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建立了车辆结构的刚柔耦合动力学模型,对比了刚性构架和柔性构架的振动响应,计算了构架的载荷谱;分析了应力谱转化方法,利用有限元方法与多项式拟合方法计算了构架的动应力谱;基于动应力谱与相关标准,运用线性累积损伤理论与疲劳裂纹扩展寿命Paris方程计算了构架的疲劳全寿命。计算结果表明:相比于多刚体车辆系统动力学模型,采用考虑构架柔性的车辆系统动力学模型计算的构架振动加速度响应在构架固有频率36.94~95.53Hz范围内的幅值较大,因此,构架的模态对振动响应的贡献显著;将载荷谱转化为应力谱的多项式拟合方法与瞬态分析方法相比较,应力误差最大值为1.16MPa,相对最大误差为3%,满足工程分析5%的计算精度要求;基于疲劳损伤理论计算的可靠度为95%的构架疲劳寿命为1.82×106 km;构架危险关注点裂纹由1mm扩展到2mm的寿命为1.76×106 km,满足中国高速列车车辆检修标准中制定的五级检修周期为1.2×106 km的要求。可见,构架模态参与下的动态应力谱计算方法与构架的疲劳全寿命预测方法可靠,有益于构架的动态设计与维修周期的制定。
The rigid-flexible coupled dynamic model of the vehicle structure is established. The vibration response of the rigid frame and the flexible frame is compared and the load spectrum of the frame is calculated. The method of transforming the stress spectrum is analyzed. The finite element method and the polynomial fitting method are used to calculate the stiffness of the frame Dynamic stress spectrum. Based on the dynamic stress spectrum and related standards, the fatigue life of the frame was calculated by using the linear cumulative damage theory and the Paris equation of fatigue crack growth life. The calculated results show that the vibration response of the frame calculated by the vehicle dynamics model considering the frame flexibility is larger than the natural frequency of the frame in the range of 36.94 ~ 95.53 Hz, compared with the dynamic model of multi-rigid-body vehicle system. Therefore, , The contribution of the modal to the vibration response is significant. Compared with the transient analysis method, the polynomial fitting method, which converts the load spectrum into the stress spectrum, has the maximum stress error of 1.16 MPa and the relative maximum error of 3% ; The fatigue life of the frame with 95% reliability calculated based on the theory of fatigue damage is 1.82 × 106 km; the life span of the frame with the focus of danger increasing from 1mm to 2mm is 1.76 × 106 km, which meets the requirements of China’s high-speed train vehicle overhaul The five-stage maintenance cycle stipulated in the standard is 1.2 × 106 km. It can be seen that the dynamic stress spectrum calculation method and the fatigue life prediction method under the framework modal participation are reliable and beneficial to the dynamic design and maintenance cycle of the framework.