Research On Statics And Crack Propagation Of Main Girder Of Metallurgical Crane

Crane failure and fracture accidents caused by crack propagation of main girder of crane's key structural components usually cause heavy casualties and heavy losses of state and company property.In all kinds of crane accidents,metallurgical crane ranks first,so the crack research of the main girder of the key structure of metallurgical crane is of great significance to the safety of employees and the reduction of property losses.In the study of cracks in the main girder of the key structure of metallurgical crane,finite element static analysis can help designers better understand the distribution of stress and stress and deformation of the main girder of the key structure of metallurgical crane under load.The causes of crack initiation are found out from the point of view of welding defects in main girder manufacturing.Further research on crack propagation is carried out.Prefabrication of cracks at crack-prone locations simulates the path of crack growth and evaluates the time period required for crack propagation to critical size.The main work in the whole research content is as follows:(1)SolidWorks software is selected to complete the three-dimensional modeling of the main girder,end girder and auxiliary girder of metallurgical crane,and complete the overall assembly of the bridge structure of metallurgical crane.The finite element model of crane bridge and girder is established correctly,and the element type,mesh division,load category and working condition are selected.(2)Based on ABAQUS software static analysis module,the deformation and stress intensity distribution of the overall structure of the metallurgical crane are analyzed,and the key research object is determined as the main beam structure.The finite element model of the prefabricated upper arch of the main girder of the metallurgical crane and the static results of the finite element model corrected by the prestressing method under various working conditions are analyzed.In the finite element analysis of prefabricated main girder with upper camber,the additional stress produced by bending the upper cover plate into an arc plate and bonding it to the web of the main girder is added.(3)Based on the extended finite element method(XFEM),the crack initiation of the main girder of the metallurgical crane was studied under the condition of maximum stress,and the defects of manufacturing and welding were considered.Prefabricated cracks are used to simulate the crack propagation path,and then the stress intensity factor K is solved to draw a-N curve.The relationship between stress cycle number N and crack length a is expressed intuitively,the time period from crack initiation to critical crack size is evaluated,and the safe service life of crane is evaluated.According to the research task of the project,the static analysis of the main girder of the metallurgical crane is carried out,and the results of equivalent stress and deformation under various working conditions are obtained.It is inferred that the cause of crack initiation is related to the manufacturing and welding defects of the main girder.The dynamic simulation of crack growth is completed,and the a-N relationship between the number of stress cycles and the length of crack under crack growth is drawn.It takes 19.4 years to evaluate the ideal condition of crack growth from 0.5 mm of initial crack to 59.1 mm of critical size.