Research on nonlinear dynamic characteristics of double-deck vibrating flip-flow screen

Abstract The double-deck vibrating flip-flow screen is taken as the study case, and the dynamic equations, including cubic nonlinear stiffness, are established. The equation in the physical coordinates is transferred to the modal coordinates to study the nonlinear vibration characteristics of the system in resonance, which is analyzed by the multi-scale method. Then, the amplitude-frequency tuning parameter response equation is obtained. The influence of system parameters on the nonlinear system is discussed by solving the amplitude-frequency tuning parameter response equation. It is found that increasing the damping or reducing the harmonic force will suppress the system’s multiple solutions and vibration jumps. Numerical methods are adopted to verify the accuracy of the perturbed solution in both the frequency domain and time domain. Considering that the nonlinear stiffness has little influence in the slightly distant single-valued response resonance region, the displacement response of the double-deck vibrating flip-flow screen in the original physical coordinates system is obtained based on the superposition principle. The amplitude of the main screen frame is 7 mm, and the amplitude of the upper and lower floating frame is 9.4 mm and 5.6 mm, respectively. The phase between the main screen frame and the upper and lower floating frame is 180°, which realizes the stretching and slackening of the deck. This paper guides the design of double-deck vibrating flip-flow screens.