| The full-face tunnel boring machine(TBM)is a large and complex set of tunnel boring equipment that integrates the functions of tunneling,ballast removal,and lining.TBM encounters extremely high hardness and high quartz content surrounding rock boundaries during the tunneling process,which makes the system bear extreme strong shock and sudden external loads.At the same time,the TBM main system is composed of multiple systems such as mechanical,electric,hydraulics,and control.And its mechanical system includes subsystems with nonlinear dynamic characteristics such as main bearing system,gear drive system,and there is a time-varying load interaction relationship between different systems.This makes it difficult to establish a multi-disciplinary coupling model of the main system under extreme conditions,its dynamic behavior complex and difficult to predict.This directly affects the stability,life and tunneling performance of the load-bearing structure of the system,and ultimately leads to a series of abnormal damages to the key load-bearing parts of the TBM main system(such as large-area cracking of the cutter head body,fracture of the cutter head split connecting bolts,and key drive components overload,component sealing failure,etc.),serious engineering problems occur.In response to this problem,this paper established a coupling dynamic model of the main system.It revealed the influence of the electromechanical control multidisciplinary design parameters on the vibration response and load-bearing performance of the system.A design method of dynamic performance of TBM main system based on electromechanical control coupling mechanism is proposed.The main research work is summarized as follows:(1)TBM main system electromechanical control coupling dynamics modeling.Consider the real-time dynamic information interaction mechanism between the main system mechanical structure and multi-motor synchronization control,the relationship of multi-subsystem nonlinear strong coupling,and the establishment of electromechanical control coupling model based on load torque real-time interactive.Based on the actual measurement of engineering site vibration,torque and dynamic stress,combined with the dynamic response of the con ventional dynamic model for cross-comparative verification,the multi-disciplinary coupling mechanism of the electromechanical control of the main system is revealed.The study found that this coupling relationship significantly changed the load-bearing and vibration characteristics of the drive system.Under the combined action of strong shock and sudden external load,multi-motor asynchronous drive and dynamic intervention of synchronous control strategies,the motor output torque showed significant periodic fluctuation characteristics.The maximum output torque of the drive motor fluctuates more than 30%,which is an important cause of motor overload damage in actual engineering.The radial vibration of the drive gear exhibits periodic strong impact characteristics,and its maximum amplitude mutation reaches more than 260%.(2)Research on the dynamic behavior of the electromechanical control coupling of the TBM main system.Through the study of the inherent characteristics of the system,it is found that the system is prone to 1-3 order modal coupling vibration in the actual vibration.The rigidity of the system is highest in the axial direction,second in the longitudinal direction,and the lowest in the transverse direction.The calculation method based on parameter sensitivity analyzes the influence of the main quality and stiffness parameters of the system on the vibration characteristics of the system modes and their respective degrees,and the modal transition points under each dynamic parameter are obtained.By studying the non-linear variation of the vibration of the main components of the system along the tunneling direction of the main engine,it is found that the overturning vibration of the supporting shell has a significant "amplification effect",and its amplitude reaches 123.60%and 11 8.99%of the cutter head respectively,which should be focused on during the dynamic design.The dynamic load in each direction of the key load-bearing parts shows a non-linear decreasing trend,which provides a basis for the design of the load-bearing components of the system.(3)TBM main system dynamic performance design research:Based on the high-sensitive design parameters of the system dynamic performance,the dynamic performance design method that can be applied to the actual TBM manufacturing and construction is proposed for the two levels of the manufacturing stage and the on-site construction stage.The study determined that the optimal support angle of the main propulsion cylinder of the system is 82°.The optimal design radius of the main bearing radius is 2.2m.It is determined that the maximum load difference of the synchronous drive unit under the X-type arrangement is 37%smaller than that of the symmetrical arrangement.The secondary control strategy has better load sharing performance under strong shock and sudden load.On this basis,the dynamic performance of the main engine system under different types of rocks and main tunneling parameters is analyzed in detail.Provide design basis for the high stability performance design of TBM main system.(4)TBM main system quality coordination and vibration reduction structure design research:Based on the study of the dynamic characteristics of the TBM main system,the frequency modulation mass vibration reduction theory is applied to the TBM main system,and a coordinated mass vibration absorbing structure(TMD)design method that can be adapted to the actual tunneling process is proposed.The TBM-TMD dynamic model is established on the basis of the mechanical and electrical control coupling dynamics model of the TBM main system,and the kinematics and dynamics characteristics of the vibration damping structure are comprehensively considered to study its vibration absorption mechanism under typical strong shock loads,and the system is studied the influence of main design parameters on the system's damping effect.Under the action of the vibration damping system,the RMS value of the axial acceleration at the supporting shell is reduced by 8.88%,and the maximum amplitude is reduced by 1 1.67%.The RMS value of the acceleration in the horizontal overturning direction is reduced by 34.65%,and the amplitude is reduced by 35.36%.Finally,the virtual prototype model is used to verify the vibration reduction effect of the system.It provides new ideas for the design of the new-type damping structure of the TBM main system.(5)Engineering example application:Taking the actual TBM as an example,the system dynamics model is established by the mechanical and electrical control coupling dynamics modeling method of the main system in this paper,and the multi-point vibration measurement on site verifies that the model is accurate in calculating the vibration characteristics of the system.Based on the model,the inherent characteristics of the model and the vibration characteristics of key components are analyzed.On this basis,the design method of TMD is applied to design the vibration damping structure suitable for actual engineering TBM.Through the application of the damping system,the maximum axial and lateral overturning acceleration amplitude of system supports shell is reduced by 26.7%and 13%.The research in this paper provides a reference for TBM main drive system dynamic characteristic mechanism research and system dynamics design. |
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