The Numerical Simulation Research On The Welding Processof The TBM Main Beam

TBM is widely used in tunneling engineering. As the key component of the TBM host machine, the main beam bears the forces and torques from the cutter-head and passes it to the boots system. TBM main beam’s life and work quality directly affect the progress and quality of the tunnel engineering.TBM main beam is a typical box-beam structure which is manufactured by welding. After welding, the residual stress and welding deformation will be inevitably produced which can not be ignored. And they will have a great impact on the performance and lifetime of the TBM main beam and the whole machine. People in the past used the experimental method to get reasonable welding process which is a waste of time and energy. With computer technology’s development, the numerical simulation study of the welding process has been widely carried out. So in this thesis, we will select a part from the main beam where the stress is more concentrated under the actual conditions and extract the part to establish a simplified finite element model by the finite element software ANSYS. After that different welding process will be simulated based on FEM and thermoelastic other related theories. And finally get the temperature and the stress field,the paper studies as follows:(1) Select of the welding part from the main beam: apply the actual load to the TBM main beam by using finite element software ANSYS Workbench and perform static finite element analysis to identify the part where the stress is more concentrated. Then take this part as the research object.(2) Establish the welding FEM: based on the actual welding process and select the typical welding structure of the roof and web as the analysis objects. And build a welding finite element model including a multi-pass welding by using APDL.(3) Numerical simulation of the welding temperature field: determine the welding technology programs and select the appropriate welding parameters for the welding process. Then simulate the welding process, and get the temperature field, then analyze and discusse.(4) Numerical simulation of the welding stress and strain fields: use the method of heat-stress coupling analysis and take the results of the temperature field as the preparation conditions. We simulate the stress and strain under different welding process and the simulation results are analyzed and discussed in order to obtain a reasonable welding sequence program, which can provide a theoretical basis for the selection of the actual welding process sequence.(5) Use the blind hole drilling method to measure the residual stress of the font welding sample. And then the numerical simulation results were compared to verify the reasonableness of the simulation results. At the same time it will prove that the selected welding program sequence is reasonable.