A Multifeature Acoustic Emission Approach Integrating Delamination Damage Function for Quantitative Damage Monitoring in Composite Fan Blade Tenons

ABSTRACT Acoustic emission (AE) can monitor damage in composite structures in real time, but its use in complex aerospace components remains limited by overlapping signal sources, test‐condition sensitivity, and weak coupling with mechanical response. This study develops a delamination‐oriented AE framework that combines multifeature signal processing with a delamination damage function (DDF). Short‐beam shear tests were used to build a laminate‐specific AE database. AE events were partitioned into four clusters by principal component analysis and fuzzy C‐means clustering, and the resulting peak‐frequency bands were checked by interrupted tests and ultra‐depth‐of‐field 3D optical microscopy and scanning electron microscopy (SEM). These frequency bands and cluster‐mode associations are specific to the investigated laminate and AE acquisition setup, and they require recalibration for other material systems or stacking sequences. A transient damage contribution index was then combined with mechanical energy release to construct the DDF, producing temporally localized responses to delamination‐related AE activity. The framework was evaluated in tensile tests of full‐scale composite fan blade tenons with synchronized AE and digital image correlation (DIC). Using the SBS‐derived frequency characteristics as prior information, the DDF highlighted delamination‐dominated events whose timing agreed with DIC‐observed delamination onset and progression.