scholarly journals Fatigue Strength Reduction Factor of Mild and High Strength Steels

1977 ◽  
Vol 1977 (141) ◽  
pp. 257-267 ◽  
Author(s):  
Kunihiro Iida ◽  
Yunbo Kho
Keyword(s):  
Fatigue Strength ◽  
High Strength Steels ◽  
High Strength ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor

Design of Pressure Vessels for Low-Cycle Fatigue

1962 ◽  
Vol 84 (3) ◽  
pp. 389-399 ◽  
Author(s):  
B. F. Langer
Keyword(s):  
Fatigue Strength ◽  
Pressure Vessel ◽  
Low Cycle Fatigue ◽  
Fatigue Curve ◽  
Pressure Vessels ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
The Mean ◽  
Fatigue Evaluation

Methods are described for constructing a fatigue curve based on strain-fatigue data for use in pressure vessel design. When this curve is used, the same fatigue strength-reduction factor should be used for low-cycle as for high-cycle conditions. When evaluating the effects of combined mean and alternating stress, the fatigue strength-reduction factor should be applied to both the mean and the alternating component, but then account must be taken of the reduction in mean stress which can be produced by yielding. The complete fatigue evaluation of a pressure vessel can be a major task for the designer, but it can be omitted, or at least drastically reduced, if certain requirements can be met regarding design details, inspection, and magnitude of transients. Although the emphasis in this paper is on pressure vessel design, the same principles could be applied to any structure made of ductile metal and subjected to limited numbers of load cycles.

Fatigue life evaluation of an ultrafine-grained pure aluminum

2019 ◽  
Vol 234 (1) ◽  
pp. 90-104
Author(s):  
Alireza Babaei ◽  
Firooz Esmaeili-Goldarag ◽  
Hossein Jafarzadeh
Keyword(s):  
Fatigue Strength ◽  
Fatigue Behavior ◽  
Pure Aluminum ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
Dislocation Dynamic ◽  
Constitutive Material Model ◽  
Ultrafine Grained ◽  
Cyclic Extrusion Compression

The aim of this study is an experimental and numerical investigation of the fatigue behavior of a notched ultrafine-grained pure aluminum processed by strip cyclic extrusion-compression method. In this regard, the fatigue experiments were conducted for the unprocessed and strip cyclic extrusion-compression processed specimens under various cyclic loads. In the numerical analyses, a dislocation dynamic constitutive material model which tracks the microstructure evolution was implemented for numerical estimation of the values of fatigue strength reduction factor via the volumetric approach. Considering the three-dimensional effect near the plate hole, the variation of the fatigue notch factor through the thickness of the plate was investigated and the obtained results showed that maximum fatigue strength reduction factor was occurred in the middle of the plate due to the symmetry of specimen geometry and loading condition. The investigation reveals a good agreement between the numerical and experimental lives. The results showed although the smooth processed specimens have higher fatigue strength in comparison of the unprocessed ones, the notched processed specimens have lower fatigue strength in comparison of the unprocessed ones.

346 Fatigue Strength Reduction Factor of Notched Plates subjected to Cyclic Bending Load

2001 ◽  
Vol 2001 (0) ◽  
pp. 323-324
Author(s):  
Yoshio FUKUDA ◽  
Masakazu KANOU ◽  
Satoshi SUKEGAWA ◽  
Kazuya WATANABE ◽  
Ryukichi KENJOU
Keyword(s):  
Fatigue Strength ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
Cyclic Bending ◽  
Bending Load

Analytical Study on Fatigue Strength Reduction Factor of Small-Diameter Socket-Welded Pipe Joints

1998 ◽  
Vol 120 (2) ◽  
pp. 157-163 ◽  
Author(s):  
M. Higuchi ◽  
A. Nakagawa ◽  
K. Iida ◽  
M. Hayashi ◽  
T. Yamauchi ◽  
...  
Keyword(s):  
Residual Stress ◽  
Fatigue Strength ◽  
Welded Joints ◽  
Small Diameter ◽  
Large Change ◽  
Fatigue Tests ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
Welded Pipe

Four-point bending and rotating bending fatigue tests were conducted on socket-welded joints made of carbon, stainless, and Cr-Mo steels for clarification of the effects of diameter, welding pass sequence and post-weld heat treatment (PWHT) on fatigue strength. The results were evaluated quantitatively. Fatigue strength of socket-welded joints was found to strongly depend on weld pass sequences in fillet welds, this being possibly due to large change in residual stress distribution at roots and toes. The effects of residual stress were thus examined quantitatively by comparison of fatigue strength of PWHT stress-free specimens with that of as-welded specimens. By the modified Goodman’s method, the lowest S-N curve corresponding to maximum tensile residual stress and the highest S-N curve corresponding to maximum compression residual stress were obtained for different steels and diameters. Conventional S-N data of socket-welded joints were situated between these two limiting curves. Based on the lowest curve, fatigue strength reduction factors of socket-welded joints were proposed.

A Probabilistic Model of Size Effect in the Fatigue Strength of Rounds in Bending and Torsion

1980 ◽  
Vol 102 (1) ◽  
pp. 32-37
Author(s):  
C. R. Mischke
Keyword(s):  
Fatigue Strength ◽  
Probabilistic Model ◽  
Fatigue Tests ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Probabilistic Design ◽  
Strength Reduction Factor ◽  
Design Procedures ◽  
Endurance Strength ◽  
The Mean

The use of a probabilistic premise to establish the relation of size to the attenuation of endurance strength in rounds, such as shafts subjected to bending or torsion is investigated. The method allows the designer to construct the appropriate expression for Marin fatigue strength reduction factor, kb, directly from fatigue tests that have been ordered. For probabilistic design procedures, the mean and standard deivation of the Marin fatigue strength reduction factor are required, and the method described allows these estimates to be made.

Fatigue Strength Reduction Factors for Socket Welds as a Function of Leg Length

2011 ◽  
Author(s):  
Paul Hirschberg ◽  
Andrew M. Crompton ◽  
Robert Dana Couch
Keyword(s):  
Fatigue Strength ◽  
Nuclear Power ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Leg Length ◽  
Strength Reduction Factor ◽  
Standard Size ◽  
Butt Weld ◽  
Testing Program ◽  
Minimum Requirement

Socket welds in nuclear power plant piping systems have had a history of failure due to high cycle fatigue. Cyclic bending loads, typically from vibration, have caused cracking either at the weld root or at the toes. A testing program was conducted to measure the effectiveness of proposed changes in socket weld geometry and fabrication [3]. One of the significant results of that testing program was that if the socket weld profile was modified such that the weld leg length along the pipe side is at least double the Code minimum requirement the fatigue life of the weld becomes approximately as good as that of a butt weld. The test results demonstrated that the fatigue strength reduction factor (FSRF) is about 37% smaller for socket welds with the longer weld leg, than for a standard size weld. Many plants have been replacing or building up their socket welds in locations susceptible to vibration to the 2×1 geometry to take advantage of the improved fatigue strength. However, there have been situations where welds were built up from the Code minimum, but inspections determined that the leg length was somewhat less than twice the minimum required and the weld was not accepted as meeting the 2×1 geometry. It is not known how the fatigue strength reduction factor would vary as a function of leg length for intermediate sizes. It is also of interest to determine the effect of increasing the weld leg length on the fitting side. For example, is it possible that increased fatigue resistance can be provided by adding additional leg length on the fitting side instead of the pipe side, or can a greater benefit be achieved if they were provided on both sides?

Decreasing the Fatigue Strength Reduction Factor by Dimpling

1974 ◽  
Vol 2 (5) ◽  
pp. 425 ◽  
Author(s):  
SF Etris ◽  
YR Fiorini ◽  
KC Lieb ◽  
IC Moore ◽  
AL Batik ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor
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