Geometrical Non-Linearity in Collapse Analysis of Thick Shells, with Application to Tubular Steel Joints

摘要

Geometrical nonlinearity is important, not only in problems involving elastic instability of thin structures, but also where they influence collapse in the material nonlinear range involving thicker members. Using a continuum approach, this paper presents the basic principles of the general finite element formulation for thick shells that have been incorporated in an existing general purpose computer program suite DIANA with a very modular architecture. The common assumptions of classical plate or shell theories have not been applied. Material nonlinearity has only been mentioned briefly, where it involves plasticity in structural steel. A comparison with the collapse analysis of a steel shell using conventional classical plate/shell theory is presented to illustrate variations that are ignored in classical theory. Experimental results on the collapse behavior of a tubular steel T-joint are briefly compared with a numerical simulation, where the theoretical effects of geometric or material nonlinearity alone are also presented.