3. Pendulum hardness tests

Various authors have pointed out that defining hardness by measuring the indenter's footprint, either after rebound or after load removal, can lead to confusion.

For example, the low-load hardness test on rubber would give infinite hardness, since the indentation is zero. In this case, the deformation produced is purely elastic.

The advantage of the pendulum method is that it enables this type of hardness to be defined, thanks to a measurement made during the action of the ball. It can also be used to define the overall hardness (elastic and plastic) if the applied load exceeds the elastic limit.

This method is rarely used, and is mentioned here only to suggest possible applications. It consists in determining the duration of oscillation of a pendulum resting on the surface to be studied by means of a ball, the shorter...