ON THE EQUATIONS OF AN 8TH-ORDER THEORY FOR NONHOMOGENEOUS TRANSVERSELY ISOTROPIC PLATES

We obtain the equations of a two-dimensional eighth-order theory for t he transverse bending of transversely isotropic plates, through use of a variational equation for displacements and transverse stresses. We show that, for sufficiently thin plates, the solution involves an equa tion of the fourth order for an interior solution contribution, and tw o equations of the second order for edge zone solution contributions. One of these accounts for transverse shear stress effects, in nearly t he same manner as this effect occurs in the sixth-order theory, and th e other accounts for transverse normal stress effects which are neglec ted in the sixth-order theory.