单晶锗纳米切削过程应力场分布的分子动力学研究

为了进一步研究单晶锗的微纳米切削机理,首次采用分子动力学方法研究了材料原子的应力场分布以及不同刀具角度对应力分布的影响。采用近邻平均法计算了切削过程中不同时刻的hydrostatic应力和von Mises平均应力值。结果表明,在单晶锗的纳米切削过程中,最大平均应力集中于刀具尖端的亚表面区域,最大应力值为8.6Gpa。在切屑中也有很高的应力值,在4.2GPa左右。此外,刀具的角度也对应力场的分布有很大影响,绘制了不同刀具角度的切削力曲线。发现,刀具前角对切削力有显著影响。刀具采用负前角切削时切削力最大,而刀具后角对切削力没有影响,这与宏观切削理论相一致。

A molecular dynamics investigation of stress distribution into nanoscale scratching process of monocrystalline germanium

In order to further investigate the micro-nano scale monocrystalline germanium cutting mechanism, the molecular dynamics method was firstly used to simulate the stress field distribution of material atoms and the influence of different tool angles on stress distribution. The average stress value of hydrostatic and Von Mises at various times during the cutting process are calculated by nearest neighbor average method. The results show that during the nano-cutting process of monocrystalline germanium, the maximum average stress value is concentrated in the subsurface region of the tool tip, and the maximum stess is 8.6Gpa. There is also a high stress in the chip, which is around 4.2Gpa. In addition, the angle of the tool also has an influence on the distribution of the stress field. The cutting force curves of different tool angles are drawn. It is found that the tool rake angle has a significant influence on the cutting force. The cutting force is the largest when cutting with a negative rake angle, while the relief angle has no effect on the cutting force, which is consistent with the macro cutting theory.