本文使用準穩態分子靜力學方法針對具有缺陷存在的矽工件進行奈米級正交切削模擬，分析其切削力、切屑形狀、等效應力及等效應變的模擬結果。單晶矽在長晶時內部仍會產生許多點缺陷，經過熱能效應產生聚結擴散可能形成微缺陷，這些點缺陷因聚集的方式及形狀不同而有不同名稱，故本文將一個、兩個孔洞及成排空位原子設定在單晶矽材料當中，以具有後斜角15度及間隙角10度的單晶鑽石刀具對工件進行切削模擬，並與無缺陷結晶的材料作出分析比較。
本文所使用的三維準穩態奈米靜力學奈米切削模式，所撰寫的切削主程式使用編碼的方式，不只可對無缺陷晶格的工件作出模擬，亦能處理內部產生缺陷的工件切削，即使是出現不同位置缺陷時，也可依編號的方式，一一對各種不同邊界條件的參數來進行切削探討。當刀具與工件做動時，因為彼此間勢能的影響造成原子的位移，計算每個原子的運動軌跡直接求解每個原子移動一小段距離後，應用力平衡之概念，並以最佳化的方法來求解力平衡方程式求出新的運動位置，推算出切削時切屑的形成。在等效應力及等效應變方面，利用有限元素法中的形狀函數概念求出矽工件中間斷面之等效應變，再由塑流應力-應變曲線(flow stress-strain)的關係式得到等效應力的數值，進而得到被切削矽工間斷面的等效應變與等效應力的分佈趨勢。

This paper uses quasi-steady molecular statics method to carry out simulation of nanoscale orthogonal cutting of silicon workpiece with defects existed, and analyzes the simulation results of its cutting force, chip shape, equivalent stress and equivalent strain. During crystal growth period, single-crystal silicon still has many point defects caused inside. The agglomeration and diffusion caused after thermal energy effect may form micro defects. Due to different ways and different shapes of agglomeration, these point defects have different names. Therefore, this paper puts one hole, two holes and a row of empty atoms in a single-crystal material, and uses a single-crystal diamond cutting tool with rake angle 15° and clearance angle 10° to carry out simulated cutting of workpiece. After that, the paper analyzes and compares this simulated cutting with that of perfect crystal material.
For the three-dimensional quasi-steady molecular statics nanocutting model used by this paper, the main cutting formula written uses the way of coding. It not only can simulate the workpiece with defect-free lattice, but also can perform cutting of workpiece with defects produced inside. Even though defects appear at different positions, cutting can be explored towards the parameters of different boundary conditions according to the coding way. When cutting tool starts to have action with the workpiece, displacement of atoms is caused by the potential energy of each other. After the motion trajectory of each atom is calculated to directly find the movement of each atom for a small distance, the concept of force balance and optimization method are applied to acquire a force balance equation so as to find the new motion position. It is inferred that chips are formed during cutting. As to equivalent stress and equivalent strain, the concept of shape function in finite element method is adopted to obtain the equivalent strain on the middle section of silicon workpiece. From the flow stress-strain relational equation, the numerical value of equivalent stress can be obtained. Furthermore, the distribution trend of equivalent strain and equivalent stress on the middle section of the silicon workpiece being cut can be acquired.

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