Macroapproach for Ribbed and Grid Plate Systems

Macroflexibility approach is employed to obtain generalized displacements and forces of ribbed and grid plate systems. It is based on writing the compatibility for deflection between the plate and the rib line, or at a node point between a stringer and a diaphragm and determining the interactive forces by applying the general orthogonality conditions. First-order summation equations are inverted in closed form to obtain the closed-form displacement solutions of stiffened plate system. The displacement solutions are general with respect to the loading and the boundary conditions on two opposite sides. However, stiffness and spacing of interior beams in either direction must be identical. The Macroflexibility approach can be extended for interior beams with varying properties where the final summation-integral equations need to be solved in open form. Validity of this approach is checked by numerically comparing the results against the existing technique that are exact.