Study On The Topology Optimization Of The Track Plate For Large Crawler Travelling Unit

This thesis combines the project of"the development of three- support six-crawler travelling unit", which from the cooperated project of national key mining machinery enterprise, focus on the topology optimization design to track plate of the crawler travelling system in the 2100 tons bucket wheel excavator.For the crawler travelling system has lower requirements on ground condition, it can drive in mine, sea, swamp and other environments. Therefor, the crawler travelling system obtained the full application in military, engineering machinery and agricultural machine territory. The failure of each piece of track plate will affect the working condition of the whole machine, and the large number of the track plate holds a larger proportion in the crawler travelling system. If the weight of track plates is too heavy, it will affect the power of the engine, increase the fuel consumption, and shorten the valve life. Therefore, the optimization of track plate has great significance on improving the comprehensive performance of the machine and energy conservation.Although the development of the engineering machinery is later in China, it has already meet the needs of domestic and international markets demands, to a great extent, promoting the development of national economy. Large-scale is the trend of the market development.Topology optimization refers to the shape optimization. The essence is seeking the best stuff allocative decision in the optimization of the loaded object. There are two kinds of fundamental: degradation principle and evolutionary theory.The basic thought of the degradation principle is"subtraction", added all possible stuff before optimization, then modeling a proper optimization model, substract unnecessary stuff gradually through select the reasonable optimization method. It will not stop until get the final topology optimization shape.The basic thought of the volutionary theory is the random seeking of the theory of evolution; it introduces the mechanisms of natural selection, survival of the fittest and surviving the high-quality and eliminating the bad-quality in topology optimization to get the best topology.In referring to relevant literatures of the crawler travelling system and topology optimization, this dissertation summarizes the study status of them.On the base of SIMP, to optimizate the track plate under main load combinations through Optistruct. The main working and contents are as follows:(1) Reading some reference books about force analysis on the crawler travelling system, then calculate the results in any working condition preparing for below.(2) In this paper, the contact analysis is an important part. It is also an important nonlinear characteristic of ANSYS.Analysed the track plate stress under working conditions of tension, pressure, climbing and turning.(3)This paper introduced the development course of topological optimization, and some topological methods based on FEA.Mainly derived mathematical model of variable density method.(4) Optimizate the track plate under main load cases combinations through Optistruct. Through adjusting the ground Elastic Modulus to validate ground stiffness on the distribution of the track plate materials. Finally choose the appropriate ground stiffness tooptimize the track plate.The objective function of topology optimization is the minimum of weighted compliance for each working condition. The constraint condition is reducing the volume to 30% of original design volume. Discrete variable is 3.(5) Process the topological optimization results, and conduct it by finite element analysis. Compared with the stress of original track plate.