Creep-Fatigue Life Evaluation for Sn-3.5Ag Solder

2005 ◽  
Vol 128 (2) ◽  
pp. 142-150 ◽  
Author(s):  
Mineo Nozaki ◽  
Masao Sakane ◽  
Yutaka Tsukada ◽  
Hideo Nishimura
Keyword(s):  
Fatigue Life ◽  
Strain Range ◽  
Grain Boundary Sliding ◽  
Strain Waves ◽  
Life Evaluation ◽  
Creep Fatigue ◽  
Fatigue Life Evaluation ◽  
Boundary Sliding ◽  
Small Scatter ◽  
Damage Rule

This paper studies the creep-fatigue life evaluation of Sn-3.5Ag solder under push-pull loading using fast-fast, fast-slow, slow-fast, slow-slow, and strain-hold strain waves. Extensive creep-fatigue data were generated using these strain waves and the applicability of four conventional creep-fatigue damage rules, the linear damage rule, the frequency modified fatigue life, the ductility exhaustion model, and the strain range partitioning method, was examined. No conventional damage rules evaluated creep-fatigue lives accurately. Only the grain boundary sliding model, developed recently for solders, predicted creep-fatigue lives with a small scatter.

A Strain Rate Ratio Approach for Assessing Creep-Fatigue Life of 63Sn-37Pb Solder Under Shear Loading

2004 ◽  
Vol 127 (4) ◽  
pp. 407-414 ◽  
Author(s):  
Yutaka Tsukada ◽  
Hideo Nishimura ◽  
Hiroki Yamamoto ◽  
Masao Sakane
Keyword(s):  
Fatigue Life ◽  
Strain Rate ◽  
Rate Ratio ◽  
Life Prediction ◽  
Strain Range ◽  
Shear Loading ◽  
Strain Waves ◽  
Creep Fatigue ◽  
Ratio Approach ◽  
Damage Rule

This paper studies creep-fatigue life prediction under shear loading by making extensive torsion creep-fatigue experiments using four kinds of strain waves. The linear damage rule, strain range partitioning method, frequency modified fatigue life, and ductility exhaustion model were applied to the experimental data, but no methods accurately predicted the creep-fatigue life. A new method based on the strain rate ratio, which predicted the creep-fatigue life within a factor of 4 scatter band, was developed.

Fatigue and Creep-Fatigue Life Evaluation of U-Shaped Bellows

1992 ◽  
Vol 114 (3) ◽  
pp. 280-291 ◽  
Author(s):  
K. Tsukimori ◽  
T. Yamashita ◽  
M. Kikuchi ◽  
K. Iwata ◽  
A. Imazu
Keyword(s):  
Fatigue Life ◽  
Evaluation Method ◽  
Strain Range ◽  
Creep Damage ◽  
Fatigue Tests ◽  
Reliable Operation ◽  
Life Evaluation ◽  
Creep Fatigue ◽  
Fatigue Life Evaluation ◽  
Rational Evaluation

For the reliable operation of bellows under cyclic loadings at high temperatures, a rational evaluation method of life of bellows would be needed. Authors investigated simplified analysis methods for fatigue and creep-fatigue life prediction of U-shaped bellows considering inelasticity as well as various geometrical nonuniformity such as thickness and shape of convolutions. A conservative evaluation method of the strain range is developed, introducing three strain range amplification factors for nominal elastic strain range. Creep and relaxation behaviors of bellows are studied. Consequently, a new evaluation method of creep damage fractions is proposed which depends upon the relation between primary and secondary stresses. Fatigue and creep-fatigue tests are conducted and the validity of the present methods is discussed.

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