Acoustic Emission Enabled Particle Size Estimation via Low Stress-Varied Axial Interface Shearing

Abstract

Acoustic emission (AE) refers to a rapid release of localized stress energy that propagates as a transient elastic wave and is typically used in geotechnical applications to study stick-slip during shearing, and breakage and fracture of particles. This article develops a novel method of estimating the particle size, an important characteristic of granular materials, using axial interface shearing-induced AE signals. Specifically, a test setup that enables axial interface shearing between a one-dimensional compression granular deposit and a smooth shaft surface is developed. The interface sliding speed (up to 3mm/s), the compression stress (0-135kPa), and the particle size (150μm-5mm) are varied to test the acoustic response. The start and end moments of a shearing motion, between which a burst of AE data is produced, are identified through the variation of the AE count rates, before key parameters can be extracted from the bursts of interests. Linear regression models are then built to correlate the AE parameters with particle size, where a comprehensive evaluation and comparison in terms of estimation errors is performed. For granular samples with a single size, it is found that both the AE energy related parameters and AE counts, obtained using an appropriate threshold voltage, are effective in differentiating the particle size, exhibiting low fitting errors. The value of this technique lies in its potential application to field testing, for example as an add-on to cone penetration test systems and to enable in-situ characterization of geological deposits.

A denoising method for acoustic emission signals based on discrete wavelet transform in WEDM

“…Wire electrical discharge machining (WEDM), with its advantages of processing high-hardness materials and achieving high precision, holds a significant role in the manufacturing industry [1]. Acoustic emission (AE) signal refers to the transient elastic waves generated by the rapid release of energy from a localized source within a material [2]. AE testing technology, as a nondestructive testing technique [3], has been applied to WEDM in recent years.…”

Dynamic Rail Near-Surface Inspection of Multiphysical Coupled Electromagnetic and Thermography Sensing System

“…UT is good at evaluating deep defects in rail web and has a high degree of automation, however, it is not easy to inspect specimens with complex geometry shapes and is inseparable from various couplants [6] [7]. AET provides an opportunity for real-time online monitoring of rail cracks propagation, worryingly, it has extremely high requirements of signal noise suppression [8] [9]. VT has the advantages of simple operation, low cost, intuitive display, and superhigh resolution for opening cracks, whereas the fault inspection relies on a clean background which is easily broken by the heterogeneous geometric structure of rails [10] [11].…”