Transverse Normal Stress Effects in Multilayered Plates

An evaluation of transverse normal stress σ_zz effects in multilayered plate modeling is given in this paper. Mixed theories with continuous interlaminar transverse shear and normal stresses have been formulated on the basis of Reissner's theorem (Reissner, 1984). The case in which the number of the displacement variables preserves independence by the number of constitutive layers, N₁, has been investigated. Classical models based on standard displacement formulations have been discussed for comparison purposes. The analysis of transverse stress effects has been conducted by allowing a constant, linear, and higher-order distribution of the transverse displacement components in the plate thickness directions. Related two-dimensional models are compared for the static response of symmetrically and unsymmetrically layered, simply supported plates made of isotropic as well as orthotropic layers. The conducted numerical investigation and comparison with available results have above all led to the following conclusions. The possibility of including σ_zz makes the used mixed theories more attractive that other available modelings. σ_zz plays a fundamental role in thick laminate plates analysis. Such a role increases in transversely anisotropic multilayered plate analysis. With an increase of the plate thickness, a very accurate description of σ_zz requires modelings whose number of independent variables depends on N₁.