Large deflection elastic-plastic analysis of cylindrical shells using the finite strip method

A transversely-curved finite strip formulation for the static analysis of circular cylindrical shells is presented. The finite strip analysis is carried out by using one or two analytical modes in the longitudinal direction to determine the response of cylindrical shells subjected to uniform loads. Both linear and quadratic variation of membrane displacements in the curved direction are investigated and it is found that the quadratic variation is far superior. The effect of large deformations is incorporated in the present analysis by including the first order non-linearities in the strain-displacement relations. The material behavior is assumed to be isotropic elastic-plastic. The plasticity portion uses the von-Mises yield criteria, and the associated flow rule. For the examples considered, a bi-linear stress-strain relation is assumed. Numerical integration of the virtual work equations is carried out using Gaussian Quadrature. The number of integration points in a given direction is determined by observing the individual terms in the integration or by past experience. The resulting set of non-linear equations is solved iteratively by employing the Newton-Raphson scheme. Numerical investigations of the method are carried out by modelling cylindrical shells subjected to self-weight or pressure load. These investigations compare the results for laterally loaded cylindrical shells with simply supported or clamped boundaries with analytical and numerical results. The results show that employing one bending mode and one or two membrane modes is sufficient to yield engineering accuracy for design purposes.Applied Science, Faculty ofCivil Engineering, Department ofGraduat