Acoustic emission detection and modal decomposition using a relaxor ferroelectric single crystal linear array.

This paper reports on an acoustic emission (AE) sensor based on relaxor ferroelectric single crystal (RFSC) transduction. The sensor crystal is arranged into a Linear Array for Modal Decomposition and Analysis (LAMDA), with the sensor interrogated by a bespoke high-bandwidth instrument. The efficacy of RFSC LAMDA sensors is showcased through a series of comparative experiments, which include the simultaneous acquisition of pencil lead break (PLB) AEs in a 1.

Modal Decomposition of Acoustic Emissions from Pencil-Lead Breaks in an Isotropic Thin Plate.

Acoustic emission (AE) testing and Lamb wave inspection techniques have been widely used in non-destructive testing and structural health monitoring. For thin plates, the AEs arising from structural defect development (e.g.

Detection of Defects in Geomembranes Using Quasi-Active Infrared Thermography.

High-density polyethylene geomembranes are employed as covers for the sewage treatment lagoons at Melbourne Water Corporation's Western Treatment Plant, to harvest the biogas produced during anaerobic degradation, which is then used to generate electricity. Due to its size, inspecting the cover for defects, particularly subsurface defects, can be challenging, as well as the potential for the underside of the membrane to come into contact with different substrates, viz. liquid sewage, scum (consolidated solid matter), and biogas.

Determination of the in-plane components of motion in a Lamb wave from single-axis laser vibrometry.

A method is proposed for determining in-plane components of motion in a Lamb wave from laser vibrometer measurements of surface motion out of plane. The approach relies on a frequency domain transformation that assumes knowledge only of the plate thickness and the bulk wave speeds. An outline of the relevant theory is followed by several validation case studies that generally affirm a useful level of accuracy and robust performance across a relatively wide frequency-thickness product range.