Four-variable refined plate theory for forced-vibration analysis of sigmoid functionally graded plates on elastic foundation

摘要: Abstract A refined higher-order shear deformation theory is developed for the analysis of free and forced vibration sigmoid functionally graded materials (S-FGM) plates. The theory, proposed in this paper, considers parabolic distribution transverse stress, satisfies condition that requires stress to be zero on upper lower surfaces plate, without correction factor. Unlike conventional even though it uses only four unknown variables, shares strong similarities with classical plate (CPT) many aspects such as boundary conditions, equation motion, stress-resultant expressions. material properties are assumed vary according two power law distributions volume fractions constituents. equations motion derived from Hamilton׳s principle. solutions a simply supported derived, comparative carried out by comparing results obtained first-order another, theory. provide accurate relevant free-vibration problems Functionally Graded Materials (FGM) Analytical forced-vibration presented so reveal effects index, length, aspect ratio, loading time interval, elastic medium parameters side-to-thickness ratio dynamic response.