The Study On Structural Calculation And Analysis Method Of Lattice-type Crane With Variable Cross-section Boom

With the demand of the engineering construction development, the development of crane is increasingly prone to large-sized, dominant-mountain and lattice. By the great deal use of the high-strength steel material, the structure strength is raised, but the problem of structural stiffness and structural stability is made to show to project. The stability analysis of complicated lattice structure becomes the crux of contemporary and large crane structure design and its calculation. The overall stability analysis of the crane's lattice jib with main and vice-jib structure is even more difficult to technician in our country. So it's very necessary to seek a simple, utility and effective method to solve the difficulty.By means of internal force analyses to the cantilever lattice structure such as the tower crane which with variable cross-section boom, a simple lateral movement formula is introduced. On the basis of this, the contrast of the algorithm is used in cantilever lattice structure and cantilever solid web beam, we can get the algorithm that can be used to calculate the equivalent inertia moment of the lattice structure when it is regarded as solid web beam.The application of finite element method in the stability analysis is studied by calculate the lattice structure's equivalent inertia moment in the different arrangements of web member, by this way to test the accuracy of the formula. The initial moment method is improved. So we can realize the equivalent between lattice structure and solid web beam without change its geometry dimension.The overall stability of crane's lattice boom with variable cross-section structure is studied. Use the related equivalent principle, turn the variable cross-section boom to the solid ladder cylinder. The accurate finite element theory is studied to give the fabricated stiffness matrix, by use of this, the calculation of Euler's critical stress which with variable cross-section boom is given. The equivalent method is applied to test the crane's overall stability and structural deformation. To analysis the boom-tower crane FZQ1650's model between the actual structure and the equivalent structure with the finite element procedure, the result show that the studied equivalent method has enough accuracy, it can be used in actual project.