Dynamic Stiffness Modeling of Composite Plate and Shell Assemblies

Abstract : This grant sought to develop the dynamic stiffness method for composite shell assemblies. In the first part an exact dynamic stiffness element based on higher order shear deformation theory and extensive use of symbolic algebra is developed for the first time to carry out buckling analysis of composite plate assemblies. The principle of minimum potential energy is applied to derive the governing differential equations and natural boundary conditions. The effects of significant parameters such as thickness-to-length ratio, orthotropy ratio, number of layers, lay-up and stacking sequence and boundary conditions on the critical buckling loads and mode shapes are investigated. In the second part of the grant an exact free vibration analysis of laminated composite doubly-curved shallow shells was carried out by combining the dynamic stiffness method (DSM) and a higher order shear deformation theory (HSDT) for the first time. The Wittrick-Williams algorithm is used as a solution technique to compute the eigenvalues of the overall DS matrix.