Experimental Research And Finite Element Analysis Of Large Vibrated Fluidized Bed Beam Fatigue Fracture

Vibrated fluidized bed is widely used in mining,coal,petroleum and chemical industry etc.However,the bed has to bear a large alternating excitation force at high vibration frequency,so it often appears fatigue damage such as cracking of the beam in practical work.Especially,fatigue damage in the large vibrated fluidized bed is becoming more severe.Because the fatigue failure of the beam often does not appear obvious plastic deformation,the destruction is very sudden.So study on fatigue fracture of the beam to improve the reliability of the products is very important.In this paper,GH4169 alloy using in large vibrated fluidized bed is selected as the research subject,the fatigue crack propagation tests at different stress ratio are carried out in air at room temperature.The fatigue crack initiation about GH4169 alloy at different notch radiuses and stress ratios is analyzed by fracture mechanics.The results reveal that,the fatigue crack initiation life can be well predicted by the fatigue initiation life curve characterized by the parameter ?KI/(?).There is a fatigue initiation threshold on the theoretical curves at different notch radius which is similar with the S-N curve.At different stress ratios,there is a critical value for the parameter ?KI/(?).When the control parameter is less than the critical value,the fatigue initiation life increased with increasing of stress ratio.Otherwise,the fatigue initiation life decreased with increasing of stress ratio.It is shown from the regression analysis by Paris formula that the crack growth rate increases with increasing stress intensity factor and stress ratio,the modified Paris formula considering threshold value can state the law of the fatigue crack growth at relative small stress intensity factor range,and the general representation with fracture toughness can describe the fatigue crack growth behavior accurately.By using ANSYS obtained the dangerous position of beam.With modern fatigue theory as a foundation,analysis the destruction causes of beam,determine the applicable method of fatigue life analysis of vibrated fluidized bed bearn.Calculate and predict the fatigue life of beam without manufacturing defects in approximate actual situation.In addition,residual life of crackled beam is estimation adopted linear-elastic fracture mechanics method,calculated and drawn the curve of crack length and residual life of beam,gained crack propagation law.Provide scientific methods for fatigue life prediction of vibrating screen beam.This paper illustrated the proposed method has important practical value,provides important theoretical basis for the vibrated fluidized bed beam safely operation and repair.It is significant for prolonging the life of the vibrated fluidized bed and improving the production efficiency of the vibrating fluidized bed in the production activity.