Research On Geometric Nonlinearity And Stability Of The Super-lifting Boom System Of Crane

With the increase of crane working height and working range,the crane boom is getting longer and longer,and the structure of the boom is gradually developed from a single boom form to a complex combination boom form,such as the installation of wind power equipment.The boom of the all-terrain crane introduces a super-lifting device.The introduction of the super-lifting device effectively improves the carrying capacity of the crane,but greatly increases the difficulty of analyzing the force of the telescopic main arm.In this thesis,the telescopic boom system of the truck crane with super-lifting device is taken as the research object,and the nonlinear deformation of any n-section telescopic arm and the static stability problem outside the lifting plane of the telescopic arm system are studied.The main research contents and methods are as follows.(1)The geometric nonlinear deformation problem of the telescopic arm under the action of spatially symmetric super-lifting cable is studied.The triangular region composed of the variable amplitude cylinder and the base of the basic arm is equivalent to an elastic support.and the equivalent mechanical model of the telescopic arm under the action of spatially symmetric super-lifting cable is established.Based on the small deformation theory,establishes the differential equation of the any n-section telescopic arm,derives the expression of the deflection of the telescopic arm under the action of the super-lifting cable,and uses the MATLAB software to write the program for numerical solution;the finite element software ANSYS For the platform,the finite element model of the super-lifting telescopic arm system is established by using the APDL language,and the nonlinear deformation simulation analysis is carried out.Comparing the theoretical analysis results with the ANSYS simulation results,the correctness of the derived deflection expression is verified.(2)The problem of out-of-plane stability of the telescopic arm system under the action of spatially symmetric super-lifting cable is studied.According to the deformation coordination relationship of the super-lifting cable and the telescopic arm,the static equilibrium equation of any n-section telescopic arm system is established,and the telescopic arm instability is derived.The characteristic equation is solved by using MATLAB software to solve the instability critical force of the telescopic arm.Using the finite element software ANSYS,the finite element analysis model is constructed by using APDL language,and the simulation analysis is carried out to verify the correctness of the derived instability characteristic equation.(3)Based on the research results of nonlinear deformation and stability analysis,the typical all-terrain crane telescopic arm system with super-lifting device is analyzed to verify the application of the research results in engineering practice.Finally,the influence of the structural parameters of the telescopic arm system on nonlinear deformation and stability is discussed,which can provide theoretical support for the design calculation of the telescopic boom system of an all-terrain crane with a super-lifting device.The results show that the deflection expression and the instability characteristic equation of the telescopic arm under the space-symmetric super-lifting cable are correct,which can provide a theoretical basis for the modification of the crane design specification GB/T3811-2008,and also provide the necessary technical support for the design calculation of the all-terrain crane telescopic boom system.