EFFECTS OF TORSIONAL AND BENDING RESTRAINTS OF INTERMEDIATE STIFFENERS ON THE FREE-VIBRATION OF RECTANGULAR-PLATES

An investigation of the free vibrations of isotropic rectangular plates with stiffeners, based on the Rayleigh-Ritz method, is presented. The effects of torsional restraint, in addition to the bending restraint of the stiffeners, are included in the present formulation. The kinetic energy contributions of the bending and torsional deformations of the stiffeners are also included. It is assumed that the stiffeners and the plate are in contact at all times. The assumed shape functions used in the formulation are the characteristic beam functions. The effects of the location and orientation of the stiffener and its relative stiffness to the plate, under natural frequencies and modes, are examined.