Comparative Research On Mechanical Properties And Optimization Of Tower Crane Jib

Tower cranes are widely used in the field of high-rise building, power station, irrigation, and shipbuilding. Jib is one of the most important components of the tower crane and the quality of structure design of the jib has a great impact on the performance of the whole machine. With the development of tower crane toward to bigger lifting capacity and larger working radius, two new kinds of jibs, double lifting points continuous jib with a strut and double lifting points discontinuous jib with a strut, derived from the traditional double lifting points jib. At present, two new kinds of jibs haven’t been widely used in domestic and foreign manufactures and the comparative research on mechanical properties and optimization of the three different kinds of jibs is little, so it’s necessary to carry out the research in this field.In this paper, three different kinds of tower crane jibs are the research objects, the research contents including the comparative research on mechanical properties of the jibs and the optimization. The main jobs are summarized as follows:(1) Calculation method of internal forces of the jib system is studied. The calculation model of double lifting points continuous jib with a strut is established and the calculation formulas of rod internal forces and jib internal forces, using unit force method and graph multiplication method, are given.(2) Calculation software of mechanical properties of tower crane jib, based on MATLAB/GUIDE, is programmed. The using method and functions of the calculation software are demonstrated, using a double lifting points discontinuous jib with a strut as the example.(3) Comparative research on mechanical properties of three different kinds of jibs, under the same lifting capacity and the same typical calculation conditions, is studied. The contents including the comparative research on jib stress, rod tension force and cap head axial force.(4) Structure optimization of a double lifting points continuous jib with a strut, based on ANSYS Design Opt, is studied. In the optimization, the non-uniform of the jib stress is as the objective function, the positions of the lifting points and the hinge points are as the variables parameters. The optimization effect is good.