Hygrothermal effects on the structural behaviour of thick composite laminates using higher-order theory

Here, static and dynamic characteristics of thick composite laminates exposed to hygrothermal environment are studied using a realistic higher-order theory developed recently. The formulation accounts for the nonlinear variation of the in-plane and transverse displacements through the thickness, and abrupt discontinuity in slope of the in-plane displacements at any interface. The analysis is carried out employing a C0 QUAD-8 isoparametric higher-order finite element. It is shown that the shear deformation theory without accounting for the thickness-stretching effect and slope discontinuity in the in-plane displacements may not be adequate for the analysis of fairly thick composite laminates exposed to hygrothermal loading. The significance of retaining various higher-order terms in the present model, in evaluating the deflection, buckling and natural frequency for composite laminates at different moisture concentration and temperature, is brought out through parametric study.