High resolution measurement of dynamic (nano) indentation impact energy: a step towards the determination of indentation fracture resistance

A Micro Materials (UK) NanoTest has been modified for fast data acquisition at up to 200 kHz to enable high-resolution (sub-pJ) impact energy measurement. Displacement versus time data were acquired at 20 kHz in 3-s bursts to capture the acceleration, impact and rebounding of the pendulum-mounted indenter. The data acquired were analysed to provide measurements of position, velocity, acceleration, impact distance, impact depth (elastic and plastic) potential and kinetic energy throughout the impact cycle and provided high-resolution information throughout the impact event itself, which lasted only ∼ 10 ms. The ability of the system to detect fracture events and measure energies associated with these events is investigated. The effect of impact energy and indenter geometry is demonstrated and it is shown that the system is able to detect damage events and measure the difference in the energy absorbed in an impact when damage occurs.