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Materials and Device Modeling to Reduce Cost and Time to Exploit Relaxor Piezoelectric Single Crystals in Navy SONAR Transducers
Navy SBIR 2008.1 - Topic N08-061 ONR - Mrs. Tracy Frost - [email protected] Opens: December 10, 2007 - Closes: January 9, 2008 N08-061 TITLE: Materials and Device Modeling to Reduce Cost and Time to Exploit Relaxor Piezoelectric Single Crystals in Navy SONAR Transducers 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. To effectively exploit these "break-through" materials, the transducer design engineer requires a substantial body of materials properties (Reference 6) (dielectric, elastic and piezoelectric tensors), both linear and non-linear responses along with their loss tangents, over a broad range of operating conditions (temperature, electric field and mechanical stress). Moreover, the device modeling must be validated by making exemplar devices and comparing the predictions with detailed measurements over a substantial range of naval operating conditions. A diverse team�materials producers and property measurers, plus device designers, builders and evaluators�must be assembled to carry out this endeavor drawn from industry, academe and government labs (which will be funded from non-SBIR sources beyond the proposed SBIR effort). While a substantial undertaking, the payback will be even more substantial in reducing the cost and time needed to take full advantage of the piezocrystal technology in Navy SONAR systems. This SBIR effort will yield dramatic reductions in the number of design-built-test iterations needed to make an optimal transducer in the short term; moreover, further cost/time savings will emerge in the long term as fielded systems are repaired and upgraded. PHASE I: Measure selected materials properties (supplementing the published literature) sufficient to produce specific performance predictions for at least one candidate Navy SONAR transducer; build and evaluate an exemplar device. It would be a big plus if the exemplar represents a real Navy SONAR problem. PHASE II: Expand the properties data base to encompass enough properties to model a broad selection of transducer designs (Reference 6); build and evaluate, over a large range of operating conditions, two or more fundamentally different classes of transducer. It would be a big plus if these demonstration efforts were embedded within a real Navy SONAR development program. PHASE III: Expand the property data base to include new materials that emerge as the materials community produces compositionally modified piezocrystals to tune specific materials properties to specific device needs. Increase the span of device design 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 data base and design methodology can be extended readily to 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. 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: Wallace Smith
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