Research On Coupled Vibration Mechanism And Passive Damping Of Anchor Drilling For Mine Support

Roof bolters are the key mechanical equipment for coal mine support.At present,the development of coal mine roadway support technology tends to be intelligent.The bolt drill is gradually replaced by mechanical arm clamping by manual holding.During construction,due to the comprehensive excitation of different geotechnical parameters,axial thrust and torque,the drill pipe produces complex vibration phenomena,and various vibrations interact with each other to form nonlinear coupling vibration.The excitation of each degree of freedom of the drilling rig system is transmitted to the base along the vibration of the mechanical arm,which makes the anchor drilling mechanical arm vibrate violently.Its vibration problem restricts the improvement of the support effect of the coal mine roadway.In order to overcome the above problems,it is of great value to explore the coupling vibration mechanism of the anchor drilling,the vibration transmission mechanism of anchor drilling machine along the mechanical arm,and the design method of passive shock absorber.Based on the energy method and the finite element method,the transverse,longitudinal,and torsional coupling vibration dynamic model of drill pipe is established.Through the element connection sequence,the overall mass,stiffness,damping,and force load matrix are assembled,the expression of drill pipe boundary conditions is established,the six degree of freedom dynamic reduction model is studied,and the law and change trend of longitudinal transverse torsional coupling vibration of drill pipe are explored;In order to explore the vibration transmission mechanism of the rock bolt drill along the manipulator,the base response amplitude matrix is established through the modal superposition method,the external load of the manipulator base response point is explored by using the force Jacobian matrix,and the six degree of freedom frequency response function of each subsystem of the manipulator is studied by using the multi-level transfer path analysis(MTPA)method to explore the vibration response of each degree of freedom of the manipulator base;Through the design of a multi-degree of freedom high-damping viscous fluid shock absorber,the expression of the fluid and spring fluid coupling damping coefficient of a circular through-hole is studied,and the best parameter design scheme is selected through the orthogonal experimental method,trying to achieve the best damping output effect of the shock absorber.The main research work and achievements of this paper are as follows.(1)The longitudinal transverse torsional coupling vibration mechanism of bolt drilling is studied.Based on the energy method and finite element method,the transverse,longitudinal and torsional coupling vibration dynamic model of drill pipe is established;The global matrix is assembled in the order of unit connection;Taking drill pipe drilling as the boundary condition,the reduced order model is constructed;The simulation of mudstone drilling shows that the vibration displacement of drill pipe from large to small is as follows:longitudinal,torsional and transverse vibration displacement,and the longitudinal and torsional vibration displacement of drill pipe tail end are reduced by 93.2% and 84.7% respectively compared with the drill bit.The disturbing force and reverse torque are the main reasons for inducing the coupling vibration of drill pipe.(2)The mechanism of vibration transmission along the mechanical arm of roof bolter is studied.Based on the multi-level transfer path analysis method and modal superposition method,the vibration transfer model of the subsystem composed of each joint of the anchor drilling manipulator is established,and its frequency response function matrix is established;The force Jacobian matrix is used to analyze the stress of the excitation force of the drilling rig transmitted to the base along the manipulator,and identify the external load on the response point of the base;The vibration response and formant frequency of each degree of freedom of the base are obtained.This paper reveals the transmission law of the vibration of the roof bolter along the mechanical arm,which provides a theoretical basis for the development of vibration reduction technology and the design of vibration absorber.(3)The mechanical structure of multi degree of freedom high damping viscous fluid damper is studied.Based on the principle of passive vibration reduction,multiple spatial degrees of freedom vibration reduction are realized by using solid elements,spring elements and viscous fluid.Each spatial degree of freedom has its corresponding vibration reduction device and method,and multi degree of freedom vibration reduction can be carried out at the same time,which lays a foundation for the subsequent exploration of the best vibration reduction performance of the shock absorber.(4)The optimum damping coefficient of multi degree of freedom high damping viscous fluid damper is studied.Using the coupling vibration,the vibration transmission mechanism along the manipulator and the mechanical structure of the shock absorber obtained in(1),(2)and(3),the fluid and fluid spring coupling damping coefficient equations are constructed through the generalized Bernoulli equation and dynamic equation;Using the orthogonal experimental method,the flow field analysis and spring fluid coupling dynamics simulation are carried out successively through Fluent and Simulation to determine the influence of relevant parameters on the damping output.The theoretical analysis shows that the vibration amplitude of each degree of freedom of the base is reduced by 68.32%,49.82%,52.17%,49.01% and57.09% respectively.