Abstract: When rigid and rectangular indenter was pressed on the surface of the two-dimensional elastic substrate, a flat indentation and a singular stress fields arise, which will cause surface of the substrate to fracture. As a typical application of the flat indentation, the rack breaking mechanism for drilling bit with periodic-arrayed flat-ended teeth has been investigated. The mixed mode stress intensity factor(I-type and II-type) for periodic cylindrical indentation is derived. The upper and lower bounds for boundary critical cracking angle and the upper and lower bounds for critical loads are derived. The rock breaking behaviors has been formulized. 

Key words: Rock cutting, Flat indentation, Stress intensity factor, Fracture mechanics, Contact mechanics

摘要： 当二维刚性平端压头作用在弹性体的表面时，形成一个平面压痕，并在压痕的边界诱生出裂纹型的奇异应力场，该应力场将使弹性体的表面产生断裂型开裂。柱壳周期阵列平齿取芯钻作为典型的平面压痕模型在工程中的应用，利用平面压痕断裂力学模型，分析了该取芯钻的断裂型破岩机理。导出了柱壳周期阵列平面压痕Ｉ－型和ＩＩ－型应力强度因子，给出了周期阵列压痕临界开裂角的上界与下界，以及临界破岩载荷的上界与下界，建立了取芯钻断裂型破岩行为的定量分析方法。

关键词: 岩石切割 , 平面压痕 , 应力强度因子 , 断裂力学 , 接触力学