Research On Performance Simulation Analysis And Muti-objective Optimization Design Technology Of The EPB Shield Cutter

The cutter that engaged directly in cutting the soil, is the key component of the shield system, and its performances in the process of excavation are vital to the shield excavating quality. Combining the 973 project "TBM Boring System Performance Simulation and Experiment" with the enterprise's specific needs, author do the research on performance simulation analysis and muti-objective optimization design technology of the EPB Shield Cutter, putting forward cutter parametric modeling based on the structure characteristic, cutter fatigue life prediction based on the geometric similarity, cutter multi-objective optimization design based on the NSGA-I1 algorithm. These methods have been applied to the performance simulation analysis and muti-objective optimization design of the EPB shield cutter made by Shenyang Heavy-duty Machinery Group Co.,Ltd.In the 1th chapter, it mainly introduced the performance simulation analysis technology and the structural fatigue life analysis technology based on FEA, highlighted the domestic and foreign research state of the EPB shield cutter design and performance simulation, and proposed the studying content and organizational structure of the paper aiming at deficiencies existed in the current cutter structural design.In the 2th chapter, aiming at the problems of complicated cutter modeling and uneasy to optimization design at the later stage in the process of finite element analysis of the cutter, it proposed the cutter parametric modeling based on the structure characteristic. This method analysed structural characteristics of the cutter firstly, and modeled the cutter parametric struture by combining the characteristics based on the tree ladder relation and topology relation among the cutter characteristics. The cutter parametric modeling module was achieved by doing the secondary development of the finite element analysis software ANSYS. The cutter parametric model was established by using the cutter parametric modeling module, the finite element simulation models of the stress characteristics and vibration characteristics were set up based on the material properties and load situation of the cutter, and the stress distribution and vibration performance under varieous load operating conditions were gotten. In the 3 th chapter, aiming at the large forecasting deviation of the cutter fatigue life prediction caused by the various characteristics of the S-N, it put forward the method that doing the cutter fatigue life prediction based on the structure geometric similarity. The method meant that classifying the gap structures, identifying the geometric similarity criterion and geometrical similarity degree calculating method based on the fatigue properties by analyzing the main influences of the complex structure fatigue strength, amending the derived cutter S-N curves based on the fatigue properties of the matching standard structure and the geometrical similarity degree, selecting the positions that happened fatigue failure easily of the cutter gap structures according to the fatigue damage factors such as the average stress and the stress concentration, getting the load spectrum caused maximum fatigue damage of the location by using the Goodman equation, and predicting the cutter fatigue life by using Palmgren-Miner cumulative damage theory.In the 4th chapter, aiming at the problems that several positons of the cutter existed large average displacement and low fatigue strength, the multi-objective optimization of the cutter design parameters was carried out; taking the smallest displacement of nodes,the longest fatigue life and the maximum cutter aperture ratio as the optimization objectives. The multi-objective optimization mathematical model of the cutter was set up based on the cutter's detail structure distribution.Through the integration of the softwares iSIGHT and Ansys, the Pareto set of the cutter's optimal result was gotten by NSGA-II algorithm,and the best design parameters of the cutterwere obtained from the cutter's optimum Pareto set based on the fuzzy set theory.In the 5th chapter, it summarized the paper's research content and key work, and outlooked the endeavor orientation of the future research.