1974-02-01

Yield Criteria for Predicting the Strength of Metals 740797

Under certain conditions, metals and other solids deform plastically. There are two conditions which promote plastic deformation: the condition of stress and the mechanism which determines how that deformation takes place. The critical condition of stress which produces yielding is due to the net effect of the combination of stresses acting at a point. A mathematical theory which predicts the critical condition of stress for which plastic flow occurs is a yield criterion.
A new yield criterion is introduced. It is hyperbolic in form so it is significantly different from the criteria developed by Rankine, Tresca, Saint-Venant, or von Mises. But like these criteria, the new yield condition is also limited to a biaxial stress condition.
The new yield criterion, because of its form, serves as an instructive model for the development of an analytical equation of equivalent form. As a result, the new yield criterion can be interpreted as an energy equation which includes a mechanism related to how metals flow plastically. This mechanism can be related to small angle (gonio) distortions which develop in materials according to a pattern or form (morphous) that is either fixed or controlled by the basic structure of the material and the condition of stress. As a result, this new criterion is identified as a goniomorphous yield criterion.
The analytical equation is used as a pattern for two additional yield criteria. These new criteria predict yield for a three-dimensional condition of stress for two different deformation patterns.

SAE MOBILUS

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

Access SAE MOBILUS »

Members save up to 16% 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.
We also recommend:
TECHNICAL PAPER

Power Quality Analysis Framework for AC and DC Electrical Systems

2014-01-2209

View Details

TECHNICAL PAPER

Late Developments in Airplane Stress-Analysis Methods and Their Effect on Airplane Structures

320011

View Details

TECHNICAL PAPER

Photoelastic Stress Patterns: An Analytical Method for Producing Facsimilies of Experimental Results

730694

View Details

X