ABSTRACT
Chapter 13 gave us some idea about how the normal load controls damage evolution and the subsequent interactions during dynamic contact in an SLS glass. When a vehicle runs across the road, the road gets damaged due to the dynamic contact between the wheel and the road. Our common understanding is that the type of the vehicle, i.e., if it is a lightweight private car or a heavyweight truck, determines the kind of damage inflicted on the road. This picture means that the effective applied load on the wheel, i.e., the weight of the vehicle, is an important parameter in the creation of damage. The previous chapter gave us a scenario of damage in SLS glass under various contact loads that matches with this picture. But now imagine this story. You are running behind your friend toward a finish line consisting of a fixed sharp glass plate with sharp edges, and both of you just mildly touch this winning post as you pass by, say within few seconds of each other. Will either of you suffer any physical damage? The answer is no. Now imagine that both of you run superfast; you run much faster than your friend and, failing to control, bump into the fixed sharp glass plate at the finish line. Maybe your friend does almost the same thing but bumps into the same fixed sharp glass plate at a slightly slower speed than yours. Common sense tells us that you are the person who gets hurt the most; your friend also gets hurt, but a little less than you. In other words, the speed of contact can and really does matter. Therefore, especially in the case of dynamic contact-induced damage initiation and growth in a brittle material like SLS glass, we need to understand to what extent the speed of contact matters.
