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User Toolkit for Reducing Cost and Time in the Design of SONAR Systems Using Relaxor Piezoelectric Single Crystals
Navy SBIR 2008.1 - Topic N08-063 ONR - Mrs. Tracy Frost - [email protected] Opens: December 10, 2007 - Closes: January 9, 2008 N08-063 TITLE: User Toolkit for Reducing Cost and Time in the Design of SONAR Systems Using Relaxor Piezoelectric Single Crystals TECHNOLOGY AREAS: Materials/Processes, Sensors, Weapons ACQUISITION PROGRAM: PMS 415 Undersea Defensive Warfare Systems OBJECTIVE: Provide a transducer design methodology to reduce the cost and time for inserting into Navy systems innovative transducers based on relaxor piezoelectric single crystals. DESCRIPTION: Near the onset of 1997 came the discovery that single crystals of certain relaxor ferroelectric (lead magnesium niobate � lead titanate, and lead zinc niobate � lead titanate) materials exhibit extraordinary piezoelectric properties, namely, strains exceeding 1%, and electromechanical coupling exceeding 90% (compared to 0.1% and 70-75 %, respectively, in state-of-the-art piezoceramics)(References 1 and 2). Concerted efforts to grow these materials in a variety of forms now yield materials in quantities, and at a price, suitable for devices. Three domestic manufacturing firms now supply these materials as well as several more overseas; initial devices have been developed and commercialized (References 3, 4 and 5). This topic aims to reduce the cost and time needed to exploit these enhanced electromechanical properties in practical Navy devices. In broad brush, the piezocrystals� impact is clear. For example in acoustic transducers, the high coupling leads to higher bandwidth (doubled to two octaves or more), while the high strain leads to higher source levels (more than an order of magnitude increase); actuators employing these materials are more efficient and compact; and sensors are smaller and more sensitive. Yet a system designer wanting to use the relaxor piezocrystals needs a grasp of the specific gains and trade-offs amongst them; this is usually achieved by looking at transducers already "on the shelf." Sadly, the relaxor piezocrystal transducer "shelf" is, at this time, sparsely populated. This topic will populate that shelf by providing a "user toolkit" (reference 6) that will allow the system designer to explore options and determine the benefits with reasonable fidelity. This exploration allows the system designer to home in on preliminary system concept that effectively exploits the relaxor piezocrystals. This "toolkit" is likely to consist of separate modules for each class of transducers (Reference 7) that will allow the system designer to vary a number of device parameters and obtain acoustic performance (bandwidth, source level, sensitivity, etc.) and other system characteristics (size, weight, electrical requirements, etc.). This "trial and error" exploration will reduce time and cost in arriving at a good first cut. Next follows a fully detailed, professionally executed transducer design and the conventional build-test-modify design cycle. PHASE I: Devise a user toolkit module that allows a system designer to explore, with reasonable fidelity, a single class of transducer. Demonstrate its utility with a concrete design example---preferably one chosen from a real Navy SONAR design problem. No hardware is required. PHASE II: Expand the user toolkit by constructing additional modules to encompass multiple classic piezoelectric transducer designs. Complete at least one real design problem from concept development through the end of one design-build-test-modify cycle. Only transducer hardware, not a full system, need be built. PHASE III: Expand the span of design modules to encompass the full range of SONAR transducers. Cement linkages with materials suppliers, transducer manufacturers and system designers by active participation in Navy SONAR systems development. PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Once established, this design methodology can be extended readily to include modules suitable for a broad range of piezoelectric devices, in the defense sector from Navy SONAR, through Army rotorblade control, to Air Force airfoil shape control�all have analogs in the civilian sector. Other applications will have their primary impact in the civilian arena, including medical ultrasonics, active machine tool control, and vibration suppression in HVAC systems. REFERENCES: 2. S.-E Park and T.R. Shrout, "Characteristics of Relaxor-Based Piezoelectric Single Crystals for Ultrasonic Transducers," IEEE Trans. On Ultrasonic Ferroelectrics and Frequency Control, Vol. 44, No. 5, 1140-1147 (1997). 3. J. M. Powers, M. B. Moffett, and F. Nussbaum, "Single Crystal Naval Transducer Development," Proceedings of the IEEE International Symposium on the Applications of Ferroelectrics, 351-354 (2000). 4. Jie Chen and Rajesh Panda, "Review: Commercialization of Piezoelectric Single Crystals for Medical Imaging Applications," Proceedings of the 2005 IEEE Ultrasonics Symposium, 235-240 (2005). 5. Harold C. Robinson, James M. Powers, and Mark B. Moffett, "Development of broadband, high power single crystal transducers," Proceedings of the 2006 SPIE International Symposium on Smart Structures and Materials, in press (2006). 6. Eric von Hippel, "Application: Toolkits for User Innovation and Custom Design," Chapter 11 pp. 147-164 in "Democratizing Innovation," The MIT Press, 2006, available on the website: http://web.mit.edu/evhippel/www/ 7. Charles H. Sherman and John L. Butler, "Transducers and Arrays for Underwater Sound," Springer, 2007. KEYWORDS: Electromechanical Sensors and Actuators; SONAR Transducers; SONAR System Design; Piezoelectrics; Lead Magnesium Niobate�Lead Titanate; Lead Zinc Niobate�Lead Titanate TPOC: Teresa McMullen
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