Performance Analysis Of Gantry Crane Girder Skin Structure

At present, portal crane is the largest use of lifting equipment, the lightweight design is very necessary to it. conventional box structure optimization design of gantry crane is usually with girder, leg and fluctuation beam section size to the design optimize variables. The current research literature while using a variety of optimization methods, but due to its structure limitation, various optimization methods to reduce the weight of the structure will not have too big breakthrough. Reference the aircraft wing and steel structure building skin effect, puts forward a new type of portal crane structure, discusses from the structure to realize the lightweight design.In this paper, taking the 50t-26m portal crane girder as an example, the skin structure girder, legs, upper and lower beam using plate structure, analysis and optimization based on the finite element software ANSYS. Plate structure with shell element shell63 in ANSYS simulation, beam4 simulation of truss structure with beam elements, lifting trolley, crane and other centralized quality simulation unit mass21. The new type diaphragm girder structure mainly adopted the combination of thin-walled box structure and truss structure connection. The establishment of skin structure of gantry crane and gantry crane box structure model in ANSYS. Through the finite element analysis results, the feasibility of advantages and disadvantages of two models in static performance strength, stiffness and other aspects and draw new structure. Compared with the ordinary box girder structure, the weight of the structure of the box girder diaphragm structure is reduced by 11.3%, saving steel is about 6.4t.The static and dynamic analysis of the skin structure girder crane, first calculate the strength of the portal crane under different operating conditions and stiffness of the weak link, strengthening of processing, and then the modal analysis and harmonic response analysis, extract the key frequency value, natural frequency in the vertical direction of the skin structure of portal crane system is 3.978Hz, the recommended value in 2Hz-4Hz, the dynamic stiffness to meet the requirements. The analysis of influence of chord thickness, slenderness ratio and web member system on the structure, so as to provide the basis for rational design of skin structure. According to the calculation results, suggest that when the load is below 20t when the form of the vertical rod structure, when the load is 20t to 50t, with a vertical bar form, when the load is above 50t with vertical rod and vertical rod form.By using the method of analyzing the sensitivity of the ANSYS software, determine the size parameters are sensitive to the structural quality and dynamic performance effect as the dynamic optimization design of variable structure design, with quality as the objective function to optimize the design, the optimization scheme and the analysis of the ratio, the optimal structure of quality than the original skin type girder structure design reduced 12.06t, reduced steel reached 18.37%, realize the lightweight design, reduces the manufacturing cost.The optimized structure of the eigenvalue buckling analysis, select the region span lattice girder web and established the finite element model for buckling analysis, obtained buckling amplification coefficient, a buckling load amplification factor, the case of skin sheet, the critical buckling load of 104.8MPa, and analyzed the influence factors of skin plate buckling load of main girder.