1983 Volume 47 Issue 7 Pages 575-581
A simulation of acoustic emission signals due to fracture events was carried out in order to investigate the temporal inhomogeneity of fracture processes. In the simulation process, two types of source function D(t), the product of crack volume-time history and elastic modulus, were assumed, and output signals from piezoelectric transducer V(t) were calculated from the convolution of D(t) with R(t), which is a combined response function of specimen and transducer obtained experimentally by the use of breaking pencil lead. It was shown that the amplitude of V(t) was proportional to the crack volume and the longer the lifetime of cracking, the smaller the amplitude. From these results, it was proved that only the fracture events with large cracking volume and short lifetime were detectable as an acoustic emission and that burst type emissions during macroscopic subcritical crack growth were attributed to the instantaneous fast fracture in the microscopic sense.
