The mean stress effect on the high-cycle fatigue strength from a multiaxial fatigue point of view

2005 ◽  
Vol 27 (8) ◽  
pp. 928-943 ◽  
Author(s):  
L SUSMEL ◽  
R TOVO ◽  
P LAZZARIN
Keyword(s):  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Multiaxial Fatigue ◽  
Point Of View ◽  
Stress Effect ◽  
Mean Stress ◽  
Cycle Fatigue ◽  
Mean Stress Effect ◽  
The Mean

scholarly journals Multiaxial fatigue life estimation in low-cycle fatigue regime including the mean stress effect

2018 ◽  
Vol 165 ◽  
pp. 16002
Author(s):  
Daniela Scorza ◽  
Andrea Carpinteri ◽  
Giovanni Fortese ◽  
Camilla Ronchei ◽  
Sabrina Vantadori ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Equivalent Strain ◽  
Mean Value ◽  
Multiaxial Fatigue ◽  
Stress Effect ◽  
Mean Stress ◽  
Cycle Fatigue ◽  
Structural Components ◽  
Mean Stress Effect

The goal of the present paper is to discuss the reliability of a strain-based multiaxial Low-Cycle Fatigue (LCF) criterion in estimating the fatigue lifetime of metallic structural components subjected to multiaxial sinusoidal loading with zero and non-zero mean value. Since it is well-known that a tensile mean normal stress reduces the fatigue life of structural components, three different models available in the literature are implemented in the present criterion in order to take into account the above mean stress effect. In particular, such a criterion is formulated in terms of strains by employing the displacement components acting on the critical plane and, then, by defining an equivalent strain related to such a plane. The Morrow model, the Smith-Watson-Topper model and the Manson-Halford model are applied to define such an equivalent strain. The effectiveness of the new formulations is evaluated through comparison with some experimental data reported in the literature, related to biaxial fatigue tests performed on metallic specimens under in-and out-of-phase loadings characterised by non-zero mean stress values.

scholarly journals Mean stress effect under Multi-Axial High Cycle Fatigue loading for cast A356-T6 alloy

2014 ◽  
Vol 12 ◽  
pp. 04025
Author(s):  
M. Iben Houria ◽  
Y. Nadot ◽  
R. Fathallah ◽  
M.J. Roy ◽  
D.M. Maijer
Keyword(s):  
High Cycle Fatigue ◽  
Fatigue Loading ◽  
Stress Effect ◽  
Mean Stress ◽  
Cycle Fatigue ◽  
Mean Stress Effect

scholarly journals Application of the S-N Curve Mean Stress Correction Model in Terms of Fatigue Life Estimation for Random Torsional Loading for Selected Aluminum Alloys

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2985
Author(s):  
Michał Böhm ◽  
Krzysztof Kluger ◽  
Sławomir Pochwała ◽  
Mariusz Kupina
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Stress Effect ◽  
Mean Stress ◽  
Torsional Loading ◽  
Correction Model ◽  
Life Estimation ◽  
Mean Stress Effect ◽  
Fatigue Life Estimation ◽  
The Mean

The paper presents the experimental fatigue test results for cyclic constant amplitude loading conditions for the case of the torsion of the PA4 (AW-6082-T6), PA6 (AW-2017A-T4) and PA7 (AW-2024-T3) aluminum alloy for a drilled diabolo type test specimen. The tests have been performed for the stress asymmetry ratios R = −1, R = −0.7, R = −0.5 and R = −0.3. The experimental results have been used in the process of a fatigue life estimation performed for a random generated narrowband stress signal with a zero and a non-zero global mean stress value. The calculations have been performed within the time domain with the use of the rainflow cycle counting method and the Palmgren−Miner damage hypothesis. The mean stress compensation has been performed with the S-N curve mean stress model proposed by Niesłony and Böhm. The model has been modified in terms of torsional loading conditions. In order to obtain an appropriate R = 0 ratio S-N curve fatigue strength amplitude, the Smith−Watson−Topper model was used and compared with literature fatigue strength amplitudes. The presented solution extends the use of the correction model in terms of the torsional loading condition in order to obtain new S-N curves for other R values on the basis of the R = −1 results. The work includes the computational results for new fatigue curves with and without the mean stress effect correction. The results of the computations show that the mean stress effect plays a major role in the fatigue life assessment of the tested aluminum alloys and that the method can be used to assess the fatigue life under random conditions.

Novel Modeling of Mean Stress Effect on the High-Cycle Fatigue Performance of Preloaded Threaded Fasteners

2019 ◽  
Author(s):  
Sayed A. Nassar ◽  
Tianwu Li
Keyword(s):  
Experimental Data ◽  
High Cycle Fatigue ◽  
High Strength ◽  
Fatigue Performance ◽  
Stress Effect ◽  
Mean Stress ◽  
Cycle Fatigue ◽  
Mean Stress Effect ◽  
Threaded Fasteners ◽  
Proposed Model

Abstract An experimentally validated model is proposed for the effect of fastener mean stress on its high cycle fatigue (HCF) performance. The model is also used for comparing fatigue performance of ultra-high strength (UHS) fasteners Class 14.8, 15.8 and 16.8 with that of commercially available (CA) Class 10.9 and 12.9 fasteners. Respective mean stress-adjusted S-N curves are constructed using experimental data following applicable ASTM standards. Proposed model results are compared with other existing models that account for the effect of mean stress such as Goodman, Gerber, Morrow, Soderberg, and Elliptic (ASME) models. Detailed discussion of the results, failure mode, and conclusions are provided.

Mean Stress Effect on Fatigue of Welded Joint in FPSOs

2006 ◽  
Author(s):  
Bin Zhang ◽  
Torgeir Moan
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Stress Effect ◽  
Mean Stress ◽  
Initial Condition ◽  
Mean Stress Effect ◽  
Structural Details ◽  
The Mean ◽  
Mean Stresses

This paper deals with the mean stress effect on the fatigue life of welded joints in FPSOs. Mean stresses in structural details of FPSOs are composed of residual stresses and mean stresses induced by external service loading conditions. Mean stresses, both the residual stresses and those induced by external load, affect on the fatigue life of structural details. Fatigue strength decreases as tensile mean stress increases. Under compressive mean stresses, fatigue lives are increased. Different fatigue analysis procedures to account for mean stress effect, i.e. JBP, JTP, DNV CN30.7 and IIW procedure, are used to compare the fatigue test data of different specimens representing different typical welded connections in ship-shaped structures from HHI in Korea. In this paper these procedures are compared and an improved procedure explicitly considering of the mean stress effect is also proposed. The fatigue strength of welded joints of FPSO is affected by the initial condition as well as possible redistribution (shake-down) of the residual stresses. The initial condition of welding residual stress and its re-distribution by static preload and cyclic load in the small scale specimens are evaluated with FE analyses and analytical equations, also compared with the test results obtained from measurement based on ordinary sectioning method.

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