基于四阶矩法车削颤振可靠性研究*

再生颤振是影响加工质量、加速刀具磨损、刀具破坏的主要原因。以车削加工为研究对象，针对具有不确定参数的车削加工颤振预测问题，研究车削加工系统结构动态特性参数具有随机特性的情况下颤振可靠性建模及求解问题。定义车削加工过程不出现颤振的概率为颤振可靠度，建立车削加工系统可靠性模型，研究四阶矩法求解可靠度的问题，提出利用颤振可靠性叶瓣图方法进行颤振预测。通过模态试验对一车床进行频响函数测试，采用四阶矩法计算获得了颤振可靠度，并与蒙特卡洛法获得的可靠度相比较。结果表明四阶矩法计算获得的可靠度与蒙特卡洛仿真结果一致性很好，但是四阶矩法计算精度高而且计算耗时远小于蒙特卡洛法。进行颤振可靠性切削试验，通过观察振纹和分析噪声功率谱识别颤振，对典型参数进行验证，试验结果与分析结果一致。

Chatter Reliability of Turning Processing System Based on Fourth Moment Method

Regenerative chatter is the main reason of affecting the machining quality, accelerating the tool wear and tool breakage. In order to solve the problem of turning chatter prediction with uncertain parameters, the reliability modeling and solution problem of the turning process system with uncertain parameters is studied. The Single degree of freedom dynamical model of turning processing system is built, and stochastic stability lobes diagram (SLD) model of turning chatter vibration is proposed. Monte Carlo method is adopted to solving the reliability. The case study is given:a CJ0625 lathe is measured to obtain the frequency response function(FRF), and the FRF diagram and SLD of the lathe with uncertainty parameters is shown. For 16 pairs of data of cutting width and spindle speed, the reliability are calculated according to the stochastic SLD and compared with the result of traditional SLD.