Combined effect of mass and two-parameter elastic foundation on the free vibration characteristics of laminated composite plates using a FSDT- based finite element method

PurposeThe prevalence of laminated composite plates is widespread in structural design and engineering applications, including aerospace, defence and marine structures, due to their high stiffness and strength-to-weight ratios, corrosion resistance and mouldability. The dynamic analysis of laminated composite plates is crucial to ensure structural integrity. These plates often carry attached mass and rest on elastic foundations, yet limited research has explored the combined effects of attached masses and elastic foundations on the free vibration characteristic of composite plates, despite their widespread applications in the form of aircraft panels with sensors, marine vessels with mounted equipment and various spacecraft components.MethodsThis study employs a fast converging and computationally efficient 9-noded 45 degrees of freedom isoparametric finite element formulation to investigate the free vibration characteristics of laminated composite plates with mass and elastic foundations. The plate equations of motion are based on the First Order Shear Deformation Theory (FSDT), and the eigenvalues are obtained using Hamilton's principle.ResultsParametric studies are performed to analyse the effect of magnitude and distribution of mass on the free vibration characteristics of the plate resting on elastic foundations with various stiffness parameters. Various plate material and geometric properties are considered, and the nodal effect on the mass placement is investigated.ConclusionThis study shows that strategically placing the mass at a nodal point can make the mass act as a tuned mass damper to dampen specific vibration modes while keeping other vibration modes unaffected. Further, the Winkler elastic foundation significantly alters the dynamic behaviour of plates with distributed mass, whereas the Pasternak foundation alters the behaviour of plates with both concentrated and distributed mass.