Removal mechanisms and damage evolution in unidirectional Cf/SiC composites during 2D ultrasonic vibration-assisted grinding with a single diamond abrasive particle

Abstract

Carbon fiber-reinforced silicon carbide composites (C_f/SiC composites) offer high specific strength and high-temperature stability. However, their inherent hardness, brittleness, and anisotropy often cause severe defects during conventional grinding, such as fiber pullout and interfacial delamination. To address these challenges, a two-dimensional ultrasonic vibration-assisted grinding technique was applied to unidirectional C_f/SiC composites with a single diamond abrasive particle tool oriented transversely to the fiber direction. A three-dimensional finite element model based on a representative volume element was constructed to simulate the dynamic evolution of grinding forces and material damage during different phases of ultrasonic vibration. This model was used to systematically investigate how two-dimensional ultrasonic vibration influences the material removal mechanism and damage distribution. The results indicate that two-dimensional ultrasonic vibration significantly reduces the likelihood of localized brittle failure during material removal. It also suppresses fiber pullout and interfacial delamination, improves surface quality, and reduces the extent of subsurface cracks. However, when the maximum undeformed chip thickness is increased from 0.1 μm to 1 μm, ultrasonic vibration still reduces grinding forces and mitigates stress concentrations but fails to fully prevent large-scale delamination or collapse.