B-value Based Damage Source Localization and Classification Using Acoustic Emission (AE) Data for Concrete Cylinders Wrapped with Hybrid FRCM Composites

Abstract

Structural health monitoring (SHM) of multi-component strengthening systems, such as impregnated fiber-reinforced cementitious matrix (FRCM) composites, presents significant challenges. Previous studies have focused on damage detection and classification using the acoustic emission (AE) technique. However, damage localization in such strengthened systems remains unexplored due to the varying material velocities in the fabric, pre-impregnation matrix, cementitious matrix, and concrete. This paper proposes a simplified b-value-based damage localization approach for FRCM-wrapped concrete cylinders. The study involves strengthening six concrete cylinders with pre-impregnated fabric and a spike mechanical anchorage system. Additionally, AE-based health monitoring is employed during uniaxial compression testing. The results demonstrate that mechanical anchorage and pre-impregnation improves the overall confinement capacity by about 40%–49% compared to unconfined specimens. Whereas, spatial b-value-based damage localization, implemented using a wrapped cylinder algorithm, accurately predicts severe damage locations. Furthermore, the cumulative second-order entropy trend strongly correlates with the cumulative signal strength trend, suggesting that feature-based damage detection can be considered a reliable approach.