Acoustic Emission During Failure of a Composite Under the von Mises Criterion with Local Structural Defects

This study investigates the effect of local structural defects on the acoustic emission (AE) response during composite failure under the von Mises criterion. A fiber bundle model (FBM) is used to simulate failure under transverse shear while varying the initiation time of fracture, which corresponds to changes in defect size or heterogeneity. The results show that increasing the failure initiation time leads to a decrease in AE signal amplitude and a simultaneous increase in its duration, reflecting a slower energy release during fracture. These relationships were confirmed experimentally on fine-grained composite specimens. The obtained findings demonstrate that amplitude–time AE parameters can serve as sensitive indicators of defectiveness and local heterogeneity in composite materials, offering potential for improved nondestructive evaluation and structural health monitoring.