Simulation of the vibration screen operation in resonance mode
Received 19.05.2021, Revised 10.10.2021, Accepted 19.11.2021, Published 17.12.2021
Abstract
To investigate excitation of two-frequency resonant vibrations of the screen box by passive autobalancers. An upgraded inertial screen with a ball autobalancer as a vibrating exciter was simulated, which creates two-frequency resonant vibrations. The basic parameters influencing the stability of two-frequency resonant vibrations was identified. The existence of two-frequency resonant vibrations has large limits and allows to change the characteristics of two-frequency resonant vibrations by changing many parameters. A positive effect from the replacement of the inertial vibrator with a two-frequency resonant was obtained. Research methods are as follows: Solidworks CAD program to create a simulation model, and a Cosmos Motion module to simulate the dynamics of a vibrating machine. The obtained data were processed in the computer algebra system Mathcad. The change areas of the basic parameters providing fast and guaranteed approach of two-frequency resonant vibrations are defined. Assumptions about the operation of the mechanism of two-frequency resonant vibrations are formulated and tested. The advantages of a resonant vibrating machine with a two-frequency vibrating exciter enables to get an energy-efficient machine of high productivity. The simulation technique implemented for vibrating screens can be used for other vibrating machines. In the developed model, which has identical geometric, mass-inertial parameters and fully corresponds to the natural screen, under changes in system parameters are guaranteed to occur two-frequency resonant vibrations. These parameters include box's weight, corrective load weight, unbalance weight, unbalance speed, stiffness of supports and viscous resistance forces. Increasing the weight of the box reduces the lower frequency of oscillations. The corrective loads are automatically adjusted to change of a box's weight. Increasing the mass of corrective loads directly proportionally increases the amplitude of slow oscillations of the box. Increasing the mass of unbalance in the body of the autobalancer directly proportionally increases the amplitude of rapid oscillations of the box. Increasing the speed of the rotor directly proportionally increases the speed of rapid oscillations of the box. Parameters influencing the amplitude of slow oscillations were determined.
Keywords:
resonance; two-frequency vibration exciter; unbalance; autobalancer; screen; modeling
