Further Investigation of a Relation for Cumulative Fatigue Damage in Bending 640498

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


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.

Due to current capacity constraints, printed versions of our publications - including standards, technical papers, EDGE Reports, scholarly journal articles, books, and paint chips - may experience shipping delays of up to four to six weeks. We apologize for any inconvenience.
We also recommend:

Dimensional Variation in Long Runout Length Direct Extruded 6000 Series Aluminum Alloy


View Details


Fatigue Life Prediction for Variable Amplitude Strain Histories


View Details


Bending Fatigue Life Analysis of Carburized Components Using Strain Life and Fracture Mechanics Approaches


View Details