Acoustic mechanism and characteristics of corrosion bubble rupture

Abstract

Bubble rupture is one of the main acoustic emission (AE) sources for corrosion detection and the study of its acoustic characteristics is of great significance for corrosion identification. However, the stress state affects the form of bubble rupture, causing different acoustic characteristics. In this paper, the acoustic signal characteristics of two forms of bubble rupture and drag phenomena are investigated and the process of bubble rupture both near to and away from the metal surface is studied, mainly through theoretical calculation, numerical simulation and experimentation. A theoretical model of bubble rupture is established according to the volume of fluid (VOF) method. The finite element method is used to solve the plate displacement at the interface. Stress pulse theory is applied to calculate the AE signal amplitude of the bubble rupture. AE source characteristic parameters of the bubble rupture are then proposed. The experimental results demonstrate that the two forms of characteristics of the AE signals from corrosion bubble rupture are consistent with theoretical calculation and simulation results.