Abstract
A new corrosion monitoring technique based on the generation and propagation of highly nonlinear solitary waves in 1D granular crystals has been developed recently. In this method, a monoperiodic array of spherical particles, interacting via Hertzian contact forces, is in point contact with the structure or material to be inspected. The array is part of a wireless unit used to induce the wave in the chain and record the solitary waveform remotely. Compared to classical NDE techniques used for thickness monitoring, the developed method is low cost, portable, and simple. This study presents a numerical and an experimental investigation of the sensitivity of solitary waves to localized corrosion. In the experimental study, a corroding steel plate was monitored using solitary waves to examine the effect of corrosion in the plate on the solitary waves interacting with the plate. Furthermore, a discrete element model was coupled with a finite element model to numerically predict the effect of localized corrosion on the delay and the amplitude of the reflected solitary waves formed at the chain-plate interface. The plate was studied in both pristine and corroded conditions. Furthermore, the study investigated customizing the granular chain design to achieve solitary wave-based sensors that can be used in high-temperature environments with maximum sensitivity to corrosion. The numerical results were in good agreement with experimental results and showed that the reflected solitary waves are affected by the presence and the propagation of corrosion in the plate. It was also shown that the sensitivity of the method increases for thinner plates or when the depth of corrosion exceeds half of the plate thickness.
