The System Modeling And Finite Element Analysis Of Self-Climbing Structure Of Tower Cranes

With the demand of the engineering construction development, the development of increasingly towards high-rise towers, hydraulic jacking system is widely used for self-climbing tower crane building and disassembly, the problem about self-climbing safety made more obvious each day. Self-climbing is a task which needs people's operating in the altitude, as a result of the specialization of the task, the lattice structure is not steady at the moment, the situation of the force is very complex and not in common as the others. How to make sure the safty of self-climbing operating, becomes a big problem of engineering. Until now, either in domestic and international norms, or professional textbooks, there was no clear argument about the how to analyse the force and deformation situation of self-climbing task or optimize the correlative parameters. Neither nor the effect of wind to the strucure. Generally, the fabricant accommodates center of gravity of the whole struture to the hydro cylinder bearing point on the self-climbing frame, bases on experience and simple caculation. Faced with the complex self-climbing structure force situation, giving a reference to the theoretical guidance and practical engineering, and effective method, is the purpose of this thesis. This thesis seeks to do a little useful contribution in this respect.Self-climbing frame is pivotal struture in lifting task. Bases on the peculiarity of the lifting work, this thesis establish the self-climbing system model, analyze the influencing complication to the struture. With the exoterica dynam principle, this thesis analyzes the center of gravity of the upside struture, which determines the functionary guide wheels and their pressure. This thesis also makes sure the admeasure priciple of guide wheels, when the force situation of the structure is oriental. Taking luffing-jib tower crane as example, this thesis lists the function of the guide wheels, which contains influential complication as variables.In order to maximize the self-climbing structure force situation, gives out some reasonable policies for tower crane in the method of lifting admeasuring the pressure of the wheels. Based on the wheels funcion, analyse and find the optimal luffing-jib angle for the lifting task. As the different operating requirement of tower cranes, the structure design is not the same, it is difficult to satisfy the need of optimal lifting state only in the method of admeasure the luffing-jib angle for some cranes. To deal with this kind of problem, analyse and deduce the comparatively optimal lifting state, which satisfies the condition of force and deformation attainability. Combining with the common design principle for the counterbalance of tower crane, analyse and find the reasonable counterbalance which make the self-climbing structure in the green wood. Otherwise, for the sake of logical center of gravity position of the upside structure, this thesis also considers the method of carrying load on the luffing-jib, and makes a brief analysis.In order to caculating and analysing the situation of force and deformation for lifting task, this thesis builds up several finite element models based on whole self-climbing and upside structure in several different ranges, and verify the correctness and validity of the calculation, so it can be referenced to the actual projects and applications. With the use of finite element analysis software caculate and analyse the dangerous lifting task with the effect of lateral wind, compare and analyse the result with normal lifting task in different ranges, analyse the effect of lateral wind to the structure deformation ,force and otherwise.This thesis gives out several effective lifting strategy for tower crane's self-climbing safety, together with some method of parameter optimization. It verifies its correctness in the use of example, for the use and reference in the engineering.