响应耦合子结构法的轴类工件频响函数预测

Prediction of Frequency Response Function of Shaft Workpiece Based on Response Coupling Substructure Method

轴类工件切屑过程中,容易产生颤振影响加工稳定性,快速计算工件频响函数,便能为防止颤振提供依据。由于车削加工工件频繁更换,针对以往测量工件频响函数往往采用锤击法需要重复测量等问题,提出一种改进的子结构划分方法。该方法将主轴-卡盘-工件系统划分为主轴-卡盘-夹持部分、工件悬伸部分,使用子结构响应耦合法(RCSA)、有限差分法、Timoshenko梁模型求取轴类工件任意截面频响函数,并利用该方法探究了尾座对工件频响函数的影响。此划分方法避免了结合面的参数辨识,能够快速方便预测工件任意截面频响函数,与仿真所得频响函数进行对比,预测结果与仿真结果对比误差在5.38%以内,验证了该预测模型的有效性。

In the chip cutting process of shaft workpiece,it is easy to produce chatter,which affects the machining stability.Fast calculation of workpiece frequency response function can provide a basis for preventing chatter.Due to the frequent replacement of turning workpieces,an improved substructure division method is proposed to solve the problem that hammering method is often used to measure the frequency response function of workpieces in the past.In this method,the spindle-chuck-workpiece system is divided into spindle-chuck-clamping part and workpiece suspension part.Based on substructure response coupling method(RCSA)and finite difference method,Timoshenko beam model is used to calculate the frequency response function of any section of shaft workpiece.The influence of tailstock on workpiece is explored by this method.This partition method avoids the parameter identification of the joint surface,and can quickly and conveniently predict the frequency response function of any section of the workpiece.Compared with the simulated frequency response function,the prediction error is less than 5.38%,which verifies the ef-fectiveness of the prediction model.