2004 Volume 53 Issue 10 Pages 489-494
Fracture dynamics of atmospheric rusts were studied by Lamb-wave acoustic emission (AE) analysis. Fracture parameters of the rust were estimated by the waveform matching of the S0-mode packet of Lamb AEs monitored during tensile- and compressive-bending of steel plates with atmospheric rust produced by out-door exposure for 500 days. Generation times of rust fractures are estimated to be less than 1μs, however, the crack volumes are several hundred to thousand times larger those of the delayed fractures. Next we monitored water-born longitudinal AEs from rust fracture on the bottom plate of the water-storage cylindrical tanks using the sensors mounted on the side-wall, and estimated their source locations. AEs were monitored by the AE system with 20dB amplification, however, their source location accuracy was poor due to the low S/N ratio.