Abstract: As the main load-bearing component of a train, the fatigue strength of the body of a straddle monorail vehicle plays a crucial role in the safe operation of the train. In order to improve the accuracy of fatigue analysis of monorail vehicle body and simulate the fatigue damage of the vehicle body in the operation practice of monorail vehicle, the flexible treatment was carried out on the monorail vehicle body. The rigid flexible coupling dynamics model of a straddle type vehicle containing a flexible body was established. The virtual iteration method was used to apply white noise as the initial input excitation at the characteristic parts of the vehicle, and the measured acceleration of the straddle type monorail vehicle line was taken as the target signal. Then the simulation response spectrum of the vehicle model and the experimentally measured response spectrum were systematically identified and iteratively iterated to obtain the excitation spectrum at the connection position between the vehicle body and other components. Based on the virtual iterative excitation spectrum, the high-precision load spectrum was obtained. According to the linear fatigue damage theory, fatigue damage and life analysis were carried out on the body of the straddle type monorail vehicle, and an improvement plan for the vehicle body structure was proposed. The analysis results show that the fatigue simulation results have good consistency with the actual damage location of the vehicle body, which verifies the highprecision of the fatigue analysis results of the vehicle body load spectrum obtained by the virtual iteration method. The structural improvement plan has increased the service life of the vehicle body structure improvement position by 191%.

Key words: vehicle engineering; straddle monorail vehicle; vehicle body; fatigue analysis; virtual iteration method; load spectrum

摘要： 跨座式单轨车辆的车体作为列车的主要承载部件，其疲劳强度对列车的安全运行起着至关重要的作用。为提高单轨车体疲劳分析精度，模拟出单轨车辆运营实践中车体的疲劳损伤，对单轨车辆车体进行柔性化处理，建立包含柔性车体的跨座式车辆刚柔耦合动力学模型，采用虚拟迭代法，在车辆特征部位施加白噪声作为初始输入激励，以跨座式单轨车辆线路实测加速度为目标信号，对车辆模型仿真响应谱与试验实测响应谱进行系统识别与反复迭代，获取车体与车辆其他部件连接位置处激励谱。基于虚拟迭代激励谱获取高精度载荷谱，根据线性疲劳损伤理论对跨座式单轨车辆车体开展疲劳损伤与寿命分析，提出车体结构改进方案。分析结果显示：疲劳仿真结果与车体实际损伤位置具有良好的一致性，验证了采用虚拟迭代法获取的车体载荷谱开展的疲劳分析结果具有高精度；结构改进方案使车体结构改进位置处寿命提高了191%。

关键词: 车辆工程；跨座式单轨车辆；车体；疲劳分析；虚拟迭代法；载荷谱