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R. Lackner, H.A. Mang:
"Adaptive FE Ultimate Load Analysis of Reinforced Concrete Plates and Shells";
in: "CD-ROM Proceedings of the Structural Engineers World Congress (SEWC)", Elsevier Science, Oxford, 1998, 10.

The paper contains a report on the development of an incremental error estimator for 2D elastoplasticity with special emphasis on softening in consequence of cracking of surface structures made of concrete. This estimator is the basis for adaptive ultimate load analysis of reinforced concrete plates and shells by the finite element method (FEM). The starting point for the theoretical formulation is a recovered stress distribution obtained from smoothing algorithms as proposed by [Zienkiewicz and Zhu, 1987]. It is employed for the evaluation of both the elastic and the plastic contribution to the error measure as well as for the transfer of state variables from the old to the new mesh. This transfer constitutes a part of an adaptive calculation scheme allowing continuation of the calculation at the last load level at which the error criterion has failed and, hence, the mesh was refined. For the generation of the new mesh the advancing front technique is used. The proposed error estimator, which is part of the adaptive calculation scheme, is applied to two plate problems (plane stress). Details concering the application to shell problems will be given at the Congress.

Keywords: adaptivity