Search results

A non‐linear shallow thin shell element is described. The element is a curved quadrilateral one with corner nodes only. At each node, six degrees of freedom (i.e. three translations and three rotations) make the element easy to connect to space beams, stiffeners or intersecting shells. The curvature is dealt with by Marguerre's theory. Membrane bending coupling is present at the element level and improves the element behaviour, especially in non‐linear analysis. The element converges to the deep shell solution. The sixth degree of freedom is a true one, which can be assimilated to the in‐plane rotation. The present paper describes how overstiffness due to membrane locking on the one hand and to the sixth degree of freedom on the other hand can be corrected without making use of numerical adjusted factors. The behaviour of this new element is analysed in linear and non‐linear static and dynamic tests.

An implicit integration algorithm for elastoplastic constitutive equations in plane stress analysis is presented. The error associated with this algorithm is of the same order as the one reached in three‐dimensional analysis with the radial return algorithm. No subincrementation is needed. Moreover, the exact elastoplastic stress—strain matrix related to this algorithm is derived.