Dynamic characterization of elastico-mechanoluminescence towards structural health monitoring

Abstract

Light emission from zinc sulfide phosphors during elastic loading (elastico-mechanoluminescence, or EML) is characterized for application in structural health monitoring. Micron-sized EML particles are dispersed in an elastomeric matrix for characterization experiments. Numerical models and experimental investigations are combined to arrive at a correlation between EML emission intensity and average stress acting on phosphor particles. A maximum luminance of 25 cd/m2 is observed from composites with a 6.25:3 phosphor–matrix weight ratio. This intensely bright EML emission is visible under indoor lighting and is attributed to efficient interfacial stress transfer between the matrix and particles facilitated by a moisture-resistant coating. EML emission is captured over 2.5 million actuation cycles and a correlation between the structural health of the elastomer and the measured EML intensity is made. A significant drop in EML emission is observed right before the onset of structural failure which enables real-time prediction and prevention.