scholarly journals Influence of Strain Ratio and Environment on Bending Fatigue Life and Form of Fracture Surface in TiNi Shape-Memory Alloy Wire.

2003 ◽  
Vol 69 (678) ◽  
pp. 420-426
Author(s):  
Hisaaki TOBUSHI ◽  
Kenichi NAKAGAWA ◽  
Hiroyuki IWANAGA ◽  
Masato ENDO
Keyword(s):  
Fatigue Life ◽  
Shape Memory Alloy ◽  
Fracture Surface ◽  
Shape Memory ◽  
Strain Ratio ◽  
Shape Memory Alloy Wire ◽  
Bending Fatigue ◽  
Alloy Wire

Fatigue properties of a TiNi shape-memory alloy wire subjected to bending with various strain ratios

2003 ◽  
Vol 217 (2) ◽  
pp. 93-99 ◽  
Author(s):  
Y Furuichi ◽  
H Tobushi ◽  
T Ikawa ◽  
R Matsui
Keyword(s):  
Fatigue Life ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Strain Ratio ◽  
Fatigue Properties ◽  
Test Machine ◽  
Shape Memory Alloy Wire ◽  
Alloy Wire ◽  
Rotating Bending ◽  
Alternating Bending

A fatigue-test machine for alternating bending of a wire under strain-controlled conditions was developed. Bending-fatigue tests on a TiNi shape-memory alloy wire were then performed for various strain ratios. The results obtained can be summarized as: (1) the fatigue life curves under alternating bending and pulsating bending, as expressed by the relationship between maximum strain and the number of cycles to failure, systematically follow the order of strain ratio; (2) the larger the strain ratio, the longer the fatigue life; (3) the fatigue life under rotating bending is shorter than that under alternating bending; (4) the increase in temperature during cyclic bending becomes larger in the order: rotating bending, alternating bending, pulsating bending. The fatigue life decreases in proportion to the increase in temperature; and (5) the fatigue limit of strain for alternating bending, pulsating bending and rotating bending is in the region of R-phase transformation.

scholarly journals Influence of Strain Ratio on Bending Fatigue Life and Fatigue Crack Growth in TiNi Shape-Memory Alloy Thin Wires

2006 ◽  
Vol 47 (3) ◽  
pp. 759-765 ◽  
Author(s):  
Ryosuke Matsui ◽  
Yoshiyasu Makino ◽  
Hisaaki Tobushi ◽  
Yuji Furuichi ◽  
Fusahito Yoshida
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Crack Growth ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Crack Growth ◽  
Strain Ratio ◽  
Bending Fatigue ◽  
Thin Wires

Cyclic Deformation and Fatigue of a TiNi Shape-Memory Alloy Wire Subjected to Rotating-Bending

1997 ◽  
Author(s):  
H. Tobushi ◽  
T. Hachisuka ◽  
T. Hashimoto ◽  
S. Yamada
Keyword(s):  
Fatigue Life ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Rotational Speed ◽  
Cyclic Deformation ◽  
Rhombohedral Phase ◽  
Shape Memory Alloy Wire ◽  
Alloy Wire ◽  
Deformation Properties ◽  
Rotating Bending

Abstract The cyclic deformation and fatigue of a TiNi shape-memory alloy wire was studied by carrying out rotating-bending fatigue tests at various strain amplitudes, temperatures and rotational speeds in air and in water. The results were summarized as follows: (1) for strain amplitudes in the rhombohedral-phase transformation region, the fatigue life was longer than 107 cycles and the deformation properties did not change under cyclic deformation; (2) for the strain amplitudes in the martensitic transformation region, the fatigue life was shorter than 105 cycles and the higher the temperature, the shorter was the fatigue life; (3) the rotational speed did not affect the fatigue life in water but a higher rotational speed led to a shorter fatigue life in air.

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