Acoustic emission multi-parameter characterization of seismic damage evolution for different double skin composite shear walls

Double skin composite (DSC) shear walls have recently gained increasing attention as an emerging structural system for high-rise buildings; however, their seismic damage evolution and performance degradation mechanisms under earthquake excitations remain insufficiently understood. This study comparatively investigates conventional and enhanced DSC shear walls through acoustic emission (AE) monitoring and proposes a multi-parameter framework for damage characterization and damage-state assessment. Results show that geometric asymmetry induces pronounced asymmetric hysteretic responses. Failure evolves from buckling of steel-concrete columns to core concrete crushing and final tensile fracture of steel plates, indicating a progressive ductile-to-brittle transition. AE features reveal a clear transition from dispersed minor damage to localized severe damage in different DSC shear walls. Strong correlations among energy-related parameters indicate consistent AE intensity responses during damage development. Peak frequency, historical index (HI), and severity value (S r ) and normalized AE activity indicate that the web wall makes a greater contribution to global damage accumulation, with failure concentrated near its base. RA-AF analysis indicates a dominant tensile-cracking tendency, with tensile AE events accounting for approximately 80%; increased web-end CFST steel tube thickness may enhance confinement and help mitigate brittle tensile failure. These findings provide new insights into the multi-scale damage evolution and failure mechanisms of DSC shear walls, with implications for seismic performance evaluation and future AE-based damage-state assessment of steel-concrete composite structures.