Transient hygrothermoelastic analysis of layered plates with one-dimensional temperature and moisture variations through the thickness

Transient heat and moisture diffusion and the resulting hygrothermal stress field are analysed in a layered plate subjected to hygrothermal loadings at the external surfaces. The one-dimensional transient diffusion is formulated as a one-way coupled problem wherein moisture-induced effects on heat diffusion are neglected, but the exact continuity in moisture flux at layer interfaces holds unlike existing analytical studies. An analytical solution to the diffusion problem is obtained by extending a previously derived solution for double-layered plates. Hygrothermal stresses are evaluated by superposition of stresses due to the applied temperature and moisture fields. First, numerical calculations are performed for a double-layered plate to investigate the influence of moisture-flux continuity at the layer interface on hygrothermal stress distribution. Second, the obtained solutions are applied to the hygrothermoelastic problem of a functionally graded material-like (FGM-like) non-homogeneous plate whose physical properties vary along the thickness direction. Numerical results show that the use of inappropriately simplified continuity conditions for moisture flux may cause a significant error in evaluating the transient hygrothermal stresses in a layered body. Moreover, it is demonstrated that a gradual change in the material composition of FGM-like non-homogeneous plates induces considerable hygrothermal stress relaxation.