基于疲劳试验和断裂仿真的地铁障碍物检测装置寿命预测

LIFE PREDICTION OF METRO OBSTACLE DETECTOR BASED ON FATIGUE TEST AND FRACTURE SIMULATION

运用IEC61373标准的振动激励谱,将某地铁转向架障碍物检测装置作为研究对象。结合有限元法和台架振动试验对障碍物检测装置的随机振动疲劳强度进行了研究,并对铝横梁焊接接头疲劳薄弱点进行剩余寿命预测。基于频域法,结合Miner线性累积损伤理论,得到加速度激励下障碍物检测装置仿真寿命结果,将其与台架振动试验结果进行比较,验证了疲劳仿真分析的准确性。采用子模型边界技术将铝横梁分离出来,并对其疲劳薄弱点应力谱进行当量折算,在评估点插入初始裂纹后进行剩余寿命预测。结果表明,基于断裂力学评估带初始裂纹铝合金焊接接头的剩余寿命是合理的,为工程应用提供了一定的参考。

Using the vibration excitation spectrum of IEC61373, the subway bogie obstacle detector was taken as the research object. The random vibration fatigue strength of the obstacle detector was studied by combining the finite element method and bench vibration test, and the remaining life at the fatigue weak points of the aluminum beam welded joints was predicted. Based on the frequency domain method, combined with Miner’s linear accumulation damaging theory, the simulation life results of the obstacle detector under acceleration excitation were obtained, then compared with the bench vibration testing results to verify the accuracy of the fatigue simulation analysis. Moreover, the sub-model boundary technique was used to separate the aluminum beam, and the stress spectrum of the fatigue weak points was equivalently converted. At last, the remaining life was predicted after inserting the initial cracks at the evaluation points. The result indicated also that it is reasonable to evaluate the remaining life of aluminum alloy welded joints with initial cracks based on fracture mechanics, which provides the certain reference for engineering applications.