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Hertzian fatigue

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Series: ASM Handbook
Volume: 11A
Publisher: ASM International
Published: 30 August 2021
DOI: 10.31399/asm.hb.v11A.a0006820
EISBN: 978-1-62708-329-4
... lubrication, the measurement of the backlash, and the necessary factors for starting the failure analysis. Next, the article explains various gear failure causes, including wear, scuffing, Hertzian fatigue, cracking, fracture, and bending fatigue, and finally presents examples of gear and reducer failure...
Series: ASM Handbook
Volume: 18
Publisher: ASM International
Published: 31 December 2017
DOI: 10.31399/asm.hb.v18.a0006354
EISBN: 978-1-62708-192-4
... discharge), scuffing, and Hertzian fatigue (including macropitting and micropitting). Details for obtaining high lubricant specific film thickness are presented. The article describes the selection criteria for lubricants, such as oil, grease, adhesive open gear lubricant, and solid lubricants. It discusses...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002401
EISBN: 978-1-62708-193-1
... Abstract The mechanism of contact fatigue can be understood in terms of several sources of stress concentration, or stress raisers, within the macroscopic Hertzian stress field. This article focuses primarily on rolling contact fatigue of hardened bearing steels. It discusses Hertzian shear...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006792
EISBN: 978-1-62708-295-2
.... A brief discussion on coatings to improve surface-initiated fatigue and wear is included, due to the similarity to RCF and the increasing criticality of this failure mode. The article presents a working knowledge of Hertzian contact theory, describes the life prediction of rolling-element bearings...
Image
Published: 30 August 2021
Fig. 62 Double-row angular-contact ball bearing that cracked due to insufficient/improper axial support. The fracture crack originated from the middle of the raceway beyond the loaded zone. This shows the interaction of volumic and Hertzian stresses, which led to breakage of the raceway More
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003564
EISBN: 978-1-62708-180-1
... of the ring and cone fracture is provided by the Hertz theory of elastic contact. Traditionally, Hertzian cone cracks have been most widely studied in flat, silicate glass plate, using spheres of hard steel or tungsten carbide. Extension to ceramics is becoming more prevalent, and the theory of Hertzian...
Book Chapter

Series: ASM Handbook
Volume: 18
Publisher: ASM International
Published: 31 December 2017
DOI: 10.31399/asm.hb.v18.a0006358
EISBN: 978-1-62708-192-4
... of the gear unit—that is, the pitch diameter, gear ratio, and the face width—often must involve consideration of the Hertzian conditions necessary to avoid pitting failure of the gear face within the design life. Several types of pitting are recognized with regard to gear surface fatigue failures...
Series: ASM Handbook
Volume: 11A
Publisher: ASM International
Published: 30 August 2021
DOI: 10.31399/asm.hb.v11A.a0006834
EISBN: 978-1-62708-329-4
...). The goal is to obtain a core-hardness range of 25 to 45 HRC and surface-hardness values below the minimum 58 HRC. The core ductility improves in such a way that the volumic fatigue strength and the case hardness allow the part to overtake high Hertzian contact stresses and minimize wear. Typical...
Book Chapter

Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003099
EISBN: 978-1-62708-199-3
... sufficient hardness on and below the surface to resist abrasive/adhesive wear and to minimize contact fatigue in the whole region of the surface and below so that the material strength at each point is higher than the surface or subsurface shear stresses that occur from a loaded Hertzian surface stress...
Book Chapter

Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003544
EISBN: 978-1-62708-180-1
... Abstract This article describes three design-life methods or philosophies of fatigue, namely, infinite-life, finite-life, and damage tolerant. It outlines the three stages in the process of fatigue fracture: the initial fatigue damage leading to crack initiation, progressive cyclic growth...
Series: ASM Handbook Archive
Volume: 11
Publisher: ASM International
Published: 01 January 2002
DOI: 10.31399/asm.hb.v11.a0003563
EISBN: 978-1-62708-180-1
... bearing) or nonconforming (e.g., contact between the inner race and roller in a rolling-element roller bearing). The alternating stress field responsible for RCF failure can generally be idealized from Hertzian contact conditions in conventional metallic and ceramic materials (e.g., bearing steel and Si 3...
Series: ASM Handbook
Volume: 18
Publisher: ASM International
Published: 31 December 2017
DOI: 10.31399/asm.hb.v18.a0006399
EISBN: 978-1-62708-192-4
... counterformal contacts. The frictionless assumption of Hertzian theory is often relaxed, and a coefficient of friction is used to estimate friction. This approach is very empirical and should be avoided. Later, appropriate methods are outlined for calculating friction. Contact Fatigue With calculated...
Series: ASM Handbook
Volume: 18
Publisher: ASM International
Published: 31 December 2017
DOI: 10.31399/asm.hb.v18.a0006403
EISBN: 978-1-62708-192-4
... tribological action on a component (e.g., piston ring/cylinder liner; bearing shell/shaft). The contact-area-to-wear-track ratio is an important factor in developing suitable methods for testing. Fig. 4 Basic contact conditions for (a) conformal and (b) counterformal contact, with Hertzian contact...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006779
EISBN: 978-1-62708-295-2
... Abstract Fatigue failures may occur in components subjected to fluctuating (time-dependent) loading as a result of progressive localized permanent damage described by the stages of crack initiation, cyclic crack propagation, and subsequent final fracture after a given number of load...
Series: ASM Handbook
Volume: 8
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.hb.v08.a0003316
EISBN: 978-1-62708-176-4
... surfaces is defined by the normal force divided by the nominal area of contact. Subsurface stress distributions can be computed using Hertzian calculations and the macroscopic contact geometry. The normal stress is also influenced by geometric stress concentrations. The real area of contact is limited...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002372
EISBN: 978-1-62708-193-1
.... For Hertzian stresses of convex contacts, this depth is on the order of the half-width of the contact area. Beyond this depth, mode I crack propagation analysis can be used to predict the growth rate under the bulk stress state. Fig. 4 Example of fretting fatigue crack viewed in cross section. Courtesy...
Series: ASM Handbook
Volume: 19
Publisher: ASM International
Published: 01 January 1996
DOI: 10.31399/asm.hb.v19.a0002416
EISBN: 978-1-62708-193-1
... is the flexural stiffness of the plate for a quasistatically applied impact force, and E 2 is the modulus of the plate in the thickness direction. The first term on the right-hand side of Eq 2 accounts for flexural displacements, and the second term accounts for Hertzian indentation. For thin plates...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006789
EISBN: 978-1-62708-295-2
... fatigue is a typical fatigue failure induced by the cyclic application of contact stresses, quite often in lubricated conditions. In general, it involves nonconformal contacts, that is, line or point contacts, which are characterized by quite large elastic Hertzian stresses. Due to the repeated contact...
Series: ASM Handbook
Volume: 8
Publisher: ASM International
Published: 01 January 2000
DOI: 10.31399/asm.hb.v08.a0009224
EISBN: 978-1-62708-176-4
..., materials with high values of Young's Modulus of Elasticity/uniaxial flow stress (E/Y) (metals) appear to develop a Hertzian stress distribution over the contact. In contrast, materials with low values of E/Y (glasses and polymers) develop a uniform distribution of stress. cone angle elasticity...
Series: ASM Handbook
Volume: 18
Publisher: ASM International
Published: 31 December 2017
DOI: 10.31399/asm.hb.v18.a0006393
EISBN: 978-1-62708-192-4
... within the stress field exceeds the local yield strength. Surface origin Edge stress: Misalignment, overload, improper profile, and so on can result in a non-Hertzian contact stress profile. Concentrated stress at the edge of contact can accelerate crack initiation. Asperity fatigue...