ANALYSIS OF NONLINEAR-WAVE PROPAGATION AND SHOCK-WAVE FORMATION IN QUASI-BRITTLE MATERIAL

Fracture of quasi-brittle materials such as concrete and rocks is know n to result from the formation and development of microcracks. Microcr acks reduce the macroscopic value of Young's modulus and therefore the corresponding wave velocity, so that shock wave formation is expected . The phenomenon was studied for granite as an example of quasi-brittl e materials. By using of a constitutive law based on experiment, the n onlinear wave propagation was analyzed numerically for an infinite pla te. The plate is subjected to an impact compressive stress at one of i ts surfaces. The other surface of the plate is assumed to be stress fr ee. It was shown that the shape of the incident wave has a significant effect on the forming shock wave.