scholarly journals Mean stress effects on high-cycle fatigue of Alloy 718

1980 ◽  
Author(s):  
G E Korth
Keyword(s):  
High Cycle Fatigue ◽  
Mean Stress ◽  
Alloy 718 ◽  
Cycle Fatigue ◽  
Stress Effects

scholarly journals High-Cycle Fatigue Behaviour of Pure Tantalum under Multiaxial and Variable Amplitude Loadings

2014 ◽  
Vol 891-892 ◽  
pp. 1341-1346
Author(s):  
David Marechal ◽  
Nicolas Saintier ◽  
Thierry Palin-Luc ◽  
François Nadal
Keyword(s):  
High Cycle Fatigue ◽  
Fatigue Behaviour ◽  
Fracture Mechanisms ◽  
Mean Stress ◽  
Cycle Fatigue ◽  
Stress Effects ◽  
Military Applications ◽  
Stress Damage ◽  
Damage Rule ◽  
Pure Tantalum

Due to its specific mechanical properties, tantalum is often used in strength-demanding military applications. High-cycle fatigue (HCF) behaviour of pure tantalum, however, has been rarely reported and the mechanisms at stake to account for deformation under cyclic loadings are still badly understood. This paper aims at better understanding the fatigue behaviour of tantalum and at clarifying the mechanisms of damage formation encountered under such loadings. HCF experiments performed at room temperature on commercially-pure tantalum are presented. Mean stress effects were investigated in the aim of clarifying the interaction between fatigue and creep. Fracture mechanisms were observed to vary from intergranular to transgranular depending on applied stress amplitude and mean stress. Damage mechanisms were investigated under tension and torsion. Results are analyzed in the light of existing fatigue criteria, the limitations of which are discussed. Finally, complex sequential loadings, representative of in-service loadings, were applied to tantalum smooth specimens. The contribution of each loading sequence to the overall damage was quantified and analyzed in terms of linear or non-linear cumulative damage rule.

Safety Factor in Fatigue Under Fluctuating Stresses

1987 ◽  
Vol 109 (4) ◽  
pp. 397-401 ◽  
Author(s):  
V. A. Avakov
Keyword(s):  
Safety Factor ◽  
High Cycle Fatigue ◽  
Stress Amplitude ◽  
Static Strength ◽  
Mean Stress ◽  
Cycle Fatigue ◽  
Safety Factors ◽  
Generalize Expression ◽  
Allowable Stresses ◽  
Number Of Cycles

It is common to assume identical allowable safety factors in static strength [m], defined by mean stress (Sm), and in fatigue [a], defined by stress amplitude (Sa), in order to find the full safety factor (F) under asymmetrical cycles, or to plot any type of the Sm–Sa diagram of allowable stresses. Here additional modification is considered to generalize expression of the full factor of safety in fatigue under asymmetrical stresses, utilizing unequal allowable safety factors in static strength (by mean stress) and in fatigue (by stress amplitude): ([a] ≠ [m]). We assume that loading is stationary, and cumulated number of cycles is large enough to consider high cycle fatigue.

scholarly journals The effect of mean stress and stress biaxiality in high-cycle fatigue

2017 ◽  
Vol 41 (2) ◽  
pp. 440-455 ◽  
Author(s):  
Imade Koutiri ◽  
Daniel Bellett ◽  
Franck Morel
Keyword(s):  
High Cycle Fatigue ◽  
Mean Stress ◽  
Cycle Fatigue
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