Impact breakage of fertiliser granules

Systematic data are presented for the single impact failure of 3.2, 5.3, and 7.2 mm fertiliser granules over a wide range of impact speeds and angles. The probability of failure was found to change only slowly between 90° (normal) impact and 50°, but decreased rapidly below 50°. The probability of failure increased with increasing size of granules. The effect of impact velocity on the mean, median and the proportion of the largest-sized fragments were examined. Two distinct forms of normal impact damage were identified, corresponding to low and high impact velocities, and the mechanisms of failure are discussed.