Skip to Main content Skip to Navigation
Theses

Lois d'endommagement incrémentales isotrope/anisotropes pour applications thermomécaniques complexes

Abstract : Incremental damage laws présent many advantages in ternis of thermomechanical modeling. They enable to be freed fror the cycle concept in fatigue and are very convenient for complex, anisothermal loadings. Différent extensions to anisotropy of Lemaitre's isotropic damage model are proposed, identified on the cobalt based superalloy Haynesl88 uses for the manufacturing of turbomachines combustion chambers. The aim is the détermination of crack initiation condition at the combustion chamber scale for ils design, with the Finite Element method. The damage model is adapted to high températures, through a coupling between viscoplasticity and damage within the thermodynamic frameworks. The stored energy damage threshold and the extension to unilatéral conditions of micro defects closure effect are presented. Various numerical résolution schemes are proposed, in the case of coupled computations, or in the case of post processing, from 3D visco plastic computations without damage. Anisothermal applications are simulated, approaching the real requests: random loading, creep under variable température, biaxial loadings, non proportional loading. The contributions of damage anisotropy and unilatéral conditions of micro defects closure effect are pointed out. Last, the robustness of the model is tested on an original structural thermal fatigue test, where a multiperforate specimen is subrnitted to a complex thermal loading, reproducing the work conditions of a combustion chamber. The good corrélation between numerical simulation and expérimental results in ternis of behaviour and lifetime allows for the validation of the lifetime prédiction method, for its industrialization.
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-00341830
Contributor : Ens Cachan Bibliothèque <>
Submitted on : Wednesday, November 26, 2008 - 10:35:04 AM
Last modification on : Thursday, December 10, 2020 - 12:32:47 PM
Long-term archiving on: : Monday, June 7, 2010 - 8:27:31 PM

Identifiers

  • HAL Id : tel-00341830, version 1

Citation

Stéphane Otin. Lois d'endommagement incrémentales isotrope/anisotropes pour applications thermomécaniques complexes. Mécanique [physics.med-ph]. École normale supérieure de Cachan - ENS Cachan, 2007. Français. ⟨tel-00341830⟩

Share

Metrics

Record views

481

Files downloads

4816