Surface displacement mapping of piezoelectric multilayer actuators

At NPL, methods of measurement have been developed to accurately measure the piezoelectric displacement of a variety of piezoceramics. In this work package the focus is not so much on accuracy and traceablity but on developing techniques for the point-to-point scanning of actuators. This means that the piezoelectric displacement is measured on a small region of the sample and then either the sample or the measuring probe is scanned in order to build up a map of displacement behaviour. Two optical techniques have been explored in this paper: 1. Laser Doppler Vibrometer and 2. Laser Triangulation. Both measurement methods have successfully revealed sub-surface features within specially fabricated mulitlayer-actuators.