Vibration of stiffened skew Mindlin plates

This paper presents a formulation for the free vibration analysis of skew Mindlin plates with intermediate parallel stiffeners attached in two directions. The Mindlin theory is used to account for the effects of transverse shear deformations and rotary inertia of the plate while the Engesser theory associated with the consideration of torsion is employed for stiffeners. Based on these two theories, the energy functionals for the plate system have been derived. To obtain the vibration frequencies, these energy functionals are minimized with the shape functions assumed in a set of two-dimensional mathematically complete polynomials. This procedure has been implemented numerically to compute the vibration solutions. Convergence studies have been performed to verify the accuracy of this method. Sets of first known results have been presented for several stiffened plate structures. © 1995 Springer-Verlag.