Elastic wave propagation in cylindrical bars after brittle failures: Application to spalling tests

The effect of brittle failures on the elastic wave propagation along cylindrical bars is analysed. From experimental observations provided by spalling tests of ceramic materials, a theoretical analysis is carried out based on a finite elements simulation of the experiments and a mathematical analysis of the pulses by means of Fourier Transform techniques. Differences between the propagating waves before and after the material failure are revealed. After failure, the pulse is influenced by dispersion effects and its shape changes during propagation. To correct this effect, a procedure based on Bancroft's curves is suggested. Finally, some clues about the way to get consistent results from spalling tests are given.