"CERAMIC—METAL COMPOSITE ACTUATOR"

By R.E. Newnham, et al.

PSU Inv. Disc. No. 1050

Licensing Contact: Matthew D. Smith

Issued U.S. Patent No. 5,276,657

A group of researchers at Penn State's Material Research Laboratory have developed a new type of actuator which has large effective d33 coefficients exceeding 3000 pC/N (30 A/V) which are obtained with existing composite actuators.

The above-referenced invention consists of piezoelectric or electrostrictive ceramic material and metal. The radial motion of the piezoelectric ceramic is converted into a flextensional motion in the metal. As a result, a large displacement is obtained in the direction perpendicular to the ceramic material. In this invention, the axial displacement comes from two sources, the longitudinal displacement of the ceramic itself often described using d33 coefficient; the other is the flextensional motion of the metal arising from the radial motion of the ceramic stems from ceramics d32 and d31 coefficients. The two contributions add together to give unusually large displacements which can be described by an effective d33 coefficient.