基于断裂力学的起重机焊接箱形梁疲劳寿命估算

Fracture mechanics based fatigue life estimation of crane welded box girder

随机载荷作用下的疲劳破坏是起重机焊接箱形梁的主要破坏形式之一。本文根据试验和研究成果,总结了桥门式起重机焊接箱形梁的各项疲劳参数取值。同时以等幅载荷疲劳裂纹稳定扩展阶段的计算公式为基础,针对起重机承受随机载荷的特点,利用均方根法对随机载荷进行等效处理,提出估算桥门式起重机焊接箱形梁的疲劳裂纹扩展寿命的方法。

The fatigue destruction caused by random load is one of the main destruction forms of the crane welded box girder. The values of the various fatigue parameters of welded box girders on overhead and gantry are summarized in this paper on the basis of previous test data and research achievements. The equivalent process- ing for random load is peffomaed with RMS method and a way to estimate the fatigue crack extension of the welded box girders is proposed based on calculating formulas for constant amplitude loading fatigue crack during stable extending period and the property of the random loads exerted on the cranes.