动力总成悬置系统频率和解耦率的稳健性分析方法

It is unavoidable that the mount stiffness of a powertrain mounting system (PMS) is uncertain during manufacturing, installation and vehicle operation. To disclose the variation characteristics of frequency and decoupling ratio of a PMS, interval number is used to describe the uncertainty of the stiffness given the variation range of the mount stiffness, and the probability density function of the stiffness need not to be known. The six-degree-of-freedom vibration analysis model of a PMS is presented. Based on the Taylor’s series expansion and interval truncation method, an effective interval analysis method for estimating the variation ranges of the frequency and decoupling ratio is presented. The computational method of interval reliability is given to characterize the robustness of frequency and decoupling ratio. Computational results show that the presented interval analysis method could estimate the intervals of the frequency and decoupling ratio with satisfactory accuracy. And the interval reliabilities of frequency in the pitch direction and the interval reliabilities of decoupling ratios in the vertical and pitch directions are low. Thus the mount stiffness parameters need to be optimized in order to increase the robustness of frequency and decoupling ratio of the PMS.