Details

Autor(en) / Beteiligte

• Song, Di
• Kang, Guozheng
• Kan, Qianhua
• Yu, Chao
• Zhang, Chuanzeng

Titel

Non-proportional multiaxial transformation ratchetting of super-elastic NiTi shape memory alloy: Experimental observations

Ist Teil von

• Mechanics of materials, 2014-03, Vol.70, p.94-105

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2014

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •Multiaxial transformation ratchetting of NiTi shape memory alloy is observed.•Multiaxial stress state promotes the transformation ratchetting.•Multiaxial transformation ratchetting depends remarkably on the loading path.•Axial mean stress influences the multiaxial transformation ratchetting greatly.•Dissipation energy decreases progressively with the number of cycles. Experimental observations are reported for the non-proportional multiaxial transformation ratchetting of super-elastic NiTi shape memory alloy performed under the stress-controlled cyclic tension–torsion loading conditions and at room temperature. The effect of axial mean stress on the evolutions of transformation ratchetting strain and dissipation energy per cycle during the cyclic tests is discussed firstly; and then the dependence of multiaxial transformation ratchetting on the different non-proportionally loading paths (e.g., linear, square, hourglass-typed, butterfly-typed, rhombic and octagonal paths) is investigated. The results show that the multiaxial transformation ratchetting occurs mainly in the axial direction because only the non-zero axial mean stress is used and the mean shear stress is set to be zero in the all prescribed multiaxial loading paths; and the axial peak and valley strains increase with the increasing axial mean stress and also depend significantly on the shapes of loading paths. Comparison with the corresponding uniaxial ones illustrates that the multiaxial stress states are more helpful to promote the development of transformation ratchetting, especially for the non-proportional ones.