Experimental and numerical identification of corrosion degradation of ageing structural components

The study presents experimental and numerical identification of corrosion degradation of thin-walled structural components employing guided wave propagation. The steel structural components are subjected to through-thickness varying corrosion degradation levels. The developed approach using the non-destructive guided wave-propagation quantifies the equivalent average corrosion degradation level by exploring a limited number of transducers. A group velocity dispersion curve reconstruction has been used to determine the corrosion-induced plate thickness reduction. Two case studies are used to examine experimentally the newly developed approach. In the first one, the dispersion curve and the assessment of the corrosion thickness reduction have been made using wave signals of various excitation frequencies. In the second one, the analysis was conducted only for two wave propagation signals and one excitation frequency which allowed for reconstructing the dispersion curve in a limited frequency range. A good agreement between the natural and estimated corrosion degradation levels was observed in both case studies. The present study develops a signal processing methodology, which can be used in the SHM systems. Several aspects still need to be further investigated before the developed approach can be applied to the complex ship hull structures' large size and complex geometry.