Publication :


Stratégie de calcul robuste et adaptative pour la simulation de l'endommagement et de la rupture des structures composites stratifiées

Authors: B. Douchin
Year: janvier 2000
Thèse de doctorat de Ecole Normale Supérieure de Cachan
ISBN : 2-11-091936-1

Abstract :
The thesis relates to the prediction of the intensities of the damage mechanisms which develop within the laminated composite structures. The modeling of such mechanisms is based on an approach called "mesomodeling" initially developed at the L.M.T.-Cachan fifteen years ago and constantly improved since then. Further enhancements may still be achieved at the simulation level considering the standard incremental methods are not convenient when applied to phenomena combining many difficulties (brutal localization, damage...). The thesis presents a robust resolution method driven by cost efficiency and calculation control ability. The new strategy of resolution is based on the not incremental LATIN method introduced by Ladevèze in 1985. This approach -already validated on many other cases- proved its interest for the processing of high magnitude problems. In order to check its adequacy, the extension of this method to softening materials was carried out through the implementation under Matlab of a prototype software dedicated to the resolution of unidimensional (visco)plastic with softening problems able to describe with robustness the complete ruin by damage of the material. In addition, an error estimator was defined so as to validate previously performed calculations. This estimator -based on the concept of constitutive relation error- extends the concept of dissipation error to the behaviors with softening. When this behavior is expressed in a standard form, two contributions to the error are built, one on the state laws and the other on the evolution laws. These structures use the properties of the Legendre-Fenchel transform, starting from the convex potentials governing the constitutive relations. This error estimator is used as termination criterion of the LATIN iterative algorithm, and furthermore allows the adaptation of the discretisation parameters through a fine control of calculation while achieving a reduction of the calculation cost.

Bibtex citation :
Author={Douchin, B.},
Title={Strat\'egie de calcul robuste et adaptative pour la simulation de l'endommagement et de la rupture des structures composites stratifi\'ees},
School={Ecole Normale Supérieure de Cachan},

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