In this paper, a hygrothermomechanical behaviour of simply supported, composite layered rectangular plates is presented. The analysis is based on use of the Finite Element (FE) method and the full third-order displacement theory. Numerical examples are presented for symmetrically in-axis (0° /90° /90° /0°) and off-axis ( 45° / - 45° / -45° / 45°) layered rectangular plates. | Vietnam Journal of Mechanics, NCST of Vietnam Vol. 24, 2002, No 3 (142 - 150) HYGROTHERMO-MECHANICAL BEHAVIOUR OF LAYERED COMPOSITE PLATES TRAN !CH THINH Hanoi University of Technology ABSTRACT. In this paper, a hygrothermomechanical behaviour of simply supported, composite layered rectangular plates is presented. The analysis is based on use of the Finite Element (FE) method and the full third-order displacement theory. Numerical examples are presented for symmetrically in-axis (0° /90° /90° /0°) and off-axis ( 45° / - 45° / -45° / 45°) layered rectangular plates. 1. Introduction Many composite material plates not only involve anisotropy, multilayered considerations and transverse shear deformation, but also have hygrothermal effects; which can be very important. Thus, for the final design of these structures, transverse shear deformation and hygrothermal effects must be included. Relatively few studies have been done regarding hygrothermal effects in thin and thick composite plates [1] , [2] , [3] . If transverse shear deformation effects are important, and if there is a hygrothermal environment present, t hen obtaining a solution through solving the partial differential equations with the attendant nonhomogeneous boundary conditions is a major challenge. Even if the solution is obtained it requires a major effort. Therefore, Finite Element Method is more convenient for use in design and analysis of composite plate structures. 2. Laminate deformation and hygrothermal stress The present analysis is based upon a displacement field in which the displacement components u, v, w are all of third-order in the thickness coordinate z [5], [6]: (u, v, w) = (u 0, v0, w 0) + z ('l/Jx , 'l/Jy, 'l/Jz) +z 2 (~x, ~Y' ~z) + z 3(x , y , z)· () where superscript "O" denotes mid-plane displacements. The strain components are related to the mid-plane displacements of the laminated plate as: + z(Kx , Ky, Kz) + z 2(Xx, Xy, Xz) + z 3(7]x , 7]y , 'r/z). () 2 3 (riz,
