Research On Dynamic Modeling And Cohesion Method Of TBM Thrusting Mechanism

The TBM thrusting mechanism is one of key subsystems of large-scale tunneling equipment.Its working environment is harsh.Due to extreme heavy pay loads,large abrupt pay loads and strong vibration pay loads,the thrusting mechanism must have high rigidity,large flexibility and vibration stability to be normal,digging safely.Therefore,the establishment of a low-dimensional,high-precision dynamic model of the TBM thrusting mechanism can meet the needs of optimal control of the mechanical power of the thrusting mechanism during its tunneling process.This paper aims to establish its static stiffness model to analyze the static stiffness characteristics and stiffness sensitivity of the mechanism,then,establish its dynamic model to analyze the vibration characteristics of the mechanism,and then use the degree of freedom condensation method to establish a dynamic model based on the proposed dynamic model.The cohesion model of,in order to carry out the optimal control of its dynamics.Focusing on the above issues,the following research work has been carried out:1.The research background and significance of the proposed methods are discussed,and the domestic and foreign research status of TBM and thrusting mechanism,dynamic modeling and cohesion technology are reviewed.Aiming at the problem that the TBM thrusting mechanism is difficult to optimally control its dynamics in operation,a scientific method of how to establish a low-dimensional thrusting mechanism dynamic model under the condition of ensuring the calculation accuracy is proposed.The main research content is given.2.The calculation formula for the stiffness of the hydraulic thrusting cylinder and the basic motion equation of the mechanism are established,and the static stiffness model of the mechanism is obtained according to the mechanism deformation coordination equation and the dynamic compatibility equation.The validity of the static stiffness model is verified by the finite element method.The sensitivity analysis method is used to analyze the relationship between the stiffness of the mechanism and the size of the structure and the relationship between the stiffness and the pose of the mechanism.The results show that the pose of the mechanism has almost no effect on the stiffness of the mechanism,and the stiffness of the mechanism changes regularly with the change of the structure size.3.According to the static stiffness model of the mechanism established above,the Lagrangian dynamics method was used to establish the dynamic model of the hydraulic thrusting cylinder structure,and the finite element method was used to verify the validity of the model;the Newton-Euler method was used to establish the support ring The sub-structure dynamics model,combined with the basic motion equation of the mechanism,uses the sub-structure synthesis method to establish the dynamic model of the thrusting mechanism.According to the engineering example parameters,the natural frequency and mode shape of the mechanism are analyzed.The results show that the first-order vibration mode of the mechanism is mainly the axial offset vibration of the moving platform,and the second and third-order vibration modes are mainly the transverse torsional vibration and vertical vibration of the moving platform.Torsional vibration,the fourth-order vibration mode is mainly the axial offset vibration of the piston rod of each hydraulic thrusting cylinder and the hydraulic oil.4.According to the dynamic model of the hydraulic thrusting cylinder,the dynamic and static aggregation models were established,and the differences between the two aggregation models were compared;the static aggregation models of the thrusting mechanism under three different aggregation modes were established,and various aggregation modes were analyzed.The first four natural frequencies and vibration modes are compared with the first four natural frequencies calculated by the dynamic model when the thrusting mechanism is not condensed.The results show that the condensing model with the following condensing mode is the best.