动静组合加载下刀具破岩的力学模型

Mechanical Analysis on Rock Fragmentation under Combined Static and Dynamic Loading

基于初始弹性和动静荷分工的假设,将动静复合加载下坚硬完整的脆性岩石的破碎过程分为弹性、损伤和断裂3阶段,综合运用弹性力学、岩石力学、损伤力学和断裂力学进行分析。由集中力作用下弹性半空间的应力场和单元体的剪切破坏,得出了岩石损伤的裂纹源和其曲线扩展路径;选定Ⅰ型、Ⅱ型裂纹作为动载冲击作用下压剪裂纹的扩展模式。提出了以冲击能(次数)来定义损伤度的方法。以相邻破碎坑的侧向裂纹扩展贯通作为岩石破碎的终点。本力学模型可以用于动静复合加载破碎岩石的系统仿真、数值模拟和机具设计。

Based on the initial elastic and divisions of work by static and dynamic loads, the hard and intact brittle rock breaking process under static and dynamic loading is divided into 3 stages： elasticity, damage and fracture, which are ana- lyzed by comprehensive use of elastic mechanics, rock mechanics, damage mechanics and fracture mechanics. By the elas- tic half space stress field and shear failure of the rock unit under the concentrated force, the damage of rock crack source and its curve extension path are found; type I and type Ⅱ cracks are selected as press shear crack extension modes under dynamic load impact. Method to define the damage degree by impact energy （times） is put forward. The lateral crack prop- agation and coalescence of adjacent pit is defined as the end of rock breaking. This mechanical model can be applied in the system simulation, numerical simulation and machines design for rock breaking by combined static and dynamic loading.