With the development of screening technology, rotary vibration screen has been widely used in the field of screening, due to its advantages of high efficiency, low consumption, clean screening environment and so on. Here, we report a simulation study to explore the influencing factors of the screening rate of ultrasonic rotary vibrating screen, basing on DEM. Firstly, the effects of vibration frequency and vibration amplitude on the screening rate of ordinary rotary vibration screen were studied, with the optimal parameters to be obtained. Then, the effects of vibration frequency, vibration amplitude and ultrasonic amplitude on the screening rate were studied through orthogonal test. Accordingly, the optimal parameters were determined, which are vibration frequency 12 Hz, vibration amplitude 1.5 mm and ultrasonic amplitude 15 μm. The influence degree of parameters on screening rate is in order of vibration frequency, vibration amplitude and ultrasonic amplitude. With ultrasonic vibration has a strong in effect in dispersing the aggregate of material particles, solving the problem of hole blocking on the screen surface and increasing the screening rate.

Ceramic materials are widely used in all walks of life, because of their excellent thermal stability, insulation and wear resistance. However, there are still drawbacks in machining process of ceramic materials, such as low production rate and poor processing accuracy. Therefore, grinding method and equipment are urgently needed to meet the current demand. Rotary ultrasonic assisted machining is an advanced technology to solve the above problems. However, in the design of the equipment, it is easy to ignore the dimensions of the groove of the front cover, the chamfer of the rear cover and the position of the tool head. Accordingly, the vibration frequency and amplitude of the rotary ultrasonic-vibration system would be affected, resulting in poor processing efficiency. Under the Newton’s law, the external dimensions of rotary ultrasonic-vibration system are designed, while the variation rules of the dimension parameters of front cover plate and the rear cover plate and tool head on rotary ultrasonic-vibration characteristics are analyzed by using finite element method. When the distance of the tool head is 6 mm, the groove width of the front cover is 14 mm and the back cover is not chamfered, the frequency of the rotary ultrasonic-vibration system is 20.5 kHz, while the amplitude at the end of the tool head is 21.346 μm and the machining performance is optimal.

In order to reduce the impact of screen surface blockage on screening efficiency during the screening process, the screening process of a rotary vibrating screen was simulated based on the discrete element method. Firstly, a three-dimensional model was established to study the effects of particle shape, vibration frequency, vibration amplitude, and the introduction of ultrasonic vibration on screen surface blockage. The optimal parameters were analyzed and determined according to the relationship between parameters and plugging rate and screen penetration rate. Secondly, ultrasonic vibration was introduced. It is experimentally shown that ultrasound can be used to remove particles that are clogged in the sieve pores, thus effectively reducing the blockage of the sieve surface while ensuring a high screen penetration rate. Finally, by combining the simulation data and experimental verification, optimal combination parameters for improving screen blockage were obtained. The particle shape is a sphere, the vibration frequency is 12 Hz, the vibration amplitude is 2.5 mm as the optimal parameters, the hole plugging rate is sufficiently low and the high screening rate is guaranteed. Meanwhile, the introduction of ultrasonic vibration effectively reduces the clogging rate of the sieve holes and hence improves the clogging situation of the sieve surface.