Research On Structural Damage Diagnosis And Fatigue Life Prediction Of Large Vibrating Screen

In this paper,27m~2linear vibrating screen was taken as the research object.we apply the structural damage identification and fatigue life prediction method of large linear vibrating screen.The finite element model of large linear vibrating screen was built to know the displacement and strain modal parameters analysis of the structure of the vibrating screen.The strain mode change rate and the modal strain energy change rate can be used as the damage index of the side plate of the vibrating screen to study damage Identification analysis.study on the sensor placement for the vibrating screen upper beams to realize real-time damage monitoring.By using the critical plane method,fatigue life is analyzed for the multi-axis fatigue damage model of the large linear vibrating and spandrel girder.Firstly,this paper introduced the working principle and general structure of large linear vibration,using the working principle and performance characteristics of the large linear vibrating screen itself to designs and selects the key kinematics and dynamic parameters of the large linear vibrating screen.The mechanical model and the centroid trajectory equation of the large linear vibrating screen are established such as the shaft-block eccentric exciter,under beam and side pane are carried out,and building the27m~2linear vibrating screen model of the circular vibrating screen by 3D modeling software.Secondly,using ANSYS WORKBENCH finite element model software to comprehensively research modal analysis of the linear vibrating screen.In order to improve the structure mechanical properties and service life,which the resonance phenomenon of the large linear vibrating screen will not happen.The beam structure of the vibrating screen is optimized,comparing and analyze the before and after of the structural improvement of the natural frequency and natural mode.Meanwhile using ANAYS software analyze the real damage of the plate where there is extremely fragile through decrease its element thickness.Thus a indicator is defined by using the strain modal variable ratio and the strain energy modal variable ratio,which have mutation peaks at the location of the fatigue damage,furthermore,providing the reference alarm for damage identification of the vibrating screen.Thirdly,the local fatigue safety factor of the crossbeam is low,this should study on the sensor placement in order to know the real-time monitoring of damage.Studying on the measurement points of sensor placement,which are building the modal strain value,selection criteria for the measure placement and adopting the reasonable methods to select the sensor measurement points.The paper proposed a genetic clustering and simulated annealing algorithm g method algorithm to optimal measurement points of sensor placement by the D-value of the modal strain between the intact and damaged beam.The cluster analysis visual display all sensor measure points and more accurately find the global and most optimal result.In the end,using the critical plane method to analyze multiaxial fatigue life and using FESAFE software to analyze fatigue life reliability,the logarithm fatigue life nephogram of the vibrating screen and the spandrel girder are obtained.The results show that the large vibrating screen is a high service life and fatigue reliability.