Notch Effect in Biaxial Low Cycle Fatigue at Elevated Temperatures

1989 ◽  
Vol 111 (3) ◽  
pp. 286-293 ◽  
Author(s):  
H. Umeda ◽  
M. Sakane ◽  
M. Ohnami

This paper describes the notch effect in biaxial low cycle fatigue of an austenitic stainless steel SUS 304 at 873K in air. Mises’ equivalent stress controlled fatigue tests were carried out for the three kinds of round notched specimens in push-pull/torsion biaxial stress states. Cracks emanated at the notch root were measured by a d.c. potential drop method. Reduction in the fatigue life due to the notch was most significant in the reversed torsion test in comparison with the push-pull and combined push-pull/reversed torsion tests. The conventional fatigue life prediction methods, i.e., the Neuber’s rule, the Stowell’s method, and the Koe’s method, were applied to the experimental data and the accuracy of the prediction methods were discussed.

2011 ◽  
Vol 35 (7) ◽  
pp. 753-758 ◽  
Author(s):  
Ho-Young Yang ◽  
Jae-Hoon Kim ◽  
Keun-Bong Yoo ◽  
Han-Sang Lee ◽  
Young-Soo You

1970 ◽  
Vol 92 (1) ◽  
pp. 86-92 ◽  
Author(s):  
H. V. Cordiano

A determination was made of the influence of various mechanical finishing procedures on residual stresses and the resulting effect on the low cycle fatigue life of tee-fillet welds in 1-1/2 in. thick rolled steel plate with a yield strength of 80,000 psi. Included in this work were tee-fillet welds in the as-welded, ground, shot-peened, ground and shot-peened, and mechanically peened condition. Residual stresses were measured by a hole drilling technique developed at the Naval Applied Science Laboratory for application to linearly varying biaxial stress fields. This method has been found suitable for determining residual stresses at any point over a limited area at the toe of the weld. Fatigue tests were conducted on plate type specimens, 32 in. by 29 in. by 1-1/2 in. which were simply supported at two edges, free at the other two edges, and uniformly loaded with compressed air to develop a zero to maximum tension range of stress at the toe of the fillet weld. It was found that tensile residual stresses do not have a significant effect on fatigue life for the type of pulsating load used. Compressive residual stresses have been found to have a beneficial effect on fatigue life. Welds with relatively high residual stresses which were ground smooth to eliminate “stress raisers” showed very good fatigue resistance.


2011 ◽  
Vol 60 (9) ◽  
pp. 803-810
Author(s):  
Taejoon KIM ◽  
Yuki WATANABE ◽  
Shengde ZHANG ◽  
Masao SAKANE

1986 ◽  
Vol 108 (4) ◽  
pp. 279-284 ◽  
Author(s):  
Masao Sakane ◽  
Masateru Ohnami

This paper describes the notch effect in low-cycle fatigue of an austenitic stainless steel SUS 304 at 873 K in air. Total strain range-controlled tests were carried out using a round unnotched and three round notched specimens. A prediction method for low-cycle fatigue lives of notched specimens was developed by predicting the crack initiation and propagation periods separately. To predict the former Neuber’s rule was applied and a nominal stress/strain criterion was developed to predict the latter. Failure lives, obtained by adding the two prediction lives, closely agree with observed failure lives.


2004 ◽  
Vol 261-263 ◽  
pp. 1135-1140 ◽  
Author(s):  
Keum Oh Lee ◽  
Sam Son Yoon ◽  
Soon Bok Lee ◽  
Bum Shin Kim

In recent, ferritic stainless steels are widely used in high temperature structure because of their high resistance in thermal fatigue and low prices. Tensile and low cycle fatigue(LCF) tests on 429EM stainless steel were performed at several temperatures from room temperature to 600°C. Elastic modulus, yield stress and ultimate tensile strength(UTS) decreased with increasing temperature. Considerable cyclic hardening occurred at 200°C and 400°C. 475°C embrittlement observed could not explain this phenomenon but dynamic strain aging(DSA) observed from 200°C to 500°C could explain the hardening mechanism at 200°C and 400°C. And it was observed that plastic strain energy density(PSED) was useful to predict fatigue life when large cyclic hardening occurred. Fatigue life using PSED over elastic modulus could be well predicted within 2X scatter band at various temperatures.


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