Hygrothermal Loading Effects in Bending Analysis of Multi layered Composite Plates

The paper analyzes the hygrothermal loading effects in the bending of multilayered composite plates. Refined two-dimensional models are used to evaluate these effects, they are implemented in the framework of the Carrera's Unified Formulation (CUF) which also allows classical models to be obtained. Hygroscopic and thermal effects are evaluated by means of hygroscopic and thermal load applications, respectively. Such loads can be determined via a priori linear or constant moisture content and temperature profiles through the thickness of the plate, or by calculating them via the solution of the Fick moisture diffusion law and the Fourier heat conduction equation, respectively. These equations are solved in steady-state conditions and in a range of moisture content and temperature variations which requires constant material properties to be considered. Comparisons between assumed linear and calculated moisture content and temperature profiles are also made for different thickness ratios and lamination sequences. The presence of hygroscopic and thermal effects modifies the bending response in composite structures by increasing the maximum deflection and the discontinuity values of in-plane stresses at the layer interfaces.