机床结构的模态参数识别与分析

本文在对机床结构模态参数识别和优化方法进行分析的基础上，对一台运转条件下的普通车床，模拟切削力进行了非接触式激振试验．用非线性优化方法，识别了机床结构的前１１个复模态参数．并在识别过程中引入了剩余柔度，采用了两种尺度法──ＤＦＰ与ＢＦＧＳ算法。综合了它们的优点．结果表明，此法数值计算稳定，收敛速度快．特别是对模态阶数较多、耦合较紧的情况，识别效果仍较好．

Identification and Analysis of Mechine Tool Structural Modal Parameters

On the basis of the modal analysis of the mechine tool structure and non-linear optimization,the experiment of a non-touch excited vibration which imitates real cutting force is made with acommon lath under its operating condition,and the first11complex modal parameters are identified.In the identification,the Rest Frequence Response Functions(RFRFS)are utilized and theaccuracy is enhanced. In the optimization,two existing efficient changing dimension bptimization methods-DFP and BFGS are both adopted and their advantages are used.The resultsshow that the method is steady in numerical iteration calculation and fast in convergence.Especislly,under the condition of the modal structure with high dimension and close coupling, the results of identification is still satisfying.