Non-Symmetrical Load Influence on Aluminum Alloy-Welded Joint Fatigue Limit

2011 ◽  
Vol 299-300 ◽  
pp. 412-416
Author(s):  
Hua Zou ◽  
Qiang Li ◽  
Shou Guang Sun
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Limit ◽  
Stress Ratio ◽  
Welded Joint ◽  
Mean Stress ◽  
The Mean ◽  
Limit Amplitude ◽  
Symmetrical Load

The mean stress caused by a non-symmetrical load significantly influences the fatigue limit. The fatigue limit of an aluminum alloy-welded joint is analyzed in the present paper using a stress ratio of 0.3. Our results show that the aluminum alloy-welded joint fatigue limit amplitude can be accurately converted from the mean stress using the Goodman beeline and Eurocode9 methods.

High-Cycle Fatigue Behavior of Type 4340 Steel Pressurized Blocks Including Mean Stress Effect

2019 ◽  
Author(s):  
Elie A. Badr ◽  
Joanne Ishak
Keyword(s):  
Stress Ratio ◽  
Fatigue Behavior ◽  
Fatigue Loading ◽  
Fatigue Tests ◽  
Ultimate Stress ◽  
Stress Effect ◽  
Mean Stress ◽  
Test Results ◽  
Linear Correction ◽  
The Mean

Abstract Mean stress effects in pressurized steel blocks were examined under constant amplitude fatigue loading. The tests were performed to provide experimental data needed to study the effect of mean stress on fatigue lives of subject specimen, and to substantiate the use of analytical expressions to account for the mean stress. The mean stress was the result of subjecting the specimens to an autofrettage pressure which induced compressive residual stresses at the crossbore intersection of the specimens. Fatigue tests were carried out under both tensile and compressive mean stress levels. Test results were compared to several mean stress accounting relationships such as the Smith-Watson Topper, Bergmann and Seeger, modified Goodman, Gerber and Soderberg. Test results indicated that the modified Goodman equation is favorable in accounting for the effect of both tensile and compressive mean stresses on fatigue life (up to a compressive mean stress to ultimate stress ratio of −0.2). The behavior under compressive mean stress to ultimate stress ratio of less than −0.2 indicated that a linear correction relationship was required.

Evaluation of Conventional Al 2024 Fatigue Limit in Fatigue Test Using Thermographic Measurement: Effect of Frequency

2014 ◽  
Vol 891-892 ◽  
pp. 1308-1313
Author(s):  
Stanislav Seitl ◽  
Jan Klusák ◽  
Fernández Pelayo ◽  
Alfonso Canteli
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Limit ◽  
Fatigue Test ◽  
Stress Ratio ◽  
Load Control ◽  
Practical Applications ◽  
Thermographic Measurement ◽  
Al 2024

The reliability of the conventional fatigue limit estimation of aluminum alloy Al 2024 provided by thermographic measurements according to the Risitano method is investigated in order to check their validity for practical applications. With this aim, an experimental fatigue program on Al 2024 specimens under load control using a stress ratio R = 0.1 is performed at three different frequencies. The fatigue limit methodologies is first determined according to the methodologies proposed by Risitano et al. and Canteli et al., and then compared with that resulting from the conventional Wöhler curve.

scholarly journals OS0612 Fatigue Limit Estimation Considering Influence of the Mean Stress

2013 ◽  
Vol 2013 (0) ◽  
pp. _OS0612-1_-_OS0612-3_
Author(s):  
Keisuke HAYABUSA ◽  
Hiroaki AKAMOTO
Keyword(s):  
Fatigue Limit ◽  
Mean Stress ◽  
The Mean

Fatigue Limit Improvement by Needle-Peening for Stainless Steel Welded Joint Containing a Crack-Like Defect

2016 ◽  
Author(s):  
Ryutaro Fueki ◽  
Koji Takahashi
Keyword(s):  
Stainless Steel ◽  
Fatigue Limit ◽  
Stress Ratio ◽  
Welded Joint ◽  
Circular Crack ◽  
Fatigue Tests ◽  
Bending Fatigue ◽  
Circular Slit ◽  
High Fatigue ◽  
Weld Toe

The effects of needle-peening on the bending fatigue limit of an austenitic stainless steel JIS-SUS316 welded joint containing an artificial semi-circular slit on the weld toe were investigated. Peening was applied to specimens with a semi-circular slit at depths of a = 1.0 mm and 1.5 mm. Then, plane bending fatigue tests were carried out at a stress ratio of R = 0. The fatigue limits of welded specimens containing a semi-circular slit were increased for the peened specimens. Peened specimens with slit sizes of a = 1.0 mm had high fatigue limits that were nearly equal to those of non-slit, peened specimens. We observed that a semicircular slit with a depth of less than a = 1.0 mm could be rendered harmless by peening. Additionally, the values of fatigue limit and the maximum depth of a semi-circular slit that can be rendered harmless by peening were predicted based on fracture mechanics, where we assume that a semi-circular slit is equivalent to a semi-circular crack. The prediction results were consistent with experimental results.

Mean Stress Correction of S45C Carbon Steel Based on Crack Growth Concept

2020 ◽  
Author(s):  
Masayuki Kamaya
Keyword(s):  
Fatigue Life ◽  
Carbon Steel ◽  
Crack Growth ◽  
Fatigue Limit ◽  
Stress Amplitude ◽  
Strain Range ◽  
Good Prediction ◽  
Stress Effect ◽  
Mean Stress ◽  
The Mean

Abstract Influence of the mean stress on fatigue life and fatigue limit was investigated for carbon steel. Uni-axial fatigue tests were conducted under stress and strain-controlled conditions at room temperature. The fatigue life and fatigue limit were reduced by applying the mean stress for the same stress amplitude. The fatigue life exhibited a better correlation with the strain range than the stress amplitude did. Increase in strain range caused by applying the mean stress correlated well with the decrease in the fatigue life. It was assumed that the mean stress effect on the fatigue life was brought about by the change in crack growth rate caused by applying the mean stress. The mean stress enhanced crack mouth opening and accelerated the crack growth. The reduction in the fatigue limit was also brought about by the same effect. It was shown that the effective strain range gave good prediction of fatigue life and fatigue limit with and without the mean stress.

scholarly journals Statistical properties of cell stresses in 2D granular solids

2021 ◽  
Vol 249 ◽  
pp. 02006
Author(s):  
Takashi Matsushima ◽  
Raphael Blumenfeld
Keyword(s):  
Stress Ratio ◽  
Cell Structure ◽  
External Pressure ◽  
Cell Stress ◽  
Mean Stress ◽  
Coordination Numbers ◽  
Granular Solids ◽  
Granular Assemblies ◽  
Cell Structures ◽  
The Mean

We investigate numerically the statistics of the stresses, defined for cells - the irreducible loops surrounded by particles in contact - in two-dimensional granular solids and the relation between these cell stresses and cell structures. We prepared a number of mechanically stable granular assemblies at various packing fractions and mean coordination numbers, and measured the stress statistics on each cell. We find the following. (1) The mean cell stress agrees with the bulk external pressure; (2) the probability density function of the normalised cell stress ratio collapses into a master curve; (3) the mean stress ratio increases with increasing intergranular friction; (4) the mean stress ratio per cell order decreases with increasing cell order because of their reduced stability; (5) the maximum cell stress direction correlates well with the cell’s long axis. These results are strong evidence that the cell structure and the stress field self-organise together and reveal the co-evolving correlations between the two.

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