新型锥形PDC齿犁削破岩理论研究

Theoretical research on the ploughing rock breaking properties of new conical PDC cutter

目前关于锥形PDC齿的研究主要集中于数值模拟、现场及室内试验,而关于其切削力学特性的理论分析未见相关报道。通过数值模拟阐述了锥形PDC齿拉伸剪切破岩机理,以及切削载荷分布特性;根据能量平衡原理,推导了锥形PDC齿切削载荷理论公式。结果表明,相比于常规PDC齿,锥形PDC齿破岩过程更加稳定,其切削载荷受岩石性质、齿的形状参数、切削深度以及切削角度的影响,且切削载荷随着锥顶半径、切削角度以及吃入岩石深度的增加而增加。研究成果可为锥形PDC齿及钻头的设计提供理论支撑。

The researches on the conical PDC cutter are now focused on numerical simulation,field and laboratory tests,the theoretical analysis on its mechanical properties has not been reported.Therefore,the tensile shear rock breaking mechanism and cutting load distribution characteristics of the conical PDC cutter are described by numerical simulation,the theoretical formula of the cutting load is derived according to the energy balance principle.Results show that comparing with the conventional cylindrical PDC cutter,the rock breaking process of conical PDC cutter is more stable,the cutting load is influenced by the rock properties,the parameters of cutter structure,the cutting depth,and the cutting angle;the cutting load of conical PDC cutter increases with the increase of cone top radius,cutting angle and cutting depth.The research results can provide theoretical support for the design of conical PDC cutter and the PDC bit.