The recent development of actuators based on giant magnetostrictive materials in for instance hydroacoustic transducers has caused an increase in output forces from the drive elements used. The high stress levels make testing of the actuators with well defined mechanical loads difficult. The need for standards and improved evaluation methods has therefore become evident.

Based on experiences from earlier test facilities a new set-up has been designed with the intention to obtain

- higher resonance frequency

- facilitated assembly of test objects

- increased operating forces

- flexible choice of mechanical loads

- computer controlled measurement procedure

- controllable environmental conditions, for instance temperature.

In order to achieve the specifications, the test rig involves hydraulics for prestressing and clamping of the test object and the mechanical load. A method of mechanically disconnecting the prestress device from the fixture gives lower mass to stiffness ratio in the fixture and therefore a better high frequency performance.

The presented test rig is considered to have the prerequisites of serving as a platform for future evaluation and standardization of actuators.