Effect of core material on random vibration behaviour of foam-based laminated sandwich panels using a modified layerwise theory

Abstract This study investigates the vibration response of foam-based laminated sandwich panels (FLSP) under random loading. A modified layerwise displacement theory is employed to account for the varying material properties of the layers throughout the thickness. The dynamic behavior of the FLSP is analyzed using random input excitation, focusing on the impact of different foam materials on the random vibration characteristics. Additionally, the effects of the thickness of both composite and foam sections are examined. Key random parameters, including mean, standard deviation, variance, and autocorrelation, are determined for various core materials. A proof-of-concept experimental setup was developed to validate the proposed modified layerwise theory, demonstrating its effectiveness in random vibration analysis of FLSPs. The results indicate that as the softness of the core material increases, the natural frequency of the FLSP decreases. Conversely, higher core stiffness correlates with increased response parameters in random vibration, including mean value, standard deviation, and variance. Furthermore, FLSPs with stiffer core materials exhibit a higher signal correlation compared to those with softer cores.