scholarly journals Effects of specimen size on fatigue life of metallic materials in high-cycle and very-high-cycle fatigue regimes

2016 ◽  
Vol 39 (6) ◽  
pp. 770-779 ◽  
Author(s):  
C. Sun ◽  
X. Zhang ◽  
X. Liu ◽  
Y. Hong
Keyword(s):  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Specimen Size ◽  
Metallic Materials ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Very High

The Effects of Specimen Size on the Very High Cycle Fatigue Properties of FV520B-I

2015 ◽  
Author(s):  
Ming Zhang ◽  
Weiqiang Wang ◽  
Aiju Li
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Specimen Size ◽  
Fatigue Properties ◽  
Test Results ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Heat Effects ◽  
Very High

The authors researched the effects of specimen size on the very high cycle fatigue properties of FV520B-I through ultrasonic fatigue testing. The test results showed that the very high cycle fatigue mechanism was not changed and the fatigue properties declined as the specimen size increased. The S-N curve moved downward and the fatigue life decreased under the same stress level maybe due to the heat effects of large specimens in tests. The fatigue strength and the fatigue life were predicted by relevant models. The prediction of fatigue strength was close to test result, and the prediction of fatigue life was less effective compared with the previous prediction of small size specimen test results.

Prediction of the fatigue life of VT1-0 titanium in various structural states under very high cycle fatigue

2021 ◽  
Vol 11 (4) ◽  
pp. 422-426
Author(s):  
Dmitry Ledon ◽  
Mikhail Bannikov ◽  
Vladimir Oborin ◽  
Yuriy Bayandin ◽  
Oleg Naimark
Keyword(s):  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Very High

Review on Surface Failure Mode of Metallic Materials in Very High Cycle Fatigue Regime

2014 ◽  
Vol 902 ◽  
pp. 66-69
Author(s):  
Wei Li
Keyword(s):  
High Cycle Fatigue ◽  
Surface Finishing ◽  
Surface Roughening ◽  
Metallic Materials ◽  
Cycle Fatigue ◽  
Surface Failure ◽  
Very High Cycle Fatigue ◽  
Metallurgical Defects ◽  
Type Size ◽  
Very High

With higher cleanness upgraded steadily, surface failure of metallic materials in very high cycle fatigue (VHCF) regime beyond 107 cycles has been reported one after another. The occurrence of surface crack initiation to failure in VHCF regime is closely related to the following factors: (i) surface finishing condition of specimen, i.e. whether some grinding scratches, grooves and cavities with a relatively larger size than the subsurface defect exist at the surface of specimen; (ii) type, size, location, distribution and density of metallurgical defects such as inclusion contained in the subsurface of material; (iii) degree of persistent slip band (PSB) deformation induced by surface roughening of specimen, mainly corresponding to the some ductile single-phase metallic materials.

scholarly journals Effect of Carburizing and Nitriding on Fatigue Properties of 18Cr2Ni4WA Steel in Very High Cycle Fatigue Regime

2021 ◽  
Vol 45 (3) ◽  
pp. 207-215
Author(s):  
Zhenduo Sun ◽  
Dongbo Hou ◽  
Wei Li
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
High Cycle Fatigue ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Internal Defect ◽  
Surface Fatigue ◽  
Very High Cycle Fatigue ◽  
The Relationship ◽  
Very High

The work aims to study the influence of carburizing and nitriding on fatigue properties of 18Cr2Ni4WA high strength steel in very high cycle fatigue regime. Very high cycle fatigue tests were carried out on 18Cr2Ni4WA Steel after carburizing and nitriding respectively. The micro morphology of fatigue fracture was observed by scanning electron microscope, the failure mode and failure mechanism were discussed. The relationship between fatigue life and defect size, FGA size, fish eye size of fracture was analyzed. The characteristic size of defects is evaluated by Gumbel, Weibull and GEV distribution functions, and a modified Akiniwa fatigue life prediction model considering the relationship between FGA size and inclusion size was established. The results showed that, nitriding and carburizing treatment improve the surface fatigue limit of the steel. The fatigue life decreases with the increase of internal defect size and FGA size. After carburizing and nitriding treatment, the internal fatigue strength of the specimen decreases slightly. When the failure probability is 99%, the internal defect sizes of nitrided specimens calculated by Weibull, Gumbel and GEV distributions are 141.5 μm, 148.4 μm and 211.7 μm respectively. The calculated internal defect sizes of carburized specimens are 47 μm, 67.8 μm and 40 μm respectively. Compared with the experimental data, the fatigue strength predicted by GEV is the most appropriate. carburizing and nitriding treatment can improve the surface fatigue strength of 18Cr2Ni4WA steel, but slightly reduce the internal fatigue strength. The prediction result of the new model is conservative when the failure probability is 99%, which is suitable for engineering application.

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