An experimental study of the superelastic behavior in NiTi shape memory alloys under biaxial proportional and non-proportional cyclic loadings

Fatigue of Nitinol: The state-of-the-art and ongoing challenges

“…Similar to uniaxial loading, the hysteresis loop of both superelastic and thermally martensitic is subjected to change in the first few cycles of shear loading (Jensen, 2005;Wang et al, 2010).…”

“…The hysteresis loops for the superelastic (Wang et al, 2010) and thermally martensitic Nitinol (Jensen, 2005) under force-controlled shear deformation becomes narrower as the number of cycles increases. This indicates a reduction in the ability of the superelastic as well as thermally martensitic Nitinol in absorbing and dissipating energy under cyclic shear loading.…”

Effect of martensite reorientation and reorientation-induced plasticity on multiaxial transformation ratchetting of super-elastic NiTi shape memory alloy: New consideration in constitutive model

“…However, the experimental observations on the transformation ratchetting of super-elastic NiTi SMA under non-proportional multiaxial cyclic loading conditions are much fewer than that under the uniaxial ones, and only a few recent works (Wang et al, 2010;Saleeb et al, 2013;Song et al, 2014b) can be referred to. As discussed by Song et al (2014b), martensite reorientation plays a critical role in the non-proportional multiaxial transformation ratchetting of super-elastic NiTi SMA: firstly, martensite reorientation is one of the main inelastic deformation mechanisms occurred in the NiTi SMA under non-proportional multiaxial loading condition; secondly, reorientation-induced plasticity promotes the accumulation of peak and valley strains and then make the transformation ratchetting presented under the non-proportional multiaxial loading condition much higher than those obtained under the uniaxial one.…”

Non-proportional multiaxial whole-life transformation ratchetting and fatigue failure of super-elastic NiTi shape memory alloy micro-tubes

“…Recently, Wang et al [18] and Song et al [19] performed some multiaxial strain-controlled and stress-controlled cyclic tests with different non-proportional load paths to observe the multiaxial cyclic deformation of the NiTi SMA, respectively. A significant pathdependence of non-proportional multiaxial cyclic deformation was observed.…”