude size) was investigated to provide a theoretical basis for the optimisation of process parameters in the experimental study of machining surface quality.