Elastic-plastic Fracture Parameter Simulation And Safety Evaluation Of Crane Box Beam Structure Containing Defects

Crane as material handling, loading and unloading machinery products, the demand is increasing. It brought material wealth for human beings, at the same time, also brought the potential risks, safety accidents caused by structural fracture is one of the risks. The quantity of serving crane increasing, especially the elderly and the serving overage quantity increases gradually, the potential safety risk is growing, production safety situation is increasingly grim, forcing people to focus on the performance of the state during crane serving, especially the safety status, the crane safety evaluation is becoming more and more urgent and importantThe article treated the crane girder structure as the research object, from solving the control parameters of elastic-plastic fracture on crane box beam structure and crack extension to study, to explore suitable calculation method for J integral -the key control parameters of elastic-plastic fracture on crane structure, and crack steady extension conditions based on the elastic-plastic fracture, to preliminary establish elastic-plastic fracture safety evaluation process suitable for the bridge (the door) crane structure safety evaluation and finite element simulation method of the key control parameters. The main content of the paper includes:(1) The destruction characteristics of the crane box beam structure and its engineering treatment method. Summing up out of the box girder structure serving type crack defects and extension mechanism of law; Combined with the bridge (the door) crane metal structure work background, summarizes the performance characteristics of welded box girder structure, the existence question and its size parameters of the defects of engineering characterization rules.(2) Do 36 t crane box beam structure statics analysis and calculate the loads, and through the finite element software simulation of the whole machine statics, getting strength and rigidity and stress distribution of the machine; Two-dimensional flat J integral numerical calculation method and examples; Based on the statics analysis of box beam structure, to join the crack, using the finite element software ABAQUS to simulation, and calculated the crack tip J integral value; deducing failure curve FAC according to the J control crack propagation failure; Using the software on the basis of the principle of yield directly solves ultimate load of through crack on the box girder, and get the calculation formula of the through crack plate load ratio Sr; on the basis of simulation by the crack tip J integral value known as well as the failure assessment diagram and calculation formula of the Sr,do safety evaluation of crack in structures.(3) Combined with fracture criterion, using extended finite element method(XFEM) to simulating crack extension. Giving the extension finite element analysis specific process of the box beam structure containing crack with ABAQUS software, getting the fracture parameters of structure containing crack and the extension direction and state of crack structure.