Parametric Modeling And Strength Analysis Of TBM Cutter-head

As a special tunneling machine, TBM(Tunnel Boring Machine) is widely used in tunnel projects. A large number of studies on the mechanical properties and structural design of TBM have been carried out by domestic and foreign scholars. Finite element analysis is often used as an important assistant mean in these studies. However,establishment of a FEM(finite element method) model of an extremely complicated structure like TBM cutter-head is often a time-consuming work. In this study, a finite element parametric modeling and analysis system for TBM cutter-head was developed combining APDL in ANSYS with visual programming techniques in VC++.Firstly, on the premise of maintaining the structural pattern and characteristic sizes of the TBM cutter-head, reasonable simplifications were made on the detailed and less important structures. Sixty-one variable parameters were chosen to describe the structural characteristics and the geometry sizes of the cutter-head. A parametric modeling program was compiled based on APDL and several technical problems that should be paid attention to in the process of modeling were pointed out.Secondly, based on the TBM cutter-head modeling program in APDL, a series of user-friendly interfaces for inputting controlling parameters was established. The data transmission between ANSYS and VC++ was achieved and the identification issue of the input parameters’ rationality was resolved. Moreover, a parametric modeling system with good visualization has been programmed. The usefulness, convenience and reliability of this parametric modeling system were testified by creating a finite element model of a TBM cutter-head of four meters in diameter.Finally, finite element analyses were performed for the cutter-head constructed by this system in different working conditions such as normal working condition, ultimate bearing condition and unbalanced loading condition. The corresponding stress distribution and deformation were obtained for each condition. Conclusions were drawn through comparing the upsetting moments of all calculated working conditions. The results showed no direct correlation between the upsetting moment and the bearing force when the disc cutters are all loaded. The more serious the unbalanced loading is, the larger the upsetting moment will be. The cutter-head is under a more dangerous situation when the unbalanced loaded cuttersare situated at the bottom of the cutter-head than at other positions. This information may be of referential value for improving the design of cutter-head.The parametric modeling system for TBM cutter-head developed in this paper may to some extent provide assistance for the establishment of finite element model. The system can also reduce the workload of early stage of finite element analysis and shorten the period of structural analysis and TBM cutter-head design.