Damage mechanism and evaluation of ultrasonic vibration nanolubricant grinding <scp>CFRP</scp> composites

Abstract As a key material in aerospace applications, carbon fiber reinforced polymer (CFRP) requires precision grinding to maintain the accuracy and integrity of assembly surfaces. However, machining damage remains a significant technical bottleneck that affects the service performance of CFRP components. To address this, ultrasonic vibration‐assisted minimum quantity lubrication (MQL) grinding with nanolubricants was developed. Despite this advancement, the formation and evolution of damage under the inherent random properties of grinding grains remain unclear. In this study, the instantaneous dynamic generation, conduction, and accumulation of grinding heat, along with its thermal effects, were examined. Additionally, 3D microscale three‐phase finite element numerical models were established to investigate the mechanisms of material removal and damage formation for different fiber orientation angles (FOAs) using single‐grain grinding. Grinding experiments were conducted to evaluate the damage distribution and quantitatively compare the effects of different ultrasonic vibration and nanolubricant combinations. The results indicate that the grinding damage mechanisms vary with FOA, complementing the debris generation mechanisms. Damage is primarily distributed along the grinding direction, with the lowest damage observed at 0° FOA and the highest at 45° FOA. The 2D ultrasonic‐assisted nanolubricant MQL with a 90° coupled vibration angle ( θ U ) provided the optimal damage reduction, achieving a maximum decrease of 27.56% compared with conventional grinding. In contrast, a 45° θ U showed excellent damage suppression only at 135° FOA, with a reduction of 40.38%. This article provides theoretical support for the damage suppression strategy in CFRP grinding. Highlights Instantaneous dynamic thermal generation of CFRP grinding was investigated. 3D mesoscopic CFRP grinding mechanical–thermal FEM models were established. Mechanisms of damage generation, evolution, and debris formation were revealed. Distribution and comparison of damages were quantitatively characterized.