Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5015173 | International Journal of Fatigue | 2017 | 29 Pages |
Abstract
Multiaxial whole-life transformation ratchetting and fatigue failure of superelastic NiTi SMA micro-tubes are observed in the non-proportionally multiaxial stress-controlled cyclic tests at the human-body temperature (310Â K) under five different multiaxial loading paths. The effects of the axial peak stress and stress amplitude on the transformation ratchetting and fatigue life are addressed. It is found that the super-elastic NiTi SMA micro-tubes sustain more significant path-dependent fatigue failure in the multiaxial cyclic tests with lower axial peak stress and stress amplitude, while the fatigue lives of the NiTi micro-tubes under different loading paths are gradually converged with the increasing axial peak stress and stress amplitude. Based on the experimental findings, a fatigue failure model is proposed to predict the multiaxial fatigue life of the super-elastic NiTi SMA micro-tubes by considering the initial/saturated dissipation energy and the non-proportionality of the loading paths. It is shown that the predicted multiaxial fatigue lives agree with the experimental ones fairly well.
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Authors
Di Song, Guozheng Kang, Qianhua Kan, Chao Yu, Chuanzeng Zhang,