基于频域法的转向架构架疲劳寿命研究

STUDY ON FATIGUE LIFE IN FREQUENCY DOMAIN FOR BOGIE FRAME

传统的转向架构架疲劳设计大多采用常幅加载,与构架实际运行中所受的随机激励明显不符,从而导致构架整体疲劳强度过量设计和局部结构抗疲劳不足的问题。首先利用逆傅里叶变换法对某随机过程信号进行了时域和频域数值模拟转换,并与该信号的解析值进行比较,验证了所建立的载荷历程正确性和合理性。然后基于逆傅里叶变换法和三次样条差值法,分别给出了轨道垂向不平顺和水平不平顺的位移、速度、加速度功率谱数值模拟方法。最后,以某高速转向架为例,对其进行了考虑车体以及构架各轮对之间相互作用的多点多轴随机振动分析,真实模拟了构架运行工况,并对构架结构疲劳薄弱位置进行了预测。研究结果表明,频域疲劳计算方法能较好地预测振动疲劳,为构架的抗疲劳设计和优化提供了一种新的方法。

Traditional bogie frame fatigue design uses the amplitude loads, which is significantly not inconsistent with random excitation suffered on the frame in actual operation. This method often leads to excessive fatigue strength of the overall frame and the anti-fatigue design in local structure insufficient. Firstly, the inverse Fourier transform was used to transform the stochastic process between time domain and frequency domain, and the correctness and feasibility of load history which proposed is verified by comparative analysis. Then, based on the inverse Fourier transform method and cubic spline differential method, rail vertical irregularity and longitudinal irregularity in displacement, velocity and acceleration power spectrum were given, respectively. Finally, the multi-point and multi-axis random vibration analysis of the bogie frame was processed, the real operating conditions of the structure were simulated, and the weak fatigue position of the structure was predicted. The results shows that the fatigue life calculation of the frequency-domain can be good used to predict the vibration fatigue, and provide an effective method for anti-fatigue design of bogie frame.