Spherical indentation on a prestressed elastic coating/substrate system

While there have been many studies on the indentation test of thin film/substrate systems, the primary goal has been determining the film properties. However, there was very little effort to probe the properties of both the film and the substrate (the latter may be as important as the film properties). Moreover, a prestress usually exists in the film, typically resulted from mismatched deformation or material properties. In this study, we establish a spherical indentation framework to examine the material properties of both the film and substrate as well as determining the film prestress. An indentation test is performed at two prescribed depths, and functional forms are established between indentation parameters and material variables. An effective reverse analysis algorithm is established to deduce the desired material properties. The potential error sensitivity is also examined in a systematic way. The study on prestressed film/substrate systems has many potential applications in engineering. © Springer Nature Switzerland AG 2019. All rights reserved.