Closure to “Discussions of ‘Dynamic Capacity and Surface Fatigue Life for Spur and Helical Gears’” (1976, ASME J. Lubr. Technol., 98, pp. 275–276)

1976 ◽  
Vol 98 (2) ◽  
pp. 276-276
Author(s):  
J. J. Coy ◽  
D. P. Townsend ◽  
E. V. Zaretsky
Keyword(s):  
Fatigue Life ◽  
Helical Gears ◽  
Dynamic Capacity ◽  
Surface Fatigue

scholarly journals Dynamic Capacity and Surface Fatigue Life for Spur and Helical Gears

1976 ◽  
Vol 98 (2) ◽  
pp. 267-274 ◽  
Author(s):  
J. J. Coy ◽  
D. P. Townsend ◽  
E. V. Zaretsky
Keyword(s):  
Fatigue Life ◽  
Gear Train ◽  
Rolling Element Bearing ◽  
Tangential Load ◽  
Dynamic Capacity ◽  
Probability Of Survival ◽  
Surface Fatigue ◽  
Rolling Element ◽  
Life Model ◽  
Life Predictions

A mathematical model for surface fatigue life of gear, pinion, or entire meshing gear train is given. The theory is based on the statistical approach used by Lundberg and Palmgren for rolling-element bearings. Also equations are presented which give the dynamic capacity of the gear set. The dynamic capacity is the transmitted tangential load which gives a 90 percent probability of survival of the gear set for one million pinion revolutions. The analytical results were compared with test data for a set of AISI 9310 spur gears operating at a maximum Hertz stress of 1.71 × 109 N/m2 (248,000 psi) and 10,000 rpm. The theoretical life predictions were very good when material constants obtained from rolling-element bearing tests were used in the gear life model.

Fatigue Failure and Strength Evaluation of Traction Drive Rollers

2000 ◽  
Author(s):  
Masana Kato ◽  
Gang Deng ◽  
Masashi Yamanaka ◽  
Ryoji Yamamoto ◽  
Noboru Ono ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Crack Growth ◽  
Surface Crack ◽  
Traction Force ◽  
Fatigue Tests ◽  
Slip Ratio ◽  
Traction Drive ◽  
Surface Fatigue ◽  
Surface Crack Growth

Abstract The surface fatigue failures of the traction drive rollers are different to that of gears and bearings because of the high traction force, skew and small slip ratio. In this research, fatigue tests of traction rollers were performed in different slip ratios and skew angles. The effects of running conditions on the fatigue lives of traction drive rollers are clarified and explained based on the surface crack growth and wear situations. Although a higher slip ratio will make a lower fatigue life, the fatigue strength will increase inversley under the skew conditions, because of the differences in mechanical and tribological condition for surface crack growth and the severe surface wear, which diminishes the surface crack length. For evaluation of the effects of such as slip ratio and skew on the fatigue strength of traction rollers, a new method is put forward in which the relationship between the surface temperature index and fatigue life is used instead of S-N curve.

Metal Surface Fatigue Detection Using Nonlinear Ultrasonic

2014 ◽  
Vol 510 ◽  
pp. 156-162 ◽  
Author(s):  
Hong Juan Yan ◽  
Chun Guang Xu ◽  
Qi Lin ◽  
Hai Chao Cai
Keyword(s):  
Fatigue Life ◽  
Nonlinear Coefficient ◽  
304 Stainless Steel ◽  
2024 Aluminum Alloy ◽  
Surface Fatigue ◽  
Micro Cracks ◽  
Nonlinear Ultrasonic ◽  
Ultrasonic Propagation ◽  
Fatigue Detection ◽  
The Relationship

Based on theory of ultrasonic nondestructive testing on surface fatigue damage of metal components, the wave law of ultrasonic nonlinearity caused by fatigue is studied. When there are lattice defects in metal material, second-order nonlinear coefficient β changes during ultrasonic propagation. According to the point, the system of nonlinear ultrasonic testing is build. The change trends of harmonic amplitudes and ultrasonic coefficients are measured during fatigue bending testing of materials such as 45 steel, 2024 aluminum alloy and 304 stainless steel. The results shows: in elastic phase, the ratios of harmonic and fundamental waves monotonically increase with fatigue life, and in plastic phase, deformations appear and micro-cracks expand into macro-cracks in materials, the ratios firstly decrease and then increase with fatigue life. However the quadratic sums of nonlinear coefficient are approximately linear with the fatigue life. Therefore, when the relationship between the quadratic sums and fatigue life is known, it can be used to characterize fatigue state of metal materials.

Contact surface fatigue life for roller rack pinion system

2012 ◽  
Vol 19 (12) ◽  
pp. 3454-3459 ◽  
Author(s):  
Chang-hyun Kim ◽  
Heung-soap Choi ◽  
Soon-man Kwon
Keyword(s):  
Fatigue Life ◽  
Contact Surface ◽  
Surface Fatigue

Surface fatigue life of M50NiL and AISI 9310 gears and rolling-contact bars

1991 ◽  
Vol 7 (4) ◽  
pp. 642-649 ◽  
Author(s):  
Dennis P. Townsend ◽  
Eric N. Bamberger
Keyword(s):  
Fatigue Life ◽  
Rolling Contact ◽  
Surface Fatigue

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.

The Toroid Contact Roller Test as Applied to the Study of Bearing Materials

1962 ◽  
Vol 84 (1) ◽  
pp. 181-189 ◽  
Author(s):  
W. J. Greenert
Keyword(s):  
Heat Treatment ◽  
Shear Stress ◽  
Fatigue Life ◽  
Statistical Evaluation ◽  
Surface Fatigue ◽  
Aisi 52100 ◽  
Bearing Materials ◽  
Contact Surfaces ◽  
Contact Roller ◽  
Orthogonal Shear Stress

An understanding of the basic mechanics and statistical variables of the contact roller test as it is applied to surface fatigue phenomena was obtained. One hundred ninety-four contact rollers of AISI 52100 bearing quality steel were tested to establish dispersion limits. No significant fatigue differences were indicated for heats, bars, or test replications among steels of similar quality, composition, and heat-treatment. A statistical evaluation of results points to the contact roller test as a suitable means for studying significant variables that pertain to both the theoretical and material aspects of antifriction bearings. Stresses in the contact surfaces based on the orthogonal shear-stress theories showed good correlation with fatigue life.

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