Skip to Main content Skip to Navigation
Theses

Fatigue polycyclique des structures métalliques : durée de vie sous chargements variables.

Abstract : The purpose of this work is to present a reliable model for the assessment of the lifetime at crack nucleation of metallic structures, working in finite life regime of high-cycle fatigue and subjected to variable amplitude multiaxial loadings. This deterministic model is characterized by its possible use in the industry which demands certain requirements : predictive model on structures without counting of cycles, model of simple use (not too many parameters to be identified, not too many fatigue data to be used and less expensive calculation) and applicable on a broad variety of metallic materials for any type of repeated blocks of variable amplitude multiaxial loading. After a bibliographical analysis of the criteria suggested in this field, none of them is used in design offices, and does not fulfill completely the industrial requirements. The model is based on a mesoscopic approach. Two features characterise it : (i) the choice of the accumulated plastic meso-strain per stabilized cycle "pc s as relevant parameter in fatigue design with the use of a hydrostatic stress dependent elastoplastic model to evaluate it, (ii) the assessment of the lifetime at crack nucleation by the definition of a damage factor depending on the accumulated plastic meso-strain per stabilized cycle "pc s and some material and loading parameters. The model has six parameters identified with one SN curve and two fatigue limits. The validation of the model is ensured via fatigue tests (from the literature) under constant and variable amplitude multiaxial loadings, carried out on five materials. Good correlations with the experimental fatigue lives were obtained. Finally, the model is used to determine the lifetime of a vehicle suspension spring working in finite life regime.
Complete list of metadatas

https://pastel.archives-ouvertes.fr/pastel-00002116
Contributor : Ecole Polytechnique <>
Submitted on : Thursday, July 29, 2010 - 10:15:51 AM
Last modification on : Thursday, September 24, 2020 - 4:00:22 PM
Long-term archiving on: : Thursday, November 4, 2010 - 9:43:01 AM

Identifiers

  • HAL Id : pastel-00002116, version 1

Citation

Mohamad Jabbado. Fatigue polycyclique des structures métalliques : durée de vie sous chargements variables.. Mécanique des matériaux [physics.class-ph]. Ecole Polytechnique X, 2006. Français. ⟨pastel-00002116⟩

Share

Metrics

Record views

1882

Files downloads

12605