A NOVEL METHOD OF GENERATING EXACT STIFFNESS MATRICES FOR AXISYMMETRICAL THIN-PLATE AND SHELL ELEMENTS WITH SPECIAL REFERENCE TO AN ANNULARPLATE ELEMENT

The generation of a stiffness matrix for each different element of a g iven body or structure is a key step in any finite element procedure. Accurate evaluation of an elemental stiffness matrix is obviously nece ssary for solution accuracy. Usually, however, approximate methods bas ed upon the concept of shape functions are used to derive an elemental stiffness matrix [k]. Since such elemental stiffness matrices are onl y approximate, solution accuracy becomes somewhat uncertain. Fine mesh es are often used to obtain acceptable solution accuracy. With the mes h becoming finer, however, the total number of degrees of freedom and unknown variables becomes large. Computational time increases. Interna l stress calculations with the help of approximate displacement fields are also not very accurate. The present work concerns the generation of exact stiffness matrices for axisymmetric plate and shell elements for use in a finite element package. The proposed method obviates the need for fine meshes, reduces computational time and ensures greater s olution accuracy.