Analysis Of Harrow Teeth Wear Of QS-650 Screen Cleaning Machine Based On Dynamics Co-simulation

With the rapid development of China's railway construction,more and more attention has been paid to further improve the safe operation of the railway.The quality of the track bed is one of the key factors affecting the efficiency and stability of railway transportation.When the pollution of the track bed reaches a certain level,the track bed will harden and reduce the train ride stability.In order to prevent the phenomenon of track bed hardening,it is necessary to screen the track bed regularly.The excavating chain of ballast cleaning machine is the main excavating device of ballast cleaning machine.In the process of excavation,the rake tooth of the excavating chain are worn by the impact and friction of ballast.The continuous wear of rake tooth will make the excavating chain invalid and affect the mining efficiency of the ballast cleaning machine.By simulating the ballast-digging process of the ballast cleaning machine,the wear depth of the rake tooth is calculated,which can provide reference value and theoretical basis for the research and improvement of the structure of the rake tooth.In this paper,the excavation system of QS-650 type full-section ballast cleaning machine is taken as the research object.Under the condition of general track bed excavation,the wear depth of rake tooth in the process of excavation is analyzed and studied by means of dynamic joint simulation.The main work can be summarized as follows:(1)The finite element simulation flow for calculating rake tooth wear is introduced based on the idea of dynamic joint simulation.The kinematics software SIMPACK was used to analyze the kinematics analysis of the excavating chain drive system.The kinematics model of excavating chain transmission system is established by simplifying guide groove and excavating chain.The whole chain of the excavating chain is tensioned and the driving sprocket is driven to make the chain move at a linear speed of 3.2m/s.By setting the sensor in SIMPACK,the velocity time curve of the rake tooth's pin hole position in the horizontal mining process is output.(2)Based on ARCHARD wear model,the formula for calculating the wear depth of rake tooth is derived.The wear depth of rake tooth in the process of digging ballast is mainly related to the stress of rake tooth.By integrating the stress time curve of the tooth tip,the wear condition of the tooth tip can be obtained.In the LS-DYNA module of HYPERMESH,finite element modeling is carried out for the ballast-digging process of rake tooth.In the finite element model,the velocity time curve at the pin hole obtained by motion analysis is loaded on to the chain pin by means of velocity boundary loading.Simulation of two rake teeth digging ballast process,output rake tooth tip part of the unit stress time curve.The wear depth of rake teeth in single excavation process was obtained by integrating the stress time curve of tooth tip.(3)The theoretical excavation resistance of rake tooth is calculated.The stress distribution of the rake tooth is analyzed under the action of drag force.The stress time curve of the tooth tip element under the theoretical mining resistance is obtained by simulating the mining process of the rake tooth under the theoretical mining resistance.By integrating the stress time curve of the rake tooth tip,the wear depth of the rake tooth under the theoretical mining resistance is obtained,and the feasibility of the ballast-digging model of the rake tooth is verified.