Development of Virtual Microscope Based on Renormalization Group Molecular Dyanamics and Its Application to Machining Process Observation

重整化基团分子动力学已被提出用于模拟从纳米到微米的各种尺度的物理现象。该方法既可以单独处理各种尺度，也可以组合处理各种尺度，从而可以在宏观尺度模拟结果的基础上重新进行局部缩放模拟，分析只发生在宏观尺度场的微观现象。然后用该方法分析了单晶硅在加工过程中如何形成缺陷。已经明确的机理是静/动相结合的，即局部不稳定的静应力状态引起由声波引起的动态重复拉/压作用引发的微剪切。这一事件随后在工具的浮雕表面下产生了晶体结构中材料性能减弱的非晶态区，并导致在那里形成微裂纹状缺陷，这也是由与穿过该区域的声波相关的动态拉伸应力造成的。

Renormalization group molecular dynamics has been proposed to simulate physical phenomena in various scales ranging from nanometer to micrometer. The method can handle various scales not only in separate manner but also in combined manner such that microscale phenomena which occur only in macroscale field can be analyzed by re-doing locally zoomed simulation based on results in macroscale simulation. The method is then used to analyze how defects can be formed in a monocrysytal silicon when it is machined. The mechanism which has been made clear is combined static/dynamic one such that a locally unstable static stress state causes micro shearing trigged by dyanamically repeated tensile/compressive action caused by acoustic wave. This event then creates amorphous zone with weakened material property in crystal structure under the relief face of a tool and leads to formation of a microcrack-like defect there, again by dynamic tensile stress associated with acoustic wave passing through the region.