Goodman relation

In materials science and fatigue, the Goodman relation is an equation used to quantify the interaction of mean and alternating stresses on the fatigue life of a material. In materials science and fatigue, the Goodman relation is an equation used to quantify the interaction of mean and alternating stresses on the fatigue life of a material. A Goodman diagram,sometimes called a Haigh diagramor a Haigh-Soderberg diagram,is a graph of (linear) mean stress vs. (linear) alternating stress, showing when the material fails at some given number of cycles. A scatterplot of experimental data shown on such a plot can often be approximated by a parabola known as the Gerber line,which can in turn be (conservatively) approximated by a straight line called the Goodman line.