<title>Characterization of different types of high-performance THUNDER actuators</title>

THUNDER technology introduces a versatile new family of rugged, robust, reliable piezoelectric actuators and sensors. Because of their pre-stressed composite structure, these powerful yet lightweight devices exhibit unprecedented performance in a durable, solid state package. Both sensors and actuators can be manufactured in a variety of adaptable geometries - squares, rectangles and disks - from several millimeters to many centimeters in size. Wide bandwidth performance can be achieved and maintained even in harsh chemical and temperature environments. Based on an invention patented by NASA, THUNDER is an emerging, enabling technology that holds the promise of significant advancements in numerous 'smart' applications. Development of these applications for smart materials and structures requires extensive characterization of a variety of THUNDER devices in a range of configurations. This comprehensive characterization effort is especially challenging because of the extraordinary flexibility and range of motion demonstrated by THUNDER devices, even under significant load. This paper will discuss important new work in the ongoing program of THUNDER device characterization. The program includes not only development of the characterization process, but also design and manufacture of the test and measurement equipment necessary to conduct meaningful and reliable testing on these unique, high performance devices. Results will be presented on characterization of two configurations of THUNDER devices, including a circular and a rectangular model of different sizes constructed of varying materials. Data will be offered for a number of key performance characteristics, including displacement, block force, plus displacement vs. voltage and displacement vs. force.