The Study Of Stability In Lattice Type Boom Of Crawler Crane

Crawler crane has been widely used in modern engineering construction, and with the actual demand of manufacturing and engineering, Crawler crane has been developed to the direction of larger tonnage and longer boom. As the main bearing structure, the demand of bearing ability and stability of the boom become more and more imporement, so we studied the second kinds of instability which also named extreme point buckling.The geometric parameters of crawler crane boom has a direct impact on the design quality and the layout of the whole and the performance. Whether the stability meet the requirements has a directly impact on the boom arm smoothly and crane load success. Based on this, this paper mainly do the following research:(1) On the principle of steel structure design and from the origin of design it is based on the most basic parameters such as hoisting and amplitude to confirm the main geometric parameters of the basic boom,such as, the height of basic boom cross-section, the length of boom cross-section, the weight of boom, the cross-section area of main rod, two legs width of basic boom, the maximum length of boom. Provide a reference for the preliminary design of boom and create conditions for the detailed design.(2) For the stability of static boom, studying from the theoretical analysis and finite element analysis. For theoretical analysis,there are two ways to get the critical force,one way is through Classical Euler's formula,the other way is by the formula in the theory of elastic stability,which consider variable cross-section& uniform gravity& shearing force. The ansys analysis uses two methods:linear (eigenvalue) buckling analysis and nonlinear buckling analysis. Convert the critical force under the theoretical analysis and finite element analysis,we can get the correctness of nonlinear buckling analysis and the formula in the theory of elastic stability, and they can verify each other.(3) Hyperstatic boom system has multiple support points. For this kind of boom'stability, firstly, calculate the force of waist rope & the force of support rope & the stress of boom& the deflection of boom along with the change of waist rope parameters. The waist rope has three parameters:the length of waist rope & the angle between waist line and the center line of the boom & the distance between the waist line and the boom head. Then compiling the proces of the calculate into progrom, and making the waist line parameter variation's chat of the force and bending of boom, and preliminary determined the scope of the waist line parameters. finlly, seting the force of waist rope & the force of support rope & the stress of boom& the deflection of boom as objective function, by adopting the method of multi-objective optimization, getting the waist rope parameters for which the objective function is minimum. System presents the theoretical arithmetic and optimization process of crawler crane' longest main boom with waist rope device.