Research On Crack Propagation And Optimization Of Casting Crane Structural Based On XFEM

Casting crane is a high frequency heavy duty equipment for lifting molten metal in metallurgical workshop.Its efficient and safe operation in design life cycle is an important factor affecting metallurgical production.The common structure of casting crane often has great hidden danger because of fatigue crack propagation.In order to solve these problems,this paper uses extended finite element method to study the crack propagation in the key parts of the bridge structure of casting crane.Based on this,optimization analysis and research are carried out on the main girder of casting crane bridge to prevent cracks from appearing prematurely.According to the real structure of a ladle crane,set up by using APDL language casting crane bridge whole car model,analysis of the structure under the condition of stress and strain of the whole situation,and the finite element statics results with test results,this paper compares and analyzes the correctness and rationality of the model is proved,speculated that crane causes of crack.The stress analyzed in the above working conditions was checked to meet the strength conditions.Crack propagation simulation was carried out for about 100 mm crack at the end of casting crane.According to the field investigation data,a microcrack was prefabricated at the maximum stress position at the end of the box girder,and the stress intensity factors under different crack lengths were simulated by extended finite element method.The relationship curve between the crack propagation length and the number of load cycles was drawn,which provided a basis for the safety evaluation of the crane.Due to the unreasonable structure of the crane end,the crack takes the lead and affects the working efficiency of the crane.In this paper,hot spot stress method is used to check the fatigue strength of end stress and determine the cause of crack.The function of hot spot stress at the end is constructed.Based on the optimization theory,the section of box beam and related parameters at the end are selected as independent variables for optimization analysis.Finally,the hot spot stress of the optimized box beam structure meets the fatigue strength and its mass is reduced.