Geometrically nonlinear analysis of plates and shells

This thesis deals with the geometrically nonlinear analysis of prismatic plates and shells using the finite strip method. The analysis is based on the use of Mindlin plate theory and therefore includes the effects of transverse shear deformation. The nonlinearity is introduced via the strain-displacement equations and correspondingly the analysis pertains to problems involving moderate displacements but small rotations. The principle of minimum potential energy is used in the development of the element and the complete structure stiffness equations and latter equations are solved using Newton-Raphson method. The postbuckling performance of optimized panels with sub-stiffening is investigated. The panels have been optimized for minimum weight or maximum performance. The linear elastic eigenvalue finite strip code which has a built-in optimizer provided a practical way of doing so, at least for the initial (skin) buckling. Optimization is also used to obtain insight into the importance of different design variables, and derive a method for sizing. Linear finite strip analysis allowed the optimization of one of the sub-stiffened panels, revealing a potential for further improvement of the initial buckling load.