| With the increasing demand for oil for all countries, the oil exploitation develops gradually from land to the sea. It requires more for offshore hoisting as the number of offshore engineering increases and both the size and weight of the component increase. The hoist load of the floating cranes is becoming more and more large. Large hoist load floating crane mostly adopts the roller jacket slewing ring, however, the slewing ring can not met the requirements from an increasing weight. Therefore, a new type of sliding slewing mechanism is suggested. The sliding track surfaces of this slewing mechanism’s contact pressure are easy to be uneven distribution because of its structural characteristics, which in turn affect the life of the slewing ring and its performance.In this paper, the research object is floating crane sliding type slewing mechanism. In order to balance the slide contact surface contact pressure and Reduce the stress of structures as the goal, with ANSYS as the main tool, some methods are put forward to balance the slide contact surface like Enhance the support column stiffness, the position of the force is moved on the slewing table and the Sliding track stiffness is enhanced. In order to verify the accuracy of the method and results of the contact finite element calculation through the field test, design the scale experiment model according to the final structure and make the test plan.Firstly, the structure characteristics of slewing mechanism is analyzed and the way of simplify the finite element model is determined, the finite element model of the prototype of slewing mechanism with ANSYS is created, the boundary conditions and solution is determined. The possible reasons for the too large local stress and the uneven distribution of slide contact pressure are analyzed.The second, the improvement programs are put forward to equilibrium contact area pressure distribution from the four directions which are enhance the support column stiffness, the position of the force on the slewing table is moved, The Sliding track stiffness is enhance-d and the compression area of the slide track is increased. The slide contact pressure curve of different schemes are compared, improvement effect is determined. In view of the position of large stress, in order to reduce the large local large stress, some measures are taken, like Set up stiffeners, Increase the thickness of steel plate. Then, test model based on the scheme which contact pressure distribution is the most uniform is designed. Three forms of test model are put forward and the test model boundary conditions are determined. According to the different reductions ratio and the different structures. Using the calculation method of the prototype to solution the three kinds of test model schemes. The calculation results of three kinds of test model are compared with the result of the prototype, the schemes which the result most fit the prototype to be the test mold is chose.At the last, the test plan is designed based on the experimental model and the purpose of the experiment, the reference and propose is provided for field test.The research results of this paper provided some design ideas to equilibrium contact area pressure for the designer of huge floating crane. And some reference methods are provided to organization of large mechanical structure of small size steel structure model test. The conclusion is of practical value for engineering application. |
