WAVE-FRONT PROPAGATION IN A CLASS OF RANDOM MICROSTRUCTURES .2. NONLINEAR ELASTIC GRAINS

The propagation of stress pulses is studied in one-dimensional piecewi se constant microstructures of grains with power-law elastic response, having randomness present in constitutive moduli and grain lengths. M aterials of two types are being considered: all grains of either a sof t or a hard type. First, a Markov process is established for evolution of forward propagating disturbances, with the main feature being the progressive curving and random diffusion of the characteristics. Next, a study is conducted of the sensitivity of loading and unloading shoc k waves, as well as of washing out of pulses, to the randomness in the medium. It is found that the curving of characteristics shifts the fo rmation of a shock with respect to the classical homogeneous medium so lutions, but the strength is always decreased due to the presence of b ackscattered waves.