Influence of Nanoparticle Reinforcement on the Dynamic Characteristics of Fiber Metal Laminate Composite Beams

This study examines the vibration behavior of fiber-metal laminate (FML) composite cantilever beams reinforced with multi-walled carbon nanotube (MWCNT) nanoparticles, employing both experimental and numerical approaches. Vibration analysis of FML beams is essential to ensure structural stability, fatigue resistance, and reliability in critical applications such as aircraft fuselage panels, ship hulls, and other lightweight load-bearing components. Experimental analyses were performed using a Fast Fourier Transform (FFT) analyzer, while numerical simulations were conducted in ANSYS under cantilevered boundary conditions. The natural frequencies and vibration responses of 2/1 FML composite beam configurations were evaluated to determine the influence of varying MWCNT content (3–5% by weight). The results reveal that an increase in nanoparticle concentration leads to higher bending natural frequencies and lower vibration amplitude ratios. Among the tested specimens, the 5% MWCNT-reinforced FML beam demonstrated superior dynamic stability compared to the 3% and 4% specimens, whereas the 3% MWCNT composites exhibited a more pronounced damping effect. Theoretical and numerical predictions of vibration amplitude ratios and natural frequencies showed strong agreement with experimental results. Furthermore, it was observed that increasing the beam length reduced the natural frequencies of the composite beams. Overall, the study confirms that MWCNT reinforcement significantly enhances the dynamic performance of FML composites within the investigated range. These results offer valuable insights for structural health monitoring and integrity assessment of advanced laminated composites. Future research should explore MWCNT concentrations beyond 5%, as agglomeration effects may influence the observed frequency trends. It is also found that the vibration amplitude gradually decreases from the free end to the fixed end of the composite FML cantilever beam when the beam vibrates at the first bending natural frequency.