Numerical Simulation Research On Damage Of Tower Crane Bolted Connection Tower

In recent years,safety accidents of tower cranes(hereinafter referred to as tower cranes)have occurred frequently in China,causing immeasurable personal and property losses and bad social impacts.Among them,the frequency of overturning accidents caused by damage to the steel structure of the tower body occurs frequently The highest,in the early stage of tower damage,timely identification and control can effectively avoid accidents;the current damage identification technology is supported by a large amount of data without noise interference,but for towers with many models and complex environments such as construction sites As far as the tower crane is concerned,it is undoubtedly difficult to obtain reliable data;in this case,numerical simulation can provide a data basis for the damage identification technology of tower cranes,and at the same time in tower crane design,optimization,structural analysis,safety assessment and It plays an important role in detection and so on.In order to solve the problems of low accuracy,complex modeling and low work efficiency in the current numerical simulation of tower crane and tower structure damage,this thesis studies the numerical simulation of bolted tower damage,and determines the appropriate numerical simulation method,and an auxiliary modeling system was designed.The finite element analysis of the whole tower crane was carried out by using the determined numerical simulation method,and the displacement and change law curves of the top of the tower body were obtained and studied.The specific research content of this thesis is as follows:Firstly,the simulation method of tower beam element is studied and the auxiliary modeling system is designed.Taking the two standard sections of the FP6010 tower crane as the research object,the beam element tower model of variable section and constant section was established by using ANSYS software and APDL command flow.Through the comparison of simulation and experimental results,it is found that the two simulation methods have certain accuracy,but the tower body model of the variable section beam element is more accurate;in order to efficiently and accurately build tower bodies of different sizes Model,relying on DELPHI development tool and APDL command flow,designed a beam-rod element auxiliary modeling system for flat-top tower crane square tube tower body.Secondly,the numerical simulation method of bolted tower body damage is studied.Relying on the finite element theory and the lateral load experiment of the tower body,the numerical simulation method of the damage of the bolted tower body is determined,including the numerical simulation method of the bolt loosening,the fracture of the steel structure and the corrosion of the steel structure;among them,the bolt loosening and steel structure fracture are multi-scale The modeling idea is simulated,the damaged part is modeled,and the corresponding methods are used to describe the damage details for different damage types,and then the beam elements are used to establish the remaining parts,and finally the two parts are connected;based on the lateral load experiment of the tower body,the demonstration The rigid area method is established as a better connection method for 3D solid element and 3D beam element.At the same time,the feasibility of the numerical simulation method for bolt loosening proposed in this thesis is verified.The corrosion of steel structure is simulated by reducing the section wall thickness of beam element.The corresponding modeling methods and processes are introduced in detail.Finally,the finite element analysis of the damage of the FP6010 tower crane is carried out and the influence of the damage on the top displacement of the tower body is studied.Using the numerical simulation method determined above,the complete model of the tower crane with different damages is established,and the simplification and connection of each position are dealt with,and the corresponding constraints and loads are applied to the models respectively.The stress distribution diagram of the tower body;the difference between the tower body top displacement in the damaged state and the intact state of the tower body is analyzed,and the law of the influence of each damage type of the tower body on the top displacement of the tower body is obtained.Identifying tower damage provides technical and data basis.