基于使用工况的双梁起重机疲劳寿命分析OA

In relation to safety hazards such as fatigue failure,overload of power mechanisms,and failure of safety protection devices caused by long-term overwork of cranes beyond their working levels,a fatigue life analysis of double-girder cranes based on usage conditions was carried out.A finite element method was used to establish a model of the crane's bridge frame,and two typical fatigue working conditions,namely,no impact and bidirectional impact(including sudden lifting of the load while the trolley is braking),were set.The fatigue safety factors of the structure under each working condition were calculated and compared with the actual fatigue crack positions on site for verification.Under the bidirectional impact condition,the fatigue safety factor at the mid-span of the main girder decreased from 1.14 to 1.12,and at the end of the main girder,it dropped from 0.969 to 0.960.The fatigue critical point was located at the flange connection of the main end girder,which was highly consistent with the actual crack position on site.The research results show that illegal bidirectional or even tri-directional simultaneous operation can significantly aggravate the fatigue damage of the crane structure and pose a great safety hazard.The method proposed in this paper can effectively identify the fatigue weak points and provide a theoretical basis for optimization in the design stage and the formulation of operation norms.