A differential quadrature analysis of vibration for rectangular stiffened plates

Structures consisting of thin plates stiffened by a system of ribs or diaph ragms form a class of structural elements of practical importance in variou s engineering applications. A differential quadrature analysis of free vibr ation of plates with eccentric stiffeners is presented. The plate and the s tiffeners are treated separately. Simultaneous governing differential equat ions are derived from the plate dynamic equilibrium, the stiffener dynamic equilibrium, and equilibrium and compatibility conditions along the interfa ce of a plate segment and a stiffener. The plate and the stiffeners have di splacements in three dimensions. Shear forces and in-plane forces in the pl ate are considered to satisfy the compatibility at the interface of a plate segment and a stiffener. Meanwhile, in-plane inertia effects in the plate and in the stiffener are ignored. The application of the differential quadr ature method is demonstrated by three examples: a simply supported plate wi th central eccentric stiffener, a clamped square plate with central eccentr ic stiffener., and a double-ribbed plate with all edges clamped. The natura l frequencies are compared with the experimental results. and with the resu lts obtained by finite element analysis. Very good agreement was found. (C) 2001 Academic Press.