Interfacial elastic J  integral for indentation test

Abstract

Recently, the indentation test has drawn attention as a new method for evaluating the interfacial fracture toughness, since its application enables the in-situ measurement using a Vickers hardness tester. An empirical formula for the stress intensity factor or J integral has been utilized to evaluate the interfacial fracture toughness from the indentation test. However, the method's applicability was restricted to a certain range of material combinations, which motivated this study. The object of this study is to find a general form of the interfacial J integral that can be applied to a wide range of material combinations. To accomplish this, the J integral was formulated by solving the interfacial fracture problem of the dissimilar material plate-shaped model with semi-elliptical crack located at the interface that is subjected to an indentation load modeled by point loads. Arbitrary material combinations and crack geometries were considered here. The validity of the J integral introduced here was confirmed by comparing to the numerical J integral evaluated by three-dimensional finite element analysis.

Keywords

• dissimilar material
• interfacial fracture toughness
• indentation test
• interfacial elastic j integral
• stress intensity factor
• finite element analysis