市域动车组转向架悬臂支架随机振动疲劳强度计算方法研究

Study on random vibration fatigue strength calculation method of urban EMU bogie cantilever bracket

市域动车组运行速度较高,轮轨振动激励高频成分较多,使得转向架上的悬臂支架在惯性振动载荷作用下振动剧烈,振动疲劳问题较为突出。针对此问题,文章提出了一种基于轴箱加速度的转向架非承载支架随机振动疲劳强度计算方法,用以评估转向架上主要承受惯性载荷的悬臂支架可靠性。该方法首先建立一系悬挂(考虑轴箱弹簧质量)的动力学特性模型,然后利用模态缩减方法建立转向架非承载支架应力对振动加速度的传递函数。基于振动加速度-应力传递函数及振动测试数据,可以快速分析支架应力响应及振动疲劳损伤。最后,开展线路试验和台架振动试验,对该方法进行验证。结果表明,该方法计算所得振动应力与试验结果基本一致。

The running speed of urban EMU is high,and there are many high-frequency components of wheel-rail vibration excitation,which makes the cantilever bracket on the bogie vibrate violently under the action of inertial vibration load.The vibration fatigue problem is more prominent.Aiming at this problem,this paper proposes a random vibration fatigue strength calculation method of bogie non-bearing bracket based on axle box acceleration,which is used to evaluate the reliability of cantilever bracket mainly subjected to inertial load on bogie.Firstly,the dynamic characteristic model of primary suspension(considering the mass of axle box spring)is established,and then the transfer function of the stress of bogie non-bearing bracket to the vibration acceleration is established by using the modal reduction method.Based on the vibration acceleration-stress transfer function and the axle box vibration test data,the stress response and vibration fatigue damage of the bracket can be quickly analyzed.Finally,the line test and bench vibration test are carried out to verify the method.The results show that the vibration stress calculated by the method is basically consistent with the test results.