Assessment of the consistent second-order plate theory for isotropic plates from the perspective of the three-dimensional theory of elasticity

In this paper, the consistent second-order plate theory for isotropic plates is validated against the three-dimensional elasticity theory using a well-known benchmark problem of a simply-supported rectangular plate subjected to symmetric transverse sinusoidal loading. The choice of the benchmark problem is based on the fact that it allows for an exact three-dimensional elasticity solution to be derived in closed-form. In the paper, two equivalent closed-form solutions are employed for validation purposes, one of which is specifically derived for this study. Once the equivalence of the two closed-form analytical solutions is established, they are expanded into a power-law series with respect to the non-dimensionalised plate thickness. This enables a direct term-by-term comparison with the consistent second-order plate theory solution and provides a valuable mechanism to validate the consistent plate theory in purely analytical form. The term-by term comparison reveals that the first terms of the above power-law series coincide exactly with the expressions of the consistent second-order plate theory. In addition to the analytical validation, a parametric study is carried out with a view to establish the range of applicability of the consistent second-order plate theory in terms of the thickness-to-length ratio. It is demonstrated that the consistent plate theory can predict displacements and stresses in thick plates with very high degree of accuracy, such that even for very thick plates with thickness-to-length ratio of 1/2, the deviation from the three-dimensional elasticity solution is less than 1%.