In the process of rolling and finishing, the movement track of the machining medium particles is complex and random. According to the classical mechanical model, it is impossible to accurately establish the force chain model between particles and effectively solve the problem of machining efficiency and machining uniformity of the workpiece. The discrete element software EDEM can simulate the particle processing process, which provides a good method for grasping the relative motion between particles and between particles and workpiece.
The 3D model of the barrel and spiral bevel gear is imported into the EDEM software through the intermediate format igs, and the barrel, spiral bevel gear and relative position are proportionally scaled based on the consideration of computer performance and simulation time by adjusting the coordinate and position relationship. The drum speed is N=- 50 r/min, and the workpiece speed is n=115 r/min (counterclockwise is positive). The particle is defined as spherical, with a diameter of 2 mm. The diameter of abrasive particle follows normal distribution, and its Poisson’s ratio is 0 25, shear modulus is 129 GPa, density is 4 0 × 10-9 kg/m3。 Spiral bevel gear is made of alloy steel with Poisson’s ratio of 0 3. Shear modulus is 70 GPa and density is 7 eight × 10-9 kg/m3。
200 000 particles are generated in the simulation. When 2 s is set, the barrel and the workpiece start to rotate. The particle motion in the simulation process is as shown in the figure. The overall simulation time is set to 4 s, and the time step is 0 02 s, the mesh size is 3Rmin, where Rmin is the minimum radius of abrasive particles. The contact coefficients of particles and particles, particles and spiral bevel gears are shown in the table.
| Abrasive and abrasive | Abrasive and gear | |
| Rolling friction factor | 0.15 | 0.01 |
| Static friction factor | 0.5 | 0.55 |
| Coefficient of restitution | 0.5 | 0.3 |