网架结构疲劳及其疲劳寿命计算

Fatigue of Space Trusses and Its Fatigue Life Calculation

本文首次在应用自制荷重自动记录仪的基础上，总结出二十多种车间吊车随机荷载的统计分布规律。并采用了Ｘ２拟合优度检验法和偏度、峰度检验法对它们进行了假设检验。在动荷载的自动记录中发现了一次起吊可引起多次循环加、卸载的动力作用，应在疲劳寿命计算中加以考虑。本文在大量实验的基础上提出了对焊接节点采用断裂力学的方法和对螺栓球节点应用累积损伤理论估算它们疲劳寿命的计算方法。

In this paper the regularity of statistical distribution of random crane loads of more than 20 workshops has been concluded by the automatic load recorder made in the laboratory of Northern Jiaotong University. Furthermore the correctness of normal distribution has been proved by the hypothesis testing of X2 goodness of-fit testing and the skewness-kurtosis testing. It has been found by the automatic load recorder that the dynamic effect caused by crane load during lifting may produce many cycles of loading and unloading repetitions. Finally, the methods for calculating fatigue life based on fracture mechanics for welded node and cumulative damage theory for bolted sphere node respectively have been presented.