Damage Modeling And Finite Element Analysis Of Tower Crane Boom

Tower crane（hereinafter referred to as tower crane）is an important lifting equipment in modern construction,which can realize the horizontal and vertical transportation of heavy objects,but with the continuous increase of construction strength,the tower crane collapses during the work process the phenomenon of safety accidents such as broken arms and broken arms is also increasing,which has caused serious economic losses to the country.This thesis analyzes the tower crane accidents at home and abroad in the past 10 years,and finds that nearly 85% of the tower crane accidents are caused by the damage of the tower crane boom.Significance.Under this background,this thesis summarizes and summarizes the current status of damage simulation research at home and abroad,selects the QTZ80 tower crane as the research object,conducts damage simulation research on its boom,and constructs a tower crane based on the boom end of the boom.The main research contents are as follows:（1）A parameterized finite element simulation model of the QTZ80 tower crane is established.According to the structural parameters of the QTZ80 tower crane,the parametric section model of the beam elements commonly used in the tower crane is constructed by using ANSYS APDL command flow,and based on this,the parametric variable section beam element model is constructed,and the solid model is further constructed.The analysis results are closer to the parameterized variable-section beam-rod element finite element model of the tower crane.The materials and constraints of the finite element model of the tower crane are imposed by ANSYS APDL command flow,and five typical working conditions of the tower crane are selected according to the lifting characteristic curve of the tower crane for static analysis.The stress distribution of the boom under typical operating conditions enables parametric load application.By modifying the command flow parameters of ANSYS APDL,the rapid modeling of tower crane parameter optimization and the rapid establishment of other types of tower cranes in the same series are realized.Finally,the modeling command flow of the complete tower crane is packaged based on Delphi and ACCESS software.The development of parametric auxiliary modeling system for tower crane is presented.（2）Finite element modeling and analysis of corrosion damage and crack damage.Using the characteristics of parametric modeling,the corrosion damage model of the tower crane boom is established by reducing the local wall thickness of the boom.Using the method of parametric solid modeling,a parametric solid model is established at the corresponding position of the crack damage,and the crack damage model is established by breaking the continuity between the nodes;using the multi-scale modeling technology,the rigid area method is adopted Connect the solid model and the beam-rod model to establish a crack damage analysis model.The feasibility and accuracy of using the rigid area method to connect different types of elements is verified by the comparative analysis of the displacements and modal frequencies of the boom feature points of the non-damaged multi-scale connection model and the non-damaged beam-rod model.The discontinuities of the third,fourth and fifth lower chord sections of the QTZ80 tower crane boom were selected as the locations of corrosion damage and crack damage,and the finite element modeling and analysis of corrosion damage and crack damage were carried out.（3）Finite element modeling and analysis of pin connection damage.The simulation of the pin shaft connection structure（pin shaft and lug plate）is established by means of solid modeling,and the contact between the pin shaft and the pin shaft hole is set up,and the wear of the pin shaft is simulated by changing the radius of curvature of the pin shaft.The pin-shaft connection structure is connected with the beam-rod model by the rigid area method.The upper chord connecting pin between the third,fourth and fifth sections of the boom is selected as the connection damage simulation object,and the modeling and finite element analysis of the pin connection damage are carried out.（4）Research on the macroscopic characterization characteristics of different damage of tower crane boom.Based on the parametric finite element analysis model of the tower crane that has been established before,the ANSYS APDL command flow is used to construct a finite element analysis and displacement result automatic extraction system for the feature points of the boom,and the automatic analysis of the variable parameter tower crane model is realized.Studying the damage macroscopic characterization of tower crane jib provides a powerful analytical tool.Using the automatic analysis system,the macroscopic characterization of the displacement trajectory of the boom end characteristic points of the tower crane boom under different types（corrosion,cracks,connections）,different positions,and different degrees of damage is analyzed.Calculate the absolute value of the difference between the Y-direction displacement of the characteristic point of the boom in the damaged state and the Y-direction displacement of the characteristic point of the boom in the intact state,and construct the damage displacement map of the characteristic point of the boom.The trajectory map can know the damage position and degree of the boom,and provides a basis for the subsequent diagnosis of the damage status of the tower crane boom through the characteristic point displacement map.