Experimental characterization of NiTi SMAs thermomechanical behaviour using temperature and strain full-field measurements

Pauline Schlosser (1) , Denis Favier (2) , Hervé Louche (1) , Laurent Orgéas (2)

1 SYMME - Laboratoire SYstèmes et Matériaux pour la MEcatronique
2 3SR - Laboratoire sols, solides, structures - risques [Grenoble]

The tension behaviour of initially austenitic NiTi thin wall tubes was investigated using measurements of temperature and strain fields simultaneously. The first specimen was totally superelastic but the unloading was performed before the end of the loading stress plateau. The second specimen loading was performed beyond the stress plateau to allow analyzing the unloading, but was not superelastic and at a faster strain rate. Both tests show homogeneous behaviour at the beginning of the loading. Strong localisations, taking the shape of helical bands, are observed during the loading and unloading stress plateaus. To obtain quantitative energy information, allowing a better recognition of the deformation mechanisms, an estimation of the local heat sources based on image processing of the temperature fields is presented. Two methods of heat sources estimation allowing analysis of deformation mechanisms are proposed in the present paper: first during the homogeneous, then during localized stages.

Mots clés: NiTi; shape memory alloy; superelasticity; localisation; strain and temperature full field measurement; heat sources estimation

Domaines: Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]

Pauline Schlosser, Denis Favier, Hervé Louche, Laurent Orgéas. Experimental characterization of NiTi SMAs thermomechanical behaviour using temperature and strain full-field measurements. Advances in Science and Technology, 2008, 59, pp.140-149. ⟨10.4028/3-908158-16-8.140⟩. ⟨hal-00336736⟩