Research on the Discrimination of Acoustic Emission Signal Transmission Modes for Void Damage in Concrete‐Filled Steel Tubes

ABSTRACT Concrete‐filled steel tubes (CFST) have been extensively employed in large‐scale construction projects as high‐performance composite structural members. Nevertheless, varying degrees of void damage frequently occur in CFST due to construction quality issues and environmental influences, which may potentially result in serious structural failures. This study proposes a method for detecting void damage in steel reinforced concrete using acoustic emission (AE) technology. AE testing was used to detect void damage in CFST, and the effects of different void rates and specimen sizes on AE signal characteristics were studied and explored. By conducting AE experiments and employing the first‐wave arrival time parameter for signal analysis, four theoretical transmission modes of steel‐concrete interface signals under void damage conditions were successfully identified. The experimental results showed that the void area significantly changed the propagation path of sound waves. By using signal conformity testing parameters to calculate and compare the predicted duration and measured duration of three theoretical modes in the void area, the final agreement between the average experimental duration and the theoretical duration of Path 2 was 87.41%. Considering the heterogeneity of concrete and the errors present in experiments, and that the increasing trend of test duration is consistent with theoretical values, this verifies the effectiveness of acoustic emission technology in damage identification and structural health monitoring.