门座式起重机小拉杆提前损坏的原因探讨

Previous damage cause of small tension bar for portal crane

本文论述了门座起重机小拉杆的损坏是由于在起重机变幅过程中,小拉杆承受较大的附加应力所致。平衡梁与臂架之间的安装误差产生应力波动,循环应力性质和小拉杆本身的焊接缺陷及附加应力形成裂纹以及扩展直至构件断裂。给出了附加应力的计算方法。该方法对传统的门机计算是一个较重要的改进。

This paper discussed the wreck of the small pole of portal crane is because the small pole supported greater add working stress in range- changing process. And more, the fixing error between the balance girder and the arm bracket make the small pole support more stress, and also enlarge the stress. Cycle stress and the weld lacuna make the crack beginning and growing and make the pole destruction in the last. The paper gives the calculation methods of add - ons stress. The method improves the conventional calculation method.