Acoustic emission signals resulting from the drying-induced fractures of Phyllostachys pubescens bamboo: evidence of scale free phenomena

Abstract

Acoustic Emission (AE) is a noninvasive tool for evaluation of damage and fracture. In this paper, results of AE study of the drying process of Phyllostachys pubescens bamboo are reported. The histogram of experimental squared voltage distributions follows a power law with an exponent of $$-1.16$$ . The histogram of maximum amplitudes $$V_\mathrm{max}$$ usually studied in the AE literature also shows a power law with a slope of $$-2.4$$ (b-value of 2.4). This is reminiscent of scale free phenomena. Another novel aspect for bamboo literature is the calculation of the average signal shape for different time spans of the system. The shape has an asymmetrical shape for both long- and short-span signals, but shows a symmetrical shape for middle-span signals. This is an indication of a reinforcing feedback process, known in the statistical mechanics of fracture as an avalanche.