The dynamic behavior of composite structures is crucial for aerospace and automotive applications where weight reduction and vibration control are essential. This study investigates the free vibration characteristics of orthotropic composite plates reinforced with aluminum oxide (Al₂O₃) particles. Limited research exists on the combined effect of Al₂O₃ reinforcement percentages and fiber orientation on the dynamic properties of composite plates. The study aims to analyze the influence of varying Al₂O₃ content (2%, 5%, and 8% by weight) on the natural frequencies of glass fiber-reinforced PMMA composite plates with different stacking sequences. The study employs Classical Laminate Theory (CLT) with Rayleigh-Ritz method for analytical modeling, assuming thin plate theory (Kirchhoff), neglecting shear deformation, and considering simply supported boundary conditions. Finite Element Method (FEM) using ANSYS Workbench with SHELL181 elements validates the analytical results. Experimental verification uses impact hammer testing with accelerometer measurements. The 8% Al₂O₃ reinforcement showed optimal mechanical properties with the highest natural frequency (104.51 Hz) achieved by (90°, 30°, 45°, 30°, 90°) stacking sequence. Analytical-numerical correlation showed excellent agreement with discrepancies below 3% for most modes, while experimental validation confirmed model accuracy with errors ranging from 0.03% to 3.69%.
