Dynamic response of well-mixed binary particulate systems subjected to low magnitude vibration

The dynamic response of well-mixed binary mixtures subjected to low magnitude vibration was investigated using a newly developed non-invasive method. An apparent mass, defined as a ratio of the base force to base acceleration, was measured when applying a sweep vibration that ranged from 10 to 2000 Hz. The method could operate more rapidly, conveniently and non-destructively for a wider range of particle packing states, including a natural packed bed, compared to previous methods. The apparent mass data exhibited several significant peaks due to the bed harmonic resonance. The first peak frequency gave the longitudinal elastic modulus of the bed via the velocity of longitudinal stress wave propagation. For loosely packed mixture beds, the mixing fraction dependence upon the elastic modulus was found to be describable by the two-phase series model. In addition, the particle packing dependence upon the elastic modulus agreed reasonably well with the fourth power scaling law in spite of the wide size distribution. Comparison of the two-phase series model and experimental data for a range of particle packing fractions was made in terms of the coefficient of the scaling law.