Finite-element Analysis And Improvement On Girder Of Grab Double Bridge Crane

Grab double bridge crane is widely used in industrial production of lifting operation, the box structure of the main girder is the important one of the components, the strength and stiffness are well assured that it can meet the demand of practical production.This paper takes a factory workshop of practical operation 20 t bridge crane as the research object. The box girder of the crane which is much complicated in structure is welded with criss-cross steel plate. And it exists many problems of large deformation girder in use process, the structure is thin and need to be improved, the theoretical analysis and support of the strength and rigidity are also required.Obviously, large error can be caused for applying the classic material mechanics and structure mechanics analysis. In this article, the finite element of combination of the beam and board model is used to solve the difficult analysis problem. The dynamic load impact coefficient is determined, the box girder of double bridge crane is analyzed with the method of finite element analysis (FEA) and studied with stiffness and strength numerical method. From the results of the analysis, it is known that the error rate between finite element analysis and practical measurement results is 3.6% , So the finite element analysis result is reliable. On the basis of the above, four kinds strengthening programmes of the main girder are emulated and compared by finite element softwares. The strength of the best plan increases 38.7% and the rigidity increases 33.9% over the original beams.The above work provides beneficial theory reference for the reconstruction and reinforcement of the crane.