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Dynamics model on abrasive particles and workpieces during the centrifugal barrel surface finishing process was built by Discrete Element Method (DEM). The motion status of abrasive particles and workpieces was visually simulated and some important process parameters were numerically studied. The influence of planetary transmission ratio on finishing efficiency was analyzed, and finishing efficiency was the highest as the transmission ratio is −1. Finally, the conclusion was validated by experiments. Such economical and precise method could replace lots of finishing tests to optimize process parameters, which would provide theoretic basis for experimental research and efficient means for the finishing mechanism analysis of centrifugal barrel finishing.

The mechanism of granules' density variation is analyzed in concrete block vibration forming processing. The simulation of the vibrating process is done by the discrete element method analysis software - PFC2D. The change of porosity in the process of vibration of granule groups is studied and the change law is revealed. The effect of four aspects is also discussed, which are friction coefficient of granular, particle size, vibration frequency and amplitude. The porosity is positively related to friction coefficient of granular and negatively correlated to particle size. Quadric curve can be used to model the relationship between vibration amplitude and porosity. The fluctuation of change of porosity can be decreased by choosing higher vibration frequency. These research results possess a certain reference value to the design of vibration parameters and improve the quality of building block.

A jaw crusher is a kind of size reduction machine which is widely used in mineral, aggregates and metallurgy fields. The performance of jaw crusher is mainly determined by the kinetic characteristic of the liner during the crushing process. The practical kinetic characteristic of the liners which are located in certain domain of the coupler plane are computed and discussed. Based on those computing results and analysis for the points chosen from the liners paralleling coupler plane, unique swing features and kinematics arguments are determined in order to build the kinetic characteristic arguments. The job is helpful for a design of new prototype of this kind of machine on optimizing the frame, designing the chamber and recognizing the crushing character.

The fluid magnetic abrasives (FMA) are a new kind of precision finishing abrasives. In the absence of an applied magnetic field, FMA exhibit Newtonian-like behaviour. When exposed to a magnetic field, the viscosity and yield shearing stress of FMA increase several orders of magnitude rapidly, a reversible fluid-to-solid phase transition occurs, and a "soft abrasive layer" in conformity to the profile of work surface is created. Based on these distinctive features of FMA, a new type of precision finishing technology for complex geometrical shapes of engineering components has been developed. In this paper, the finishing mechanism, finishing process and applications of FMA are presented. Based on the yield shearing stress model of the FMA and the theory of fluid dynamics, The mathematic model of cutting force acted on the surface and the equation of material removal rate have been derived. The influence of some key parameters such as magnetic strength and direction, size of abrasives, volume concentrations of nonmagnetic abrasive and ferromagnetic particles, saturate magnetization, time of process and relative motion speed in respect to work pieces in finishing process on the finishing efficiency and the final surface roughness are discussed as well.