Fatigue Life Analysis And Condition Monitoring Of Girth Weld Of Large Transmission Drum

Belt conveyor is the mainstream transportation device in China,which is widely used in ports,quarries,coal yards and other places.As the core component of the belt conveyor,the health of the driving drum is directly related to the normal operation of the later stage of the conveyor.The driving drum has no obvious sign before damage,and needs to be stopped for a long time to replace after damage,which has a serious impact on the conveying efficiency of belt conveyor.According to statistics,under the condition of long-term complex load,the main failure mode of transmission drum is fatigue failure,and the location of fatigue failure is mainly at the girth weld.Therefore,it is of great significance to study the fatigue life of girth weld of transmission drum to prevent the loss of transmission drum due to fatigue failure.Aiming at the problem of how to make effective fatigue life prediction and real-time monitoring of the residual fatigue life of the transmission drum,this paper takes a large transmission drum in Qingdao port as the research object and carries out the following research:Firstly,the working principle of transmission drum is established by friction transmission theory.The mechanical analysis of the driving drum is carried out,and the relationship between the pressure and the friction of the driving drum in one cycle is given.The establishment of the relationship provides a theoretical basis for the load distribution in the finite element simulation analysis of the transmission drum.Secondly,the new modeling method and the traditional modeling method are used to establish the transmission drum model respectively,and the finite element simulation results of the two models are compared through the different load loading methods,and the advantages and disadvantages of the two models are compared.The modeling and Simulation of the transmission drum with cracks in the girth weld is carried out,which provides stress data for the subsequent fatigue life prediction.Thirdly,combined with fracture mechanics theory,the fatigue life prediction formula of the transmission drum with circumferential weld crack is deduced,and the fatigue life is simulated with the nominal stress method,which is used to analyze the fatigue life of the transmission drum without circumferential weld crack.Finally,the typical fault types of girth weld and the fault identification method based on stress value are studied,and the monitoring system is designed and developed,which can monitor the stress change of transmission drum in real time and realize the functions of fault early warning,alarm and life prediction.The experiment shows that the system performance achieves the expected design goal.