基于动态服役环境轮轨激振下的高速动车组齿轮箱体裂纹产生机理研究

Gearbox housing crack under dynamic service environments has been a serious threat to the operation safety of high-speed train，so the crack generation mechanism urgently needs to be explored. This project takes CRH3 as the research object，the crack generation mechanism of gearbox housing under wheel/rail excitation of dynamic service environments are investigated in the method of combining dynamics and fatigue strength theory. Firstly，the vibration characteristics of dynamic response evolution rule of gearbox housing are carried out on the ground of tracking tests along the railway lines. Then，the nonlinear resonance mechanism of gearbox housing is explored by constructed dynamic model of the transmission system. Moreover，constructing rigid-flexible coupling dynamic simulation models of high-speed EMU, which takes service environments into consideration. Some characteristics such as load spectrum，acceleration，transmission characteristics of frequency vibration，the evolvement rule of stress-strain for gearbox housing under wheel/rail excitation are revealed by means of dynamics simulation analysis. Lastly，the dynamics performance and vibration fatigue strength retrogression performance of gearbox housing being studied through high-frequency excitation test of wheel/rail，combining equivalent damage theory and crack generation mechanism，the prediction methods and the models of crack generation life-span are put forward on the basis of crack generation mechanism of gearbox housing on high-speed EMU under wheel/rail excitation of dynamic service environments. The anticipated research results will exert greatly theoretical significance and engineering practice value to optimization design and life-span predication of gearbox housing as well as ensuring the operation safety of high-speed EMU.

动态服役环境下齿轮箱体开裂问题已严重威胁高速列车运行安全，因此迫切需要揭示其产生机理。本项目以CRH3型动车为研究对象，基于动态服役环境轮轨激振条件，运用动力学与疲劳强度理论相结合的方法，研究齿轮箱体裂纹产生机理。首先，基于线路跟踪试验研究齿轮箱体振动特性动态响应演化规律；其次，建立齿轮箱传动系统动力学模型，研究其非线性共振响应机理；接着，构建考虑服役环境下整车刚柔耦合动力学仿真模型，通过动力学仿真揭示轮轨激振下箱体的载荷谱、加速度和频率振动传递特性及应力-应变演化规律；然后，基于轮轨高频激振试验，研究箱体动力学性能和振动疲劳强度衰减特性；最后，基于上述研究，结合等损伤理论和裂纹萌生机理，研究齿轮箱体在动态服役环境轮轨激振工况下裂纹产生机理，提出箱体振动疲劳寿命预测方法和裂纹萌生寿命模型。预期研究成果对优化齿轮箱体设计、预测箱体寿命、确保行车安全具有重要的理论意义和工程实用价值。

高速动车组齿轮箱箱体是动力驱动传动的关键部件，其服役性能的安全稳定性是影响高速动车组安全的关键因素，而箱体开裂势必严重威胁高速动车组运行安全，因此探究服役环境下动车组齿轮箱体裂纹产生机理对高速动车组齿轮箱系统的安全服役具有重要理论意义和工程实用价值。本项目基于动态服役环境轮轨激振条件下，针对高速动车组齿轮箱体服役过程中生产裂纹影响运行安全性问题，通过线路跟踪试验、动力学仿真及台架试验等技术手段并结合疲劳损伤理论研究其裂纹产生机理，取得了较为丰硕的研究成果。首先，对齿轮箱传动系统产生的故障进行比较系统的调研，对产生故障的齿轮箱进行分解检测，提取故障部位存在缺陷现象并分析其产生的原因；提出了对动车组齿轮箱提出科学的服役跟踪测试方案。其次，完成了对CRH3型高速列车齿轮箱体在哈大线服役跟踪振动特性试验，发现B型原结构齿轮箱存在580Hz模态主频，与线路激扰主频存在交集，是导致列车运营时出现箱体局部共振现象是箱体产生振动疲劳损伤裂纹的主因；通过建立考虑内、外部激励下的齿轮箱传动系统动力学模型，分析了箱体产生裂纹的原因。然后，建立考虑动态服役环境轮轨激振下整车精细化刚柔耦合动力学模型，进行各种工况下的齿轮箱体动力学仿真分析，明确齿轮箱箱体的振动加速度及应力响应演化规律。基于小滚轮高频激励台架试验，通过扫频分析，探究了高速列车齿轮箱箱体振动特性和疲劳损伤影响因子。最后，结合相关标准、线路实测试验，评估齿轮箱箱体在各种载荷工况下的疲劳失效，分析出高速列车齿轮箱箱体疲劳损伤、寿命及裂纹产生机理。本项目研究所取成果丰富了高速列车齿轮箱箱体振动特性及高频振动疲劳损伤导致裂纹的机理，为避免或抑制齿轮箱在服役线路上产生振动疲劳损伤提供了重要的参考价值。