Stochastic analysis on modal frequency of linear vibrating screen

Stochastic factors inevitably exist in the process of vibrating screen manufacture and installation. Based on stochastic structure model, the stochastic modal analysis was made, the statistical description of modal frequency variability was given, and the effects of stochastic parameters(elastic modulus, density of the rubber spring or steel)to vibrating screen modal frequencies were discussed. The results showed that, in a sense of first-moment, stochastic rubber spring elastic modulus had important influence on the mean value of the first three frequencies for vibrating screen, stochastic steel density had a greater effect on mean value of high-order frequencies. In a sense of second-moment, the mean value dynamic deviation of the first three frequencies was larger which caused by stochastic variation coefficient of rubber spring elastic modulus. The mean value dynamic deviation of high-order frequencies was larger, caused by stochastic variation coefficients of steel elastic modulus or density. Stochastic rubber spring density had little effect on the modal frequencies. Analyzing sensitive parameters to modal frequency variation coefficient, it drew a conclusion that the variation coefficient of rubber spring elastic modulus was the most sensitive parameter to relative mean value deviation coefficient and variation coefficient of the lower orders frequencies, the variation coefficient of steel elastic modulus was the most sensitive parameter to variation coefficient of the high-order frequencies, and the variation coefficient of steel density was the most sensitive parameter to relative mean value deviation coefficient of the high-order frequencies.