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R. Lackner, H.A. Mang:
"Adaptive FEM for the Analysis of Concrete Structures";
in: "Proceedings of the EURO-C 1998 Conference on Computational Modelling of Concrete Structures", Balkema, Rotterdam, 1998, 897 - 919.

The paper reports on an incremental error estimator for 2D elastoplasticity including softening because of cracking of concrete. This estimator is the basis for adaptive finite element (FE) analysis. An important issue of the theoretical formulation is the recovered stress distribution. It is obtained from a discontinuous recovery method which is based on the smoothing algorithm proposed by Zienkiewicz and Zhu (1987). This recovery method is employed for the evaluation of both the elastic and the plastic contribution to the error. It is also used for the transfer of state variables from the old to the new mesh. This transfer is part of an adaptive computation scheme allowing continuation of the calculation at the last load level at which the error criterion has failed. At this load level the mesh is refined. The new mesh is generated by means of the advancing front technique. This technique has been extended to consideration of a prescribed orientation of element edges (mesh alignment) according to the principal directions of the total strains. The proposed error estimator is applied to adaptive analysis of three plate problems (plane stress).

Keywords: adaptivity