University of Tehran Press Journal of Computational Applied Mechanics 2423-6713 57 2 2026 04 01 Vibration Analysis of Stiffened Composite Plates Reinforced by Nano materials: Analytical and Experimental Investigations. 257 274 105241 10.22059/jcamech.2025.408569.1746 EN Adwaa Abdulmajeed Department of Prosthetics and Orthotic Devices Engineering, Techniques College of Medical Rehabilitation and Prosthetics, Al-Furat Al-Awsat Technical University, Najaf, Iraq Emad K. Najim Ministry of Industry and Minerals, State Company for Rubber and Tires Industries, Najaf, 00964, Iraq Firas Taher Al-Maliky Fuel and Energy Techniques Engineering Department, College of Engineering, AL-Mustaqbal University, 51001, Babylon, Iraq Royal Madan Department of Mechanical Engineering, Graphic Era (Deemed to be University), Dehradun 248002, Uttarakhand, India Journal Article 2025 12 22 In this work, rectangular plate samples are designed and fabricated using four arrangements: pure epoxy with a stiffener, pure epoxy plate without a stiffener, homogeneous composite plate with 0.5% Vf and a stiffener, and homogeneous composite plate with a FGM stiffener. The mathematical model is formulated based on the first-order shear deformation theory (FSDT). The free vibration test is conducted, and the signal is analyzed to obtain the free vibration characteristics. The results show that the homogeneous composite plate with 2% Vf and FGM stiffener exhibited a significant improvement in the natural frequency. However, using a Functionally Graded Material (FGM) stiffener and increasing the nano-volume fraction increases the natural frequency. Also, the plate without any filler (pure epoxy) and without a stiffener has the lowest frequencies among the composite plates employed. The discrepancy between the analytical and experimental techniques was no more than 10%. https://jcamech.ut.ac.ir/article_105241_f558d98a97debd62ecfa1061452f8d97.pdf