应用应力检测技术检验起重机的承载能力

Application of stress detection technology on testing the carrying capacity of crane

在成熟的设计及制造体系下,桥式起重机主梁整体刚度一般都能满足要求,但实际中重载高频使用的桥式起重机在主腹板受压区却频繁出现裂纹。因此,为进一步加强对起重机主要承载结构承载能力的检验,引入了采用应变片测量应力的方法。文中叙述了运用应力检测技术检验一台修复裂纹的起重机的承载能力。该起重机出现裂纹后进行两次加固修复,检验机构在修复后即对主梁主要受力区域进行应力测量,并对比前后两次应力数据,发现第二次加固修复后主梁承载能力反而进一步减弱。对于该现象在文中进行了推断分析。依据两次实测应力数据都显示了修复后的主梁主要受力区域强度不满足GB/T3811—2008《起重机设计规范》的要求。

Generally speaking,under the mature design and manufacturing system,the overall stiffness of the main girder of the bridge crane can meet the requirements,but in practice,cracks are easy to appear in the compression zone of the main web of the bridge crane used in heavy load and high frequency.Therefore,in order to further strengthen the inspection of the bearing capacity of the main bearing structures of cranes,the method of measuring stress through strain gauges is introduced.In this paper,it is described how to test the bearing capacity of a crane after crack repair by stress testing technology.After cracks appeared,the crane was reinforced and repaired twice,and the stress of the main stress area of the main girder was measured by the inspection mechanism after repair.Comparing the stress data before and after the second strengthening and repairing,it was found that the bearing capacity of the main beam decreases instead.This phenomenon is subject to analysis.The two measured stress data show that the strength of the main stress area of the repaired main girder can not meet requirements of GB/T 3811-2008 Code for Crane Design.