Research on MD simulation for diamond tool cutting iron

In this paper, the molecular dynamics simulation method was used to establish the MD model for diamond cutting iron. The cutting process was simulated, and the change rules of temperature, cutting stress and radial distribution function with timestep were analysed. The results show that: As the cutting progresses, the temperature will increase gradually, the cutting stress fluctuates around 50,000 bars, and the wear mechanism of tool is analysed form a microscopic perspective; By adjusting the posture of the tool, the rake angle and the flank angle are changed, and the size of the thermostat layer and boundary layer are adjusted at the same time, which reduces the impact of non-Newton atoms on the workpiece; The change rules of temperature and cutting stress under different rake angle and flank angle conditions are analysed, and the minimum cutting stress is obtained when the rake angle is 15 degrees; By prefabricating a crack on the flank face, the change rule of the crack edge stress is studied. It is found that due to the occurrence of crack, the contact area between the tool and the workpiece is reduced, and there is obvious stress concentration at the edge of the crack.

本文采用分子动力学模拟方法，构建了金刚石切削铁的分子动力学（Molecular Dynamics, MD）模型，对切削过程进行了模拟，并分析了温度、切削应力与径向分布函数（Radial Distribution Function）随时间步长的变化规律。研究结果表明：随着切削进程推进，切削区温度逐渐升高，切削应力在50000巴附近波动，并从微观视角分析了刀具的磨损机制；通过调整刀具姿态，改变前角与后角，同时调控恒温层与边界层的尺寸，以此削弱非牛顿原子对工件的影响；分析了不同前角与后角条件下温度与切削应力的变化规律，得出当前角为15°时切削应力达到最小值；通过在刀具后刀面预制裂纹，研究了裂纹边缘应力的变化规律。研究发现，裂纹的存在减小了刀具与工件的接触面积，且在裂纹边缘处存在明显的应力集中现象。