Dynamic Characteristics of Vibrating Flip‐Flow Screens Considering Material Impact Force

ABSTRACT Vibrating flip‐flow screens are widely used in the field of screening; its actual operation is affected by the impact force of materials, but existing research usually ignores this effect. Based on this background, considering the influence of material impact force and moment on vibrating flip‐flow screens, this paper develops a dynamic model and a vibration differential equation of a vibrating flip‐flow screen, performs the analysis of material movement and calculation of the material impact force, and includes the material impact force in the dynamic characteristic analysis of a vibrating flip‐flow screen. The results indicate the following: (1) The impact forces and account for 29% and 57.58% of the excitation force amplitude, respectively, indicating that they are of the same magnitude as the excitation force. Material impact increases the vibration amplitudes of the main and floating frames, and therefore, cannot be ignored in vibrating flip‐flow screen design. (2) By comparing the vibrating flip‐flow screen's responses with and without the impact, it is found that impact force significantly influences the system response, causing the displacement curve to shift and the amplitude–frequency curve to have periodic fluctuations and peak values. (3) The effects of impact parameters on the dynamic characteristics of a vibrating flip‐flow screen are studied. The results show that increases in material mass and material binding coefficient lead to a decrease in the system natural frequencies. Due to the impact force, the amplitude–frequency curve of the main frame peaks at a frequency lower than the first order of the natural frequency, and the amplitude–frequency curve of the floating frame peaks in the intervals of 5–10 Hz and 20–25 Hz. The results provide a theoretical reference for the design of vibrating flip‐flow screens. The operating frequency of vibrating flip‐flow screens should be selected to avoid the peak value due to the impact force, which helps extend the working life.