52:42
Force and displacement measurements obtained from instrumented indentation experiments are interpreted using elastic contact models, even when the contact causes plastic deformation. Elastic contact models specify the ideal relationship between force, displacement, and elastic properties. Such models are explained in this presentation. Ian Sneddon’s elastic contact model is given special attention due to its generality, and the models of Hertz and Love are shown to be special cases of Sneddon’s model. Many examples are provided which show how to apply Sneddon’s model to specific geometries ...
53:30
In 1992, Warren Oliver and George Pharr published an article that revolutionized hardness testing. The genius of Oliver and Pharr was that they devised a way to know the size of a hardness indentation without imaging it. This development disrupted Vickers and Knoop microhardness testing, which required direct measurement of the lengths of the indentation diagonals. Not having to image the indentation paved the way for fully automated hardness testing. Not only was automated testing independent of human bias, it was also much faster, because multiple tests on multiple samples could be prescr...
