Analysis of contact force characteristics of vibratory finishing within pipe-cavity

Vibratory finishing realizes the finishing of the workpiece surface by vibrationally-fluidized granular media. Due to the granular media’s fluidized nature, vibratory finishing can be applied to surface finishing in restricted space, such as the cavity of integral casting casing. In this work, taking the typical elongated pipe-cavity inside the casings as the analysis object, based on the discrete element method (DEM), a series of simulations were carried out on the length and diameter of pipe-cavity, the load of media, vibration amplitude, and frequency. The frequency multiplication of the normal contact force between the granular media and the surface in restricted space was discovered. A method of processing contact force data based on the Fourier transform was proposed. And then, the normal contact force, its average, and coefficient of variation at different positions of the slender pipe-cavity were analyzed. It is found that the normal force fluctuates along the axial direction and is symmetric on the circumferential positions. Furthermore, the effects of various variables, including length, diameter, load, amplitude, and frequency on the normal force, have been obtained. The method and results can reference studying the dynamic behavior of granular media in restricted space.