Single Particle Crushing by the Double Pendulum Type Impact Testing Apparatus

Abstract

Impact crushing of single particles made of eight kinds of brittle materials was carried out by using an impact testing apparatus composed of a double pendulum. Specimens were shaped into spheres having a nominal diameter of 2.0 cm.
The experimental results are summarized as follows : 1) Specific fracture energies were found to be less than those calculated from the equation derived by applying the Hertz theory. 2) The experimental relationship between impulse and specific fracture energy for the glassy materials was found to be in agreement with the theoretical one. For the minerals, however, the experimental values of impulse were found to be greater than the values calculated from the theoretical equation. 3) New surface produced could be calculated by three parameters consisting of the Gaudin-Meloy-Harris (G-M-H) size distribution equation. These parameters were found to be also represented as the function of impact energy. 4) The energy law was found to be similar to the final fineness limit theory proposed by T. Tanaka. 5) The crushing efficiency under impact loading was found to be better than that under static loading for gypsum, but both efficiencies were found to be nearly equal for the other kinds of samples.