Geometric Nonlinearity And Stability Analysis Of The Lattice Boom With Waist Line Structure

The high speed jump of our country’s economy drives the high speed of urbanization, the role, which construction crane plays,has become increasingly important. In order to achieve the purpose of high efficient and rapid urbanization, the weight of the construction crane and hoisting amplitude increase became the research hot spot, more and more of the hoisting machinery improve its lifting weight and lifting amplitude by adopting increase arm length of the layout of the frame structure. However, due to the introduction of the long arm shelf structure, which leads to the boom structure often appeared such problems as down-warping and lack of stability due to the large weight and self deflection. In order to solve this problem, in the process of engineering construction adopts the forms of single lever traction, double rod drawing and lumbar traction rope structure. At now, the researching theory for single rod traction and double rod drawing forms of boom structure has made great progress. But for the research of the boom structure with waist line structure is still in the exploratory stage, this topic is looking boom structure with traction bracing structure as the object,carring out indepth theoretical analysis ang giving the guidance,and provide theoretical support for the process of engineering design has become the researching tasks and goals of this topic.This paper has a model simplification of the structure of the boom structure with the waist rope structure, giving a reasonable force calculation model, it is concluded that the stress of the back pull rod and the waist rope structure, and its validity gets verified. Under the premise of the stress of the back pull rod and the waist rope structure is correctly guaranteed, the instability criterion expression of the boom structure with the waist line structure is obtained by combining the differential equation method with the corresponding boundary conditions, and the validity of the buckling characteristic equation is verified.In the process of deriving the instability characteristic equation, the simplified method of the lateral flexibility of the fixed point is abandoned, and the accurate model of lateral flexibility of the gauge and the solid support is used. When considering the lateral flexible and solid fulcrum, there is a certain influence indeed for the instability form of the structure through the analysis of the lateral flexibility of the solid fulcrum. On this basis, by using the equivalent moment of inertia, the unit load method and the method of comparing the displacement, it is concluded that the concrete expression of the lateral stiffness in the solid fulcrum of the shaft bracket structure, and it is also concluded that the influence factors of the lateral stiffness in the solid fulcrum of the shaft bracket structure, providing the theory support for reasonably control of the lateral stiffness of the solid fulcrum in the shaft bracket structure.Due to the structure layout length of the arm shelf structure increases, causing geometry nonlinear phenomenon of the boom structure is obvious. Under their own gravity, it is worthy researching and analyzing which form will the distortion of boom structure will take and which form will the deformation form of structure of the waist rope will take. This paper mainly studied the deformation form of the arm frame structure under the influence of gravity. And after getting the force in the waist line structure, By combining catenary method, it is concluded that deformation form of the waist line structure after loading. And its influence factors are discussed in this paper.