Propagation of an acoustic pulse of finite amplitude in a granular medium

A study of propagation of a wide-band acoustic signal in a granular medium is reported. Experimental data on the propagation of pulses with an amplitude up to 3 MPa and characteristic length about 1 mu s through a sample of cobalt-manganese nodules are compared with a computer model of the process. An anomalous signal absorption in the high-frequency range observed with relatively weak sounding pulses is explained under the assumption of a fractal sample structure on a certain scale, When the signal amplitude increases, the absorption assumes a normal power form which is evidence of substance structural changes.