某型钻杆几何缩比及模态参数相似性分析

Geometric Scaling and Modal Parameter Similarity Analysis of a Drill Pipe

由于试验台的推力与空间限制,进行大型钻杆的动力学试验往往比较困难,采用数值仿真与缩比试验件试验相结合的方法,获取钻杆动力学特性是一个较好的解决方法。为了提高缩比钻杆动力学性能参数的准确性,以某大型钻杆为研究对象,研究钻杆的模态参数,探讨了有限元单元划分规模与结果收敛性之间的关系,确定合适的满足收敛性要求的有限元单元划分规模。研究结果表明:综合考虑计算精度、计算效率和缩比钻杆的加工性,该型钻杆的最佳缩比比例为25%;采用缩比25%的钻杆试验与数值仿真的模态频率进行对比,结果相对误差小于3.8%。所得结论可为钻杆数值仿真单元划分以及大型钻杆缩比试验件设计提供理论与技术参考。

Due to the restriction of thrust and space of the test bench,it is often difficult to carry out dynamic test on large drill pipes,so the combination of numerical simulation and scaled test piece test is a good solution to obtain the dynamic characteristics of drill pipes.In order to improve the dynamic performance parameter accuracy of the scaled drill pipe,a large drill pipe was taken as an example to study the modal parameters of the drill pipe,discuss the relationship between the finite element unit division scale and the convergence of the results,and determine the appropriate finite element unit division scale that meets the convergence requirements.The study results show that with comprehensive consideration to the calculation accuracy,computing efficiency and processability of scaled drill pipe,the optimal scaling ratio of the drill pipe is determined to be 25%.The comparison of modal frequency of 25%scaled drill pipe test and numerical simulation shows that the relative error is less than 3.8%.The conclusions provide theoretical and technical reference for the division of drill pipe numerical simulation units and the design of large drill pipe scaled test piece.