Acoustic-structure interaction-based identification for subsurface voids in steel-concrete composite structure: Experimental study and numerical simulation

Abstract

Steel-concrete composite structure (SCCS) has gained wide application in infrastructures for its excellent mechanical properties and reasonable economy, the structural integrity and service performance of which, however, are threatened by interfacial defects between steel and concrete. The detection methods focusing on vibration characteristics have demonstrated preferable effectiveness in detecting subsurface voids in SCCS compared to other non-destructive testing methods. This study provides a comprehensive understanding of the impact response (IR) method for detection in this regard, integrating theoretical analysis, experimental study, and multi-physics coupled numerical simulation with particular emphasis on considering acoustic-structure interaction. This coupling effect is confirmed to correlate with three-dimensional sizes of void defects, facilitating the identification of subsurface voids. A specimen is specially designed and subjected to IR tests to furnish results for experimental validation. The simulation results reveal frequency-splitting phenomena and distinct distributions of acoustic fields inside voids, which are attributed to acoustic-structure interaction. Noteworthy influences of void depth on the vibration characteristics of the structure are also highlighted, including apparent frequency deviation and redistribution of damping effect in modal analysis, as well as beat phenomena in transient analysis. Moreover, the identification of subsurface voids along with their depth is attained in practice by the proposed data analysis strategy based on attenuation characteristics of vibration response and waveform fitting. The findings of this study also underscore the significance of considering acoustic-structure interaction when analyzing vibration characteristics during interfacial defect detection in SCCS.