Further Investigation of a Relation for Cumulative Fatigue Damage in Bending

640498

01/01/1964

Event
SAE World Congress & Exhibition
Authors Abstract
Content
The fatigue behavior of several steels, AISI 4130, E52100, and 304 ELC stainless, as well as that of a nonferrous alloy, 5456-H311, was investigated in rotating bending fatigue after these materials were subjected to a prestress for different cyclic histories. The data obtained corroborated the hypothesis proposed by the authors that lines representing the S - log N relation of a material prestressed in varying amounts will intersect the S - log N line of the original material near a common point.
A correlation was found between the stress at this intersection point and the ultimate tensile strength. Thus, the only requirements for establishing the fatigue behavior of a prestressed material in the range of stresses where the S -log N line is inclined are the S - log N line of the original material and the ultimate tensile strength.
The importance of determining the new endurance limit of a material after prestressing was shown analytically. The omission from cycle ratio summations of cyclic histories applied below the original, but above the new endurance limit of a material, was shown for an illustrative example to result in a cycle ratio summation less than unity, which leads to unconservative estimates of fatigue life. Cyclic histories so applied can produce damage and must be taken into account. A new hypothesis based upon actual fatigue behavior and incorporating a cycle-ratio - modified-stress-ratio factor is suggested, which holds promise for more accurately predicting the new endurance limit than most existing methods. Extensive additional tests are required to verify this concept
Meta TagsDetails
DOI
https://doi.org/10.4271/640498
Pages
15
Citation
Manson, S., Nachtigall, A., Ensign, C., and Freche, J., "Further Investigation of a Relation for Cumulative Fatigue Damage in Bending," SAE Technical Paper 640498, 1964, https://doi.org/10.4271/640498.
Additional Details
Publisher
Published
Jan 1, 1964
Product Code
640498
Content Type
Technical Paper
Language
English