High-displacement spiral piezoelectric actuators

A high-displacement piezoelectric actuator, employing spiral geometry of a curved piezoelectric strip is described. The monolithic actuators are fabri cated using a layered manufacturing technique, fused deposition of ceramics , which is capable of prototyping electroceramic components with complex sh apes. The spiral actuators (2-3 cm in diameter) consisted of 4-5 turns of a lead zirconate titanate ceramic strip with an effective length up to 28 cm . The width was varied from 0.9 to 1.75 mm with a height of 3 mm. When driv en by the electric field applied across the width of the spiral wall, the t ip of the actuator was found to displace in both radial and tangential dire ctions. The tangential displacement of the tip was about 210 mu m under the field of 5 kV/cm. Both the displacement and resonant frequency of the spir als could be tailored by changing the effective length and wall width. The blocking force of the actuator in tangential direction was about 1 N under the field of 5 kV/cm. These properties are advantageous for high-displaceme nt low-force applications where bimorph or monomorph actuators are currentl y employed. (C) 1999 American Institute of Physics. [S0003-6951(99)05442-X] .