Study on dynamic characteristic and modal analysis of the large LVB4361 vibrating screen

In order to determine the vibration parameters of the large-size vibrating screens and verify their rationality, the sieve box of LVB4361 vibrating screen is taken as the object to make analysis of static, modal and harmonic response characteristics of the box of the screen. Meanwhile, field testing on both natural frequency and principle vibration mode is also conducted using the high-precision DH5922D dynamic signal testing apparatus. Finite-element analysis shows that the natural frequency corresponding to the 8th-order modal is 16.4 Hz which is closest to the working frequency(15 Hz) with a difference of 9.3% which can meet the requirements for application; the principle vibration mode of the 7—8th-order modal manifests itself in the form of leftward and rightward swing of the screen′s discharge and feed ends; at a working frequency of 15 Hz, the stress on the box is uniformly distributed with its peak value appearing on the fourth cross beam ( counted from the front end ) and on the end of the point where the fourth cross beam is connected with the side plate, with a maximum value of 57 MPa and a dynamic stress safety coefficient of 5.42, which is well below the permissible dynamic stress value; the maximum displacement of the screen box is 10.22 mm, showing a good adaptability to the amplitude of vibration; and the LVB4361 screen is proved to be rational in design. As indicated by field testing results, the measured natural frequency of the 3rd-order modality is 16.362 Hz, with a difference of only 9.08% with the working frequency of the screen box of 15 Hz, making it possible to avoid resonance during operation of the screen; the results of test on various aspects are broadly similar to those obtained through finite-element analysis, demonstrating the accuracy of the finite-element analysis, and further verifying the rationality of the design of the screen. The use of the FE analysis method and the field testing technology prove to be effective in determination of vibration parameters of the screen and their design rationality. The work made in the paper provides a technical basis for ensuring the reliability in design of large vibrating screens.