The purpose of this paper is to outline a method for evaluating the low cycle fatigue resistance of a metal from the mechanics of materials viewpoint. This includes a discussion of the fatigue properties and the effect of repeated plastic straining on the mechanical properties of metals. The cyclic stress-strain curve is defined as the locus of tips of several stable hysteresis loops obtained at different cyclic strain ranges. An expression is presented for mathematically representing the locus of their tips, and a number of experimental methods are discussed for determining the stable cyclic stress-strain properties.

Experimental techniques for low cycle fatigue testing and methods of interpreting results are presented. The equations which relate the elastic and plastic components of cyclic strain amplitude to fatigue life are developed. A means of approximating the strain-life curve using these relations is presented.