The Influence of Global Corrosion Degradation on Localized Damage Detection Using Guided Waves

Beata Zima; Emil Roch; Jochen Moll

doi:10.1007/978-3-031-49413-0_77

The Influence of Global Corrosion Degradation on Localized Damage Detection Using Guided Waves

Abstract

This paper presents the results of a numerical analysis of the influence of corrosion degradation of metal plates on the wave propagation phenomenon. There are several different corrosion types, but general and pitting corrosion are the most common. General corrosion is more or less uniformly distributed over the entire exposed surface of the metal while pitting corrosion takes the form of localized cracks. Because the general corrosion is related to thickness reduction and in consequence, wave propagation velocity, this study is focused on the influence of the variable thickness of corroded plate described by the statistical descriptors (average thickness, standard deviation and coefficient of variation) on the uncertainty of localized damage detection based on the algorithms incorporating velocity of the guided wave. Numerical simulations were conducted for corroded plates with localized cut-through damage. The irregular surface of the plates was modeled using random fields. In this study, the plates varying in degree of degradation (DoD) as well as in geometry of the surface have been analyzed. Such an approach allowed for observing the effects of both thickness reduction and the exact geometry of corroded plates on damage detection and localization. The common approach based on delay and sum algorithm to detect and localize damage has been applied here.