A Shear-Stress Normal-Strain Cycle Relation to Fatigue in Bending, Torsion, and Rolling Contact

1970 ◽  
Vol 92 (4) ◽  
pp. 567-571 ◽  
Author(s):  
John Lyman
Keyword(s):  
Shear Stress ◽  
Stress Condition ◽  
Ball Bearing ◽  
High Strength ◽  
Rolling Contact ◽  
Normal Strain ◽  
Stress Cycle ◽  
Plastic Deformations ◽  
Strain Cycle ◽  
Prior Analysis

Previous work [4] has suggested a shear stress normal strain “potential” as a means of relating stress condition to fatigue of high-strength low-allow steels. Experimental data here permits the rationalization of the theory required in the prior analysis to be supported directly. An attempt is made to relate highly directed plastic deformations that have been observed in SKF 6309 ball bearing inner rings to directed shear-stress normal-strain configurations of the complex triaxial rolling contact stress cycle in the principal plane of rolling.

On Ratchetting-Based Models of Wear and Rolling Contact Fatigue (RCF)

2003 ◽  
Author(s):  
M. Ciavarella ◽  
L. Afferrante
Keyword(s):  
Shear Stress ◽  
Plastic Material ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Longitudinal Direction ◽  
Surface Flow ◽  
Rolling Contact ◽  
Stress Cycle ◽  
Shakedown Theory ◽  
Number Of Cycles

Recent efforts to develop simple unified models of both wear and RCF (Kapoor & Franklin, 2000, Franklin et al., 2001) are discussed, in view of previous theoretical and experimental results on ratchetting in rolling contact. At sufficiently high contact pressures, surfaces deform plastically with unidirectional cumulation of “ratchetting” strains (Johnson, 1985, Ch.9). However, the modelling of ratchetting strains as a function of plastic material properties has turned out more complicated than what originally suggested by the first attempts (Merwin & Johnson, 1963), as recently discussed by Ponter et al. (2003). Wear due to surface ratchetting occurs for sufficiently high friction, whereas RCF is mainly due to ratchetting subsurface. It appears that experimental data on ratchetting strains in the literature unfortunately do not show a clear and unique trend, and various proposed fitting equations differ significantly in quantitative and qualitative terms, particularly at large number of cycles. It is shown that ratchetting in rolling contact is a combination of “structural ratchetting” (that modelled with the perfect plasticity model) and “material ratchetting”, and the latter is very sensitive to the hardening behaviour of the material. Also, the surface and subsurface flow regimes are very different: in pure rolling, a simplified model of the stress cycle condition is a fully reversed cycle of shear superposed to an out-of-phase pulsating compression in a extended region below the surface (neglecting other two components also of pulsating compression); increasing the friction coefficient, a mean shear stress is induced as well as a tensile component in the direct stress, and for friction f > 0.3 the maximum moves at the surface, but the highly stressed zone becomes a thin surface layer which suffers uniquely of “material ratchetting”. In the limit of very high friction, we have the critical condition on the surface which obviously gives a pulsating shear stress cycle in phase with a pulsating compression, but in addition we have a nearly fully reversed cycle of tension-compression (although the tensile peak is very localized also in the longitudinal direction). Such multiaxial stress fields and their largely different features introduced cause a response of the material which has not been studied enough, perhaps both in terms of ratchetting rates and in terms of the failure condition. In particular, the ductility for ratchetting surface flow as used in wear models seems apparently much higher than that for RCF ratchetting models. Also, RCF at large number of cycles in the C&S experiments (Clayton & Su, 1996, Su & Clayton, 1997) seems not well correlated with shakedown theory, and accordingly, simple ratchetting equations based on excess of shakedown such as that of Tyfoor et al (1996), do not seem well suited a Wohler SN life curve. However, these conclusions are only very qualitative as the materials in the two tests are different, and at present empirical separate models for wear and RCF based on hardness of materials and a posteriori data fitting seem the only quantitative way forward for engineering purposes.

Investigations on the Mechanical Properties and Formability of Friction Stir Welded Tailored Blanks

2007 ◽  
Vol 344 ◽  
pp. 143-150 ◽  
Author(s):  
Gianluca Buffa ◽  
Livan Fratini ◽  
Marion Merklein ◽  
Detlev Staud
Keyword(s):  
Mechanical Properties ◽  
Stress Condition ◽  
Research Effort ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Friction Stir ◽  
Tailored Blanks ◽  
Sheet Stamping ◽  
Wide Range

Tight competition characterizing automotive industries in the last decades has determined a strong research effort aimed to improve utilized processes and materials in sheet stamping. As far as the latter are regarded light weight alloys, high strength steels and tailored blanks have been increasingly utilized with the aim to reduce parts weight and fuel consumptions. In the paper the mechanical properties and formability of tailored welded blanks made of a precipitation hardenable aluminum alloy but with different sheet thicknesses, have been investigated: both laser welding and friction stir welding have been developed to obtain the tailored blanks. For both welding operations a wide range of the thickness ratios has been considered. The formability of the obtained blanks has been characterized through tensile tests and cup deep drawing tests, in order to show the formability in dependency of the stress condition; what is more mechanical and metallurgical investigations have been made on the welded joints.

Plastic Analysis of Metal Sheet Forming with SD Effects

2013 ◽  
Vol 299 ◽  
pp. 216-220
Author(s):  
Zhen Yu Chen ◽  
Chun Du Wu ◽  
Zhong Xian Wang
Keyword(s):  
Shear Stress ◽  
Yield Criterion ◽  
High Strength ◽  
Sheet Forming ◽  
Metal Sheet ◽  
Film Stress ◽  
Strength Differential ◽  
Thin Film Stress ◽  
Plastic Analysis ◽  
Tension And Compression

Generally, many high-strength alloy materials used in aerospace, power and chemical industries have strength differential effect in tension and compression (SD effects). Usually, in mechanical calculations of sheet metal forming, Treasca yield criterion and Mises yield criterion are applied. Because the yield criterions don’t take SD effects into consideration, the calculation result may have errors for certain materials. However, generalized twin shear stress yield criterion, which takes into account the influence of the intermediate principal stress, is more suitable for most metal materials than Mohr-Coulomb strength theory. Therefore, this article has made plastic analysis on thin film stress issues of metal sheet forming with generalized twin shear stress yield criterion. We have obtained a unified plastic solution to the internal and external stretching issue of thin material with rounded holes and different tension and compression ratio. Providing a new result with wider applicability is very significant.

The Effect of Deformation on Mechanical Properties and Shakedown on Railroad Wheels

2014 ◽  
Author(s):  
Steven L. Dedmon ◽  
Takashi Fujimura ◽  
Daniel Stone
Keyword(s):  
Mechanical Properties ◽  
Rolling Contact ◽  
Effect Of Temperature ◽  
Plastic Deformations ◽  
Rail Head ◽  
Class D ◽  
Shakedown Theory ◽  
Freight Car ◽  
Class C ◽  
Railroad Wheels

Plastic deformations alter the mechanical properties of many metals and alloys. Class C and Class D wheel steels such as are used in North American freight car service are particularly affected by plastic deformations occurring during rolling contact between the wheel tread and rail head. This investigation determines the effect plastic deformations have on the mechanical properties of Class C and D wheel steels and how those changes could relate to shakedown theory. The effect of temperature is also discussed.

Influence of shape of impactormade from high-strength steel on its fracture at high deformation rates

2021 ◽  
pp. 44-51
Author(s):  
P.A. Radchenko ◽  
◽  
S.P. Batuev ◽  
A.V. Radchenko ◽  
◽  
...  
Keyword(s):  
Finite Element Method ◽  
Fracture Criterion ◽  
Three Dimensional ◽  
High Strength ◽  
Head Part ◽  
The Finite Element Method ◽  
Plastic Deformations ◽  
High Deformation ◽  
Limit Value ◽  
Interaction Velocity

The fracture of high-strength impactor in interaction with a steel barrier is investigated. Three typesof head parts of the impactor are considered: flat, hemispherical and ogival. Normal and oblique interactions with velocities of 700 and 1000 m/s are investigated. Modeling is carried out by the finite element method in a three-dimensional formulation using the author's software EFES 2.0.The limit value of intensity of plastic deformations is used as a fracture criterion. The influence of the striker head part shape, interaction velocity, interaction angle on the fracture of the impactor and the barrier has been investigated. Conditions under which the striker ricochets were defined.

Effect of defect length on rolling contact fatigue crack propagation in high strength steel

2015 ◽  
Author(s):  
T. Makino ◽  
Y. Neishi ◽  
D. Shiozawa ◽  
Y. Neishi ◽  
D. Shiozawa ◽  
...  
Keyword(s):  
Crack Propagation ◽  
High Strength Steel ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
High Strength ◽  
Rolling Contact ◽  
Micro Ct ◽  
Middle Line ◽  
Micro Computed Tomography ◽  
Depth Direction

 The objective of the present paper is to clarify the effect of defect length in depth direction on rolling contact fatigue (RCF) crack propagation in high strength steel. RCF test and synchrotron radiation micro computed tomography (SR micro CT) imaging were conducted. In the case of the defect with the 15 ?m diameter, flaking life decreased with increasing defect length. In a comparison of the CT image and the SEM view, the shapes of defects and the locations of the horizontal cracks were almost the same respectively. The mechanism of RCF crack propagation was discussed by finite element (FE) analysis. Defects led to higher tensile residual stress than that without defects in the region where the defect exists. The shear stress range at 0.1 mm in depth on the middle line of the defect and the range of mode II stress intensity factor at the bottom of a vertical crack increased with increasing defect length.

Effect of Repeated Quenching on the Rotating Bending Strength of SAE52100 Bearing Steel

2012 ◽  
Vol 457-458 ◽  
pp. 1025-1031 ◽  
Author(s):  
Koshiro Mizobe ◽  
Edson Costa Santos ◽  
Takashi Honda ◽  
Hitonobu Koike ◽  
Katsuyuki Kida ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Bending Strength ◽  
High Strength ◽  
Bearing Steel ◽  
Rolling Contact ◽  
High Wear Resistance ◽  
High Carbon ◽  
Austenite Grain ◽  
High Fatigue ◽  
Rotating Bending

Martensitic high carbon high strength SAE 52100 bearing steel is one of the main alloys used for rolling contact applications where high wear resistance are required. Due to its high fatigue strength, SAE 52100 is recently being used not only for the production of bearings but also shafts. Refining of prior austenite grain through repeated quenching is a procedure that can be used to enhance the material’s strength. In this work, the microstructure of repeatedly quenched SAE 52100 steel and its fatigue strength under rotating bending were investigated. It was found that repeated furnace heating and quenching effectively refined the martensitic structure and increased the retained austenite content. Repeated quenching was found to improve the fatigue strength of SAE 52100.

Research on the Approach for the Assessment of Subsurface Rolling Contact Fatigue Damage

2013 ◽  
Vol 395-396 ◽  
pp. 845-851
Author(s):  
Xiao Feng Qin ◽  
Da Le Sun ◽  
Li Yang Xie
Keyword(s):  
Shear Stress ◽  
Friction Coefficient ◽  
Fatigue Damage ◽  
Stress Ratio ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Critical Stresses ◽  
Orthogonal Shear Stress

In this paper, the distribution of different critical stresses, which were used in previous correlation articles for the assessment of subsurface rolling contact fatigue damage, was analyzed. The rationality of orthogonal shear stress was selected as the key stress controlling the subsurface rolling contact fatigue damage was clarified. Base on the linear fatigue damage accumulative theory and the modification equation for the range of asymmetrical stress, the influence of friction on subsurface rolling contact fatigue damage was studied. The results show that the subsurface orthogonal shear stress is a completely symmetrical stress when the friction coefficient is zero, while it is an asymmetrical stress with considering the friction. The stress ratio of subsurface orthogonal shear stress and subsurface rolling contact fatigue damage is increased with the increasing of friction.

scholarly journals Numerical simulation and experimental comparison of flaw evolution on a bearing raceway: Case of thrust ball bearing

2018 ◽  
Vol 5 (4) ◽  
pp. 427-434 ◽  
Author(s):  
M.Y. Toumi ◽  
S. Murer ◽  
F. Bogard ◽  
F. Bolaers
Keyword(s):  
Structural Damage ◽  
Ball Bearing ◽  
Rolling Contact ◽  
Experimental Comparison ◽  
Ball Bearings ◽  
Damage State ◽  
Element Analysis ◽  
Rolling Surface ◽  
Experimental Apparatus ◽  
Good Agreement

Abstract Bearings are essential elements in the design of rotating machines. In an industrial context, bearing failure can have costly consequences. This paper presents a study of the rolling contact fatigue damage applied to thrust ball bearings. It consists in building a dynamic three-dimensional numerical model of the cyclic shift of a ball on an indented rolling surface, using finite element analysis (FEA). Assessment of the evolution in size of a surface spall as a function of loading cycles is also performed using FEM coupled with fatigue laws. Results are in good agreement with laboratory tests carried out under the same conditions using a fatigue test cell dedicated to ball bearings. This study may improve knowledge about estimating the lifetime of rolling components after onset of a spall using FEA and accounting for structural damage state. Highlights The experimental apparatus and damaged thrust ball bearing are described. We model a portion of the thrust ball bearing featuring a spherical indent. Numerical results in terms of stress field are compared to analytical results from the literature. A fatigue software is used to assess the evolution of spalling size. Good agreement is obtained between experimental test campaigns at different loads and FEA results.

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