Buckling and postbuckling analysis using an assumed strain eleemtn with six dof per node

摘要

A finite element model with six degrees of freedom per node is extended to buckling and postbuckling analysis of geometrically nonlinear shell structures. The present model does not require rotational angles for description of the kinematics of deformation. The finite element model is constructed using an assumed strain formulation in which a set of assumed strain formulation in which a set of assumed strains is selectively chosen to prevent locking while maintaining kinematic stability. the assumed strain field is derived based on the nonlinear straindisplacement relations. The numerical results show the advantages of the present formulation over the conventional degenerated shell elements for pre-and postbuckling analysis. Introduction of this new kinematics of deformaiton provides a means to pinpoint a bufurcation point as well as to allow large load increments in both pre- and postbuckling ranges.