基于响应耦合子结构法的机床动力学特性分析

Dynamic Characteristics Analysis of Machine Tools Based on Method of Receptance Coupling Substructure Analysis

采用基于响应耦合子结构法(RCSA法)研究机床整个工作空间内刀具中心点(tool center point,TCP)的频率响应函数。首先,建立机床主轴和床身子结构的动力学模型,推导出子结构结合部的频率响应函数;再根据子结构结合部的变形协调关系及受力平衡条件,由RCSA法获得机床TCP的动力学特性;并以立式机床VDF850为算例,采用RCSA法计算主轴位于Z轴顶部位置时TCP的动柔度幅值频率响应,并与整机有限元法结果相比较。结果表明:两种方法的动柔度幅频响应变化趋势基本一致,验证了RCSA法的可行性;且RCSA法避免了整机有限元法的大规模矩阵特征方程求解,计算效率有所提高。

Amethod based on response coupling substructure analysis(RCSA)was employed to study the frequency response function of tool center point(TCP)in the whole workspace of machine tools.Firstly,the dynamic models of the spindle and the bed substructure of the machine tool were established respectively,and the frequency response function of the joint of the substructure was deduced.Then,the dynamic characteristics of machine tool TCP were obtained by RCSA method according to the deformation coordination relationship and force balance condition of substructure joint.Taking VDF850 vertical machine tool as an example,RCSA method was used to calculate the dynamic flexibility amplitude and frequency response of TCP when spindle was at the top of Z axis,and the results were compared with those of finite element method of the whole machine.The results show that the dynamic flexibility amplitude-frequency response trends of the two methods are basically the same,which verifies the feasibility of RCSA method.Moreover,RCSA method avoids solving large-scale matrix eigenvalue equation of the finite element method of the whole machine,and improves the computational efficiency.