Analysis of acoustic emission characteristics of ice under three point bending

Abstract

Acoustic emission (AE) is one of the promising techniques to understand the damage mechanism within a material and structural health monitoring non-invasively. The transient elastic energy released during the microscopic failure within a material is termed as acoustic emission. AE signals carry information about the mechanism and intensity of damage within a material. In this study, AE signatures were recorded during the mechanical loading of notched ice beams subjected to three point bending tests at three different strain rates i.e. 1 × 10−5 s−1, 1 × 10−4 s−1 and 1 × 10−3 s−1. Various AE characteristics such as hits, amplitude, counts, rise time, energy release rate etc. were analysed in relation to the loading behaviour of ice beams. The AE amplitude distribution data was analysed to estimate b-value and its temporal variation throughout loading for all the three strain rate experiments. A decreasing trend in b-value with increasing bending stress was observed in all the three tests. Characterization of dominant failure mode was also attempted through the analysis of RA parameter and average frequency (AF) which indicates tensile mode as the dominant mode of fracture during three-point bending.