Microplasticity and energy dissipation in very high cycle fatigue

Créé le : 07/02/2013

Véronique Favier, Ngoc Lam Phung, Nicolas Ranc, Thierry Bretheau, Jacques Groslafaige, Gérard Roger, Wilfrid Seiler, Fédéric Valès, Danièle Wagner, Chong Wang, Claude Bathias, Julie Cédelle, Isabelle Ranc, André Chrysochoos, Antoine Blanche, Bertrand Wattrisse, Gérard Camp, Alain Clary, Yves El Kaim, François Jourdan, Fabienne Grégori, Brigitte Bacroix, André Galtier, Guillaume Thoquenne, Haël Mughrabi - 01/11/2011 - RC Fatigue Design…
This paper presents the ongoing DISFAT project, financially supported by the French National Agency ANR and its white program. It aims at a deeper understanding of mechanisms leading to crack initiation in metals and alloys in Very High Cycle Fatigue (VHCF). In contrast to conventional fatigue tests, detecting irreversible microstructural changes using cyclic stress-strain curves analysis is no more possible, at lultrasonic frequencies, at least with conventional measurement systems, since the macroscopic behavior is quasi-elastic. To cope with this problem, we propose to use the energy signature of the deformation mechanisms. The main challenge of this project results from the fact that the energy and mechanical manifestations as well as the microstructural “evidences” of the mechanisms of interest involve very low signals. In this paper, we explain our strategy and present some results on fcc and bcc single-phase polycrystals.
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André Galtier
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