Research On Dynamic Characteristics And Fatigue Life Of Armoured Face Conveyor Chain Transmission System

The armoured face conveyor(AFC)is the only transportation equipment for the fully mechanized coal face.The chain drive system is the main subsystem of the AFC.The stability and reliability of the chain drive system are directly related to the safety of the AFC and even affect the entire coal mine.Impact load and chain blocked have a significant impact on the stable running of the scraper chain and the fatigue life of the sprocket and link.Therefore,it is necessary to study the dynamic characteristics of the chain drive system.This is also important for improving operational reliability and fatigue life.In this dissertation,the mechanical mathematical model of the round link chain drive system in an AFC is firstly analyzed.The running resistance,traction force and pre-tightening force of the round link chain are analyzed based on the distribution characteristics of coal materials.The meshing process with the sprocket is divided into periodic meshing process,and the mechanical analysis of the three meshing stages is carried out.The contact process of the circular chain is analyzed by the symmetric penalty function method,which lays a theoretical foundation for the subsequent dynamic characteristics simulation analysis.The meshing process of the link and the sprocket is periodic,and the mechanical analysis of the three meshing stages is carried out.The contact process of the round link chain is analyzed by the symmetric penalty function method,which provides a theoretical basis for the subsequent analysis of dynamic characteristics.The simulation model of the round link chain drive system is established in the simulation software ADAMS based on the multi-body dynamics theory,In order to verify the correctness of the simulation model,a AFC dynamic characteristics test bench is built to collect the sprocket speed and scraper acceleration and the simulation results are consistent with the experimental data to some extent.It shows the validity and rationality of the simulation model and simulation method.The dynamic characteristics of the chain drive system under impact load,chain blocked and chain broken are obtained through the simulation of ADAMS software.The finite element model of the chain drive system is established by the nonlinear dynamics finite element software ANSYS/LS-DYNA with the parameterized design language APDL.The contact analysis of the chain ring and sprocket meshing transmission process is carried out,and the meshing contact and friction of the round link chain under the tension force are simulated.The influence of the chain tension on the contact dynamics is analyzed.The stress distribution law and meshing friction of the round link chain are obtained.The stress time courses of the sprocket and link dangerous position under different working conditions is extracted with the finite element simulation results.The fatigue life analysis software nCode DesignLife is used to carry out the load rain-flow counting.The sprocket and link material S-N are estimated based on the experimental data.The linear fatigue damage accumulation rule is selected to calculate the sprocket and link fatigue life,and finally the Stress Life module is used to analyze the fatigue life sensitivity in order to obtain the influence of different input parameters on the fatigue life.It is helpful to find out the round link chain drive system fatigue life weakness in the early stage,which is of great significance for the safety production in fully mechanized coal face.