STUDY ON THE IMPACT-BLOCKING EFFECT BETWEEN GRINDING MEDIA AND WHEAT BRAN POWDER DURING THE VIBRATION CRUSHING PROCESS

During the vibration crushing of wheat bran, an impact-blocking effect occurred between the grinding media and wheat bran powder. Experimental results showed that the impact depth exhibited quadratic relationship with respect to particle size, while the acceleration and damping coefficients followed the order: fine powder > coarse powder > uncrushed bran > micro powder. Increasing the diameter of the grinding media enhanced the impact depth by 81.10% for uncrushed bran and by 40.41% for coarse powder, but reduced acceleration by 45.35% and 29.56%, respectively. Damping coefficients positively correlated with grinding media diameter but negatively with cylinder diameter. Material layer thickness demonstrated threshold-dependent bidirectional regulation, peaking at 40 mm, with maximum damping difference rates of 20.40% for uncrushed bran and 17.67% for coarse powder. Drop height linearly influenced the impact depth, while showing cubic relationships with both acceleration and damping. Both parameters were minimized at 500 mm. Sensitivity analysis identified grinding media diameter as the primary factor affecting damping coefficients, revealing the sensitivity hierarchy: grinding media diameter > drop height > material layer thickness > cylinder diameter. This study provided a theoretical foundation and experimental support for optimizing the vibration superfine crushing efficiency of wheat bran.