Failure mechanism in porous materials under compression: crackling noise in mesoporous Goethits, Corundum and SiO2
Ekhard Salje (University of Cambridge)
Slip Avalanches in Amorphous Metals
Mon 4:20 - 5:40
Barus-Holley 165
The failure mechanism of porous materials under uniaxial stress has been investigated experimentally. Microporous SiO2, Vycor, Goethite and corundum have been subjected to slowly increasing compressive uniaxial stress with stress rates between 0.2 and 12.2 kPa/s. With increasing stress the strain changes stepwise with acoustic emission correlated with each volume collapse. The acoustic emission followed the characteristics of ‘crackling noise’ with a power law distribution over an exceptionally large interval of 6 decades at the slowest stress rate. The power law exponent is -1.39 (for the energy jerk distribution) for SiO2 with low porosity and increases for all materials with increasing porosity to maximum values around -2. Possible applications in mining industry and others are discussed.