Prognostic Assessment of Symmetric Perpendicular Edge Cracks on the Vibration Characteristics of Orthotropic Cantilever Composite Plates

This study investigates the free vibration characteristics of orthotropic cantilever composite plate containing symmetric double edge cracks. A detailed finite element analysis (FEA) was conducted in ANSYS APDL to investigate the influence of crack length (a/W=0 0.04) and crack location (x_c/L=0-0.75) on the first six natural frequencies. The results show a consistent frequency reduction with increasing crack length and proximity to the clamped edge, while higher-order modes display greater sensitivity due to localized strain energy near the cracks. A semi-empirical relation was also developed to predict frequency degradation based on crack geometry and position, achieving excellent agreement with numerical data (R^2>0.99). The findings provide a concise framework for vibration-based damage detection and structural health monitoring (SHM) of orthotropic composite structures. Unlike previous works that primarily examined single-edge or isotropic configurations, this study uniquely quantifies the coupled influence of symmetric double-edge cracks in orthotropic cantilever plates, thereby extending the understanding of multi-crack interaction effects in composite dynamics.