Analysis Of Overall Bending And Torsion Stability Of Boom Crane Structure

Since the reform and opening up,China's economy has made great progress,and there has been some progress in all areas of the national economy.More and more large-scale construction projects have risen.Engineering cranes have gradually entered people's field of vision with their huge load capacity and lifting capacity.It can meet the needs of large-scale nuclear power,wind power,hydropower and engineering construction projects.Among the structural forms of various types of engineering cranes,complex space combined boom structures are the most widely used.However,with the application of lightweight high-strength steel on the crane,the crane structure is developing in a more slender and towering direction,so the stability problem of the crane comes with the structural strength and rigidity.Many previous studies on the stability of cranes are mostly for the calculation and verification of stability of single-limb components,or for the analysis of the stability of the crane out-of-plane,without fully considering the coupling of bending and torsion.In the overall stability problem of the crane combination boom structure,there are still certain safety hazards in the design and application of the crane.In view of the above problems,this paper focuses on the integration of bending and torsion into the overall stability analysis of the boom crane.From the perspective of energy method,it provides a fast and efficient analysis method and idea for the engineers of the engineering crane industry.Firstly,the bending and torsion stability analysis of the end-loaded beam-column structure is carried out,and the bending-torsion balance differential equation of the member at the unstable position is established according to the second-order theory.Since the obtained equilibrium equation of beam-column structure is a variable coefficient differential equation,it is difficult to obtain an analytical solution.Therefore,the potential energy standing-value principle based on the energy method is selected for stability analysis.Assuming a deformation curve that meets the boundary conditions,the corresponding structural form can be obtained.The bending and torsion instability characteristic equation.The boom structure of the engineering crane is mostly a lattice structure,so it is necessary to analyze the equivalent problem of the lattice component and the solid belly component.Since the bending and torsion coupling needs to be considered in the overall stability analysis of the boom crane,it is necessary to discuss not only the bending equivalent problem of the lattice member and the solid belly member,but also the torsion equivalent between the two.The problem lays the foundation for subsequent stability analysis of the boom crane.Due to the complex combination of the boom structure of the engineering crane,it is necessary to first analyze the overall bending and torsion stability of the simple curved beam-column structure,assuming a deformation curve that meets the boundary conditions,and fully considering the deformation coordination conditions between the connected members.Then,according to the principle of potential energy standing value,the overall instability characteristic equation of the structure is obtained.The application of the pulling system on the crane introduces the non-conservative force,making the overall stability analysis of the structure more complicated.Since the bending-torsional coupling effect is taken into account in the overall stability analysis,it is difficult to obtain an analytical solution from the equilibrium equation,so the energy method is still chosen to perform the approximate solution.The stability analysis of the single-rod boom,the single-master crawler crane and the single-pillar main-arm combination crawler crane structure is carried out,and the non-direction force is considered reasonably.The instability characteristic equation of the corresponding structure is obtained and applied.The finite element software is verified.