Indentation fatigue mechanics

Instrumented indentation has been widely used in the determination of mechanical properties of materials due to its fast, simple, precise, and nondestructive merits over the past few years. In this chapter, we will present an emerging indentation technique, referred to as indentation fatigue, where a fatigue load is applied on a sample via a flat punch indenter, and establish the framework of mechanics of indentation fatigue to extract fatigue properties of materials. Through extensive experimental, theoretical, and computational investigations, we demonstrate a similarity between the indentation fatigue depth propagation and the fatigue crack growth, and propose an indentation fatigue depth propagation law and indentation fatigue strength law to describe indentation fatigue-induced deformation and failure of materials, respectively. This study provides an alternative approach for determining fatigue properties, as well as for studying the fatigue mechanisms of materials, especially for materials that are not available or feasible for conventional fatigue tests.