In a previous post we already reported about acoustic emission experiments on cellular glass. The experiments are described in a public scientific paper. This paper was in the mean time 96 times cited, which is a nice result. Indeed, people found the same phenomena in the crumbling of paper, in bundles of glass fibres, in theoretical simulations and in earthquakes. The citations can be found here with GOOGLE SCHOLAR. This service is invented to satisfy the ego of scientists, also mine. Like can be observed, even in 2014 after more than 15 years, the paper is still cited and this year, an important paper was found by the system.
The paper describes tensile experiments monitored with acoustic emission on polyurethane foams. They found the following similarities:
- power law distribution for the magnitudes of the events
- Power law distribution for the time between events
- almost no dependence on the density
The second power law is not present at lower temperatures, which is unexpected. At lower temperature where the foam is brittle, I would expect even more similarities.
But the paper focuses on the fact that cellular structures fail in a different way than the base material, explaining why a seriously reduced safety factor can be used. In cellular glass, this is an important property when we think about cellular glass under buildings, under large tanks with liquid gas and the intelligent GLAPOR® solution under buildings with boards and gravel.