Development of novel piezoelectric ceramics and composites for sensors and actuators by solid freeform fabrication

Novel piezoelectric ceramic, and ceramic/polymer composite structures were fabricated by solid freeform fabrication (SFF) for sensor and actuator applications. SFF techniques including: Fused Deposition of Ceramics (FDC) and Sanders Prototyping (SP) were utilized to fabricate a variety of complex structures directly from a computer aided design (CAD) file. Many novel and complex composite structures including volume fraction gradients (VFG), staggered rods, radial and curved composites, and actuator designs such as tubes, spirals and telescopings were made using the flexibility provided by the above processes. Radial composites with various connectivities in the radial direction were made for towed array applications. The FDC process was also used to fabricate curved composites with desired radii of curvatures for focusing high intensity ultrasound beams at different points along the axial direction. VFGs were incorporated into some of these designs, with the ceramic content decreasing from the center towards the edges. Many new designs are also being used to manufacture high authority actuators utilizing the FDC technique. The design, fabrication and electromechanical properties of these sensor and actuator structures are discussed in this paper.