Design And Dynamic Characteristics Research And Analysis Of Dumping Arm Conveying System Of Spreader

The spreader plays an important role in the open-pit mining process,which can replace trucks to transfer the rock and soil to the spoil ground efficiently and quickly.With the development of open-pit mines in China,the application of soil discharger is more and more extensive.At present,there are many problems in the use of the spreader,such as large vibration amplitude of the discharging arm,large rock soil impact at the transfer place,and serious equipment wear or impact damage.Therefore,this paper takes 4500t/h spreader as the research object,designs and selects the relevant parts of the discharge arm conveying system,and establishes the relevant model,then studies the conveying system of the discharge arm during the working process of the spreader,and solves the vibration characteristics of the discharge arm through theoretical calculation and software simulation.According to the simulation results,this paper improves the buffer support scheme at the transfer place to improve the buffer performance of the buffer support device;Then improve the transfer chute to reduce the impact of rock and soil on the discharge arm,reduce the vibration amplitude of the discharge arm,and improve the strength and service life of the equipment.This paper design and select the parameters of the parts of the discharge arm conveyor,establish the dynamic model of the conveyor belt,establish the threedimensional model of the relevant parts of the discharge arm by Solid Works,analyze and calculate the load and excitation of the discharge arm.ANSYS Workbench is used to study the vibration characteristics of the discharge arm,and the stress and deformation of the discharge arm under typical working conditions are solved,the strength and stiffness of the discharge arm under static conditions meet the requirements after checking.Taking the simulation results as the input,the deflection formula of the discharge arm is derived,which provides a theoretical basis for the design of the discharge arm.Then,the modal analysis of the boom and the conveyor frame is carried out,and the natural frequency and the modal shapes of each order are solved.Combined with the excitation analysis,the possibility of resonance between the boom and the conveyor system is discussed,and the frequency easily causing the resonance of the boom is found.Finally,the wind load and rock and soil impact force are simplified into simple harmonic load.Combined with the modal analysis results,the harmonic response analysis is carried out to solve the steady-state response of the discharge arm under the action of simple harmonic impact.The conclusion is that the wind load has little influence on the vibration of the discharge arm,the rock and soil impact force at the transfer place has great influence on the vibration of the discharge arm,and the rock and soil impact force has great harm to the equipment.This thesis improves the buffer support scheme of the transfer place,compare and analyze the support device with buffer idler group and buffer bed.Through static analysis,modal analysis and harmonic response analysis,the static strength,stiffness,natural frequency and steady-state response indexes of the two kinds of buffer support devices are obtained.The results show that the buffer supporting device with buffer bed has better buffer effect and is not easy to resonate,so the buffer supporting device with buffer bed is used in the buffer mechanism of the transfer place.Finally,combined with discrete element technology,based on edem simulation software,this paper improves the transfer chute device.Establishes the gravel particle model according to the field data,derive the impact force formula of gravel particles on the equipment basing on the Hertz-Mindlin contact model.Then determine the chute design principle,simulate and analyze the rock and soil transfer process of the original transfer station by EDEM,then simulate the conveying process of chutes with different cavities at different conveying speeds.The average value and standard deviation of the force on the conveyor belt of the discharge arm conveyor in the simulation process are taken as the quantitative standard to evaluate the buffering capacity of different chutes at different conveying speeds.Finally,this paper determines the appropriate cavity size and conveying speed,so that the average stress value of the conveyor belt is reduced from 8588 N to 5558 N,and the standard deviation is reduced from 6539 N to4699N,which effectively reduces the rock and soil impact at the transfer position of the spreader.