Optimisation structurale vis-à-vis de la fatigue des structures en alliages à mémoire de forme.

Abstract : This thesis presents a comprehensive and effi cient structural optimization approach for shape memory alloys (SMAs) with respect to fatigue. The approach consists of three steps: First, the development of a suitable constitutive model capable of predicting, with good accuracy, the stabilized thermomechanical stress state of a SMA structure subjected to multiaxial nonproportional cyclic loading. The dependence of the saturated residual strain on temperature and loading rate is discussed. In order to overcome numerical convergence problems in situations where the phase transformation process presents little or no positivehardening, the large time increment method (LATIN) is utilized in combination with the ZM (Zaki-Moumni) model to simulate SMA structures instead of conventional incremental methods. Second, a shakedown-based fatigue criterion analogous to the Dang Van model for elastoplastic metals is derived for SMAs to predict whether a SMA structure subjected to high-cycle loading would undergo fatigue. The proposed criterion computes a fatigue factor at each material point, indicating its degree of safeness with respect to high-cycle fatigue. Third, a structural optimization approach, which can be used to improve the fatigue lifetime estimated using the proposed fatigue criterion is presented. The prospects of this work include the validation of the optimization approach with experimental data.
Complete list of metadatas

https://pastel.archives-ouvertes.fr/tel-01617547
Contributor : Abes Star <>
Submitted on : Monday, October 16, 2017 - 4:49:18 PM
Last modification on : Wednesday, July 3, 2019 - 10:48:04 AM

File

65147_GU_2017_archivage.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01617547, version 1

Citation

Xiaojun Gu. Optimisation structurale vis-à-vis de la fatigue des structures en alliages à mémoire de forme.. Mechanics of materials [physics.class-ph]. Université Paris-Saclay, 2017. English. ⟨NNT : 2017SACLY012⟩. ⟨tel-01617547⟩

Share

Metrics

Record views

264

Files downloads

196