Analysis Of The Force Transmission Characteristics For The Thrust System In Main-beam TBM

The thrust system is one of the key subsystems of a full face rock tunnel boring machine（TBM）.It requires bearing the heavy payload, interrupt dynamical payload and intenseimpact payload which come from the bad environment where the TBM works. If the forcetransmission distributes badly, it is easy to cause unbalance force load. This case will certainlyresult in heterogeneous force distribution, which means the force of one certain body joints istoo large，and easy to cause the supercharge of the oil cylinder. On one hand, the short-timesupercharge of the force which body joints bear will influence the working life of the thrustcylinder and it surely will reduce it if it lasts for a long time. On the other hand, the unevenforce distribution on the cutter will lead to the supercharge of local stress and enormouslyincrease the possibility of tool damage and cause the rupture broken and height difference ofthe segments. Combined with the theory of robot mechanism, the kinematics of parallelmechanism and kinematic differential relationship, several research works on the main-beamTBM are investigated in this dissertation and are described as follow:1. Expound the research background and significance of the subject; summarize thecurrent situation both domestic and overseas of full face rock TBM, thrust system and forcetransmission performance, then put forward the main research content.2. By analyzing the force on the main-beam TBM when digging forward in the tunnelingcourse, summarize three resistances which the thrust system must overcome，based on themechanical model for driving system and provided a theoretical basis for further research onforce transmission distribution of the thrust system. Introduce the concept of theforce transmission distribution, and establish definitions for force transmission distributioncombined with the standard deviation formula.3. Establish the3-D model of main-beam TBM by using SolidWorks and then draw itskinematic diagram by using CAD. Research the general-purpose expression of the position ofthrust system and the speed of every component then create the velocity Jacobi matrix, layingthe foundation for next chapter.4. According to the last chapter of Jacobian matrix are obtained, get the force of Jacobimatrix of main beam thrust system. MATLAB program is applied for the simulation analysisof the force transmission distribution and conclude the main influence parameters. Byanalyzing the magnitude of the max force of body joints corresponding the merits offorce transmission distribution, verify the rationality of the evaluation index.5. Based on the force transmission distribution, aimed at the optimum of force transmission distribution, build the optimum function and optimizing thestructure size parameters of thrust system. The examples of optimal design ofgenetic algorithm in MATLAB toolbox are presented.