基于Hopkinson压杆试验的小钎杆动态应力特性研究

Study on dynamic stress characteristics of small drill rod based on Hopkinson pressure rod experiment

在对锥体连接钎杆和整体钎杆2种典型小钎杆的应力传播模型进行理论分析的基础上,通过Hopkinson压杆试验系统对这2种钎杆杆体中部和钎头端部进行了动态应力测试。测试结果表明:2种钎杆杆体中部应力幅值基本没有差异,但锥体连接钎杆接头处具有30%的应力波反射,而整体钎杆没有;整体钎杆钎头端部最大入射应力波幅值的平均值比锥体连接钎杆的相应均值高出23%,使得整体钎杆的凿速比锥体连接钎杆的要高,但其损坏更快,预期寿命只有锥体连接钎杆寿命的18%,故整体钎杆更适用于软岩钻孔作业,而锥体连接钎杆更适用于硬岩钻孔作业,该试验研究为技术人员如何选用钎杆提供了理论指导。

Based on the theoretical analysis of the stress propagation models of two kinds of typical small drill rods,the conical connecting drill rod and the monolithic drill rod,the dynamic stress tests of the middle part and the end part of the two kinds of drill rods were carried out by using Hopkinson pressure rod experiment system.The experiment results show that the stress amplitudes of the middle part of the two kinds of drill rods are basically the same,but 30%of the stress exists at the joint of the conical connecting drill rod.The average value of the maximum incident stress wave amplitude at the end of the monolithic drill rod is 23%higher than the corresponding average value of the conical connecting drill rod.It makes the drilling speed of the monolithic drill rod higher and the damage faster than that of the conical connecting drill rod.The expected life of the monolithic drill rod is only 18%of the life of the conical connecting drill rod.So the monolithic drill rod is more suitable for drilling in soft rock,while the conical connecting drill rod is more suitable for drilling in hard rock,which provides a theoretical guidance for technicians to select the drill rod.