Studies On The Steel Structure Of The Large-tonnage Double Rotary Railway Crane Turntable System

Nowadays, cranes have been the necessary equipments to ensure smooth rail and deal with sudden accidents. Turntable is of key importance as the major loading component.The weight and structure have a large extent affect on the performance on the railway crane.Therefore this article takes QTJS160type crane as the background, which is developed by our country independently, as the research background. Hoping to do some contribution to the development of railway crane for the motherland in the future.In this paper, after studying the railway crane development situation of inland and abroad, and comparing the two kinds of rotary scheme for the advantages and disadvantages, design for QTJS160type crane preliminary scheme of double rotary mechanism is put forward, based on the lightweight scheme of initial design, the main contents are as follows:1. Creatively applying topology optimization technology to the railway crane turntable structure lightweight design, the minimum compliance of the turntable structure lightweight design, the minimum compliance of the turntable structure as the objective function, the optimized with constraint conditions, the volume of the common topology optimization scheme is studied and mathematic calculation method, deduce the Lagrange Multiplier method to solve the topology optimization problem of variable density method, based on variable density method, and make the mathematical model of topology optimization of turntable institutions. Based on the collaboration simulation platform ANSYS WORKBENCH, accomplish the establishment of the upper and lower initial structure of the parameterized model of the turntable, with the use of Shape Optimization module to complete the initial model of topological optimization design. By the manufacturability treat, a new rotary table structure is presented. Upper and lower turntable mass distribution fell by39.41%and41.89%respectively. The lightweight effect is significant.2. Due to the initial value of the turntable structure thickness after topology, and some dimensions are not yet accurate, so after the statics analysis, discovering that surplus materials still exist through the topology structure. A further lightweight design is needed. Firstly through the sensitivity analysis, find out the factors which have large influence on the stress of the rotary table structure and quality to set as the variables. Overall quality as the optimization objective function, the material allowable stress as constrain conditions. Later, through the Central Composite Design to determine the optimal design calculation sample, response surface is established, and through forecast alignment and correlation parameters to evaluate the established response surface, the result is ideal. Then based on the MOGA(multi-objective genetic algorithm), the dimension optimization of the turntable structure is accomplished, and take statics analysis of the optimized results. The conclusion is the optimized turntable structure accord with the requirement of material strength and stiffness, and compared with the result of topology, the upper turntable quality fell by34.74%, and the lower also has a4.16%drop. Then the combine simulation analysis of the optimized structure, after proofreading, the conclusion is that the optimized turntable system meet the design requirements.3. After the turntable system statics, a series of analysis of other aspects are completed. Including:dynamic analysis of the turntable system, buckling analysis and nonlinear analysis. In the dynamic analysis, extract the first six order frequency through the Block Lanczos method. The first-order frequency of the whole structure is0.63883HZ, which is in a lower value, easy to produce resonance, so the counterbalance needs outrigger to keep its stability. In the harmonic response analysis. From the result of the amplitude response curves, under different frequency of the excitation load, the amplitude response peak appeared in the fourth order (frequency of3.5181Hz), therefore it prone to produce resonance in the fourth order. In the buckling analysis, taking the first order buckling load coefficient, the turntable buckling load is63069N. Converted to quality, it will cause the buckling instability of the turntable while the counterweight reached63.069t in the condition that the balancing counterweight telescopic arm stretched. So the quality of the counterweight in the condition is within the scope of security. From the nonlinear analysis on the turntable system, it shows that the stress distribution is more uniform in the linear analysis. While considering frictional contact, it leads to local stress surge in the shaft hole inside because of deformation in the bottom of the cylinder shaft. It is easy to have a crush. So the inner side of the shaft hole need to guide the rounded edges in the process of production, in order to avoid the worn shaft hole due to excessive stress and reduce the phenomenon of life.