A dynamic model for thick elastic plates

In this paper the general equations of motion for thick elastic plates with arbitrary shape are derived by using a variational principle. In addition to the influences of the bending, the transverse shear deformation and the rotatory inertia, the proposed theory also contains the effects of the tran sverse normal stress and the membrane forces. The equations presented in th is paper can be reduced to those deduced by E. Reissner and R. D. Mindlin. Some numerical results are compared with those obtained from the Reissner-M indlin plate theory and the classical plate theory. It is found that for th ick plates there exists a dense region of frequencies and the position of f requencies is shifted, so that the influence of the transverse normal stres s must be considered. (C) 1999 Academic Press.