A modified energy-based approach for fatigue life prediction of superelastic NiTi in presence of tensile mean strain and stress
A modified energy-based approach for fatigue life prediction of superelastic NiTi in presence of tensile mean strain and stress
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DOI：
10.1016/j.ijmecsci.2016.08.012
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发表时间：
2016-10
影响因子：
7.3
通讯作者：
M. Mahtabi;N. Shamsaei
中科院分区：
文献类型：
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作者：
M. Mahtabi;N. Shamsaei
对超弹性镍钛合金的疲劳行为进行了实验研究，提出了一种基于能量的疲劳模型，该模型考虑了拉伸平均应变和应力对疲劳抗力的影响。在不同应变幅下对具有均匀量规截面的圆柱形疲劳试样进行了几次零和非零平均应变试验。实验结果表明，拉伸平均应力对超弹性NiTi合金的疲劳寿命有显著的不利影响。在应力平台上，平均应变的变化不会显著影响应力值，观察到疲劳寿命相似。提出了一种修正的基于能量的模型，以考虑平均应力和应变对超弹性NiTi疲劳行为的影响。在本研究中研究的所有模型中，提出的能量方法能够更好地将具有和不具有平均应变/应力的疲劳数据关联起来。
Fatigue behavior of superelastic NiTi (i.e. Nitinol) is experimentally investigated and an energy-based fatigue model is proposed to account for the effects of tensile mean strain and stress on fatigue resistance. Several zero and nonzero mean strain tests at various strain amplitudes were conducted on cylindrical fatigue specimens with uniform gage sections. Experimental results revealed significant detrimental effects of the tensile mean stress on the fatigue life of the superelastic NiTi. On the stress plateau, where a change in the mean strain did not significantly influence the stress value, fatigue lives were observed to be similar. A modified energy-based model is proposed to account for the effects of mean stress and strain on the fatigue behavior of superelastic NiTi. Among all the models investigated in this study, the proposed energy approach was able to better correlate the fatigue data with and without mean strains/stresses.