Torsional whole-life transformation ratchetting under pure-torsional and non-proportional multiaxial cyclic loadings of NiTi SMA at human-body temperature: Experimental observations and life-prediction model

Di Song; Guozheng Kang; Chao Yu; Qianhua Kan; Chuanzeng Zhang

doi:10.1016/j.jmbbm.2019.03.010

Torsional whole-life transformation ratchetting under pure-torsional and non-proportional multiaxial cyclic loadings of NiTi SMA at human-body temperature: Experimental observations and life-prediction model

J Mech Behav Biomed Mater. 2019 Jun:94:267-278. doi: 10.1016/j.jmbbm.2019.03.010. Epub 2019 Mar 14.

Authors

Di Song¹, Guozheng Kang², Chao Yu³, Qianhua Kan², Chuanzeng Zhang⁴

Affiliations

¹ School of Mechanical and Electrical Engineering, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731, PR China; State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, PR China.
² School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031, PR China.
³ School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031, PR China. Electronic address: chaoyu@home.swjtu.edu.cn.
⁴ Department of Civil Engineering, University of Siegen, Siegen 57068, Germany.

PMID: 30933835
DOI: 10.1016/j.jmbbm.2019.03.010

Abstract

Torsional whole-life transformation ratchetting is investigated under pure-torsional and non-proportional multiaxial loadings of NiTi SMA micro-tubes at human-body temperature (310 K), where three paths of torsional loadings and five paths of multiaxial ones are considered. It is observed that the evolution of the torsional whole-life transformation ratchetting depends strongly on the loading paths and stress levels, and the fatigue lives of pure-torsional loadings decrease faster than that of uniaxial and multiaxial ones with the increase of peak stress. Based on the experimental investigations, a life-prediction model which depends on the applied stress levels is proposed for NiTi SMA micro-tubes, where the martensite transformation and reorientation of NiTi SMAs are considered. The predicted fatigue lives under uniaxial, torsional and non-proportional multiaxial loadings are mostly located within the triple error band.

Keywords: Fatigue life-prediction model; NiTi SMAs; Non-proportional multiaxial cyclic loading; Torsional cyclic loading; Torsional transformation ratchetting.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Biomechanical Phenomena
Humans
Materials Testing*
Nickel*
Stress, Mechanical
Temperature*
Titanium*
Weight-Bearing

Substances

titanium nickelide
Nickel
Titanium