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High-Power, Low-Frequency, Textured PMN-PT Underwater Projector


TECHNOLOGY AREA(S): Materials, Electronics, Battlespace 

OBJECTIVE: Develop, fabricate, test, and demonstrate a low-frequency, high-powered, underwater acoustic transducer that employs the enhanced properties of PMN-PT (lead magnesium niobate - lead titanate) textured ceramic and allows for integration into an air-deployable sensor. 

DESCRIPTION: Coherent low-frequency underwater acoustic transducer designs are typically of the flextensional or flexural type and are optimized to operate under small-volume constraints. These designs commonly employ piezoelectric ceramic lead zirconate titanate (PZT). In these devices, the power output is field-limited and not stress-limited. Application of these transducers toward air-deployable expendable sensors - sonobuoys - poses unique limitations on size, power, and cost. The recent development of ferroelectric PMN-PT textured ceramics, which have electromechanical properties between those of conventional PZT and relaxor PMN-PT crystals, has shown the promise of increased power output, relative to Navy Type III piezoceramic, of at least 10dB without significant cost increase. This increase in performance allows for transducer designs that are better suited to operate at high stress- and field-limits while maintaining a compact form factor. These improvements in source level and bandwidth would yield a considerable performance increase in terms of target detections and extended detection ranges. The end use of these projectors is for an array that is capable of generating high acoustic power while exhibiting broad bandwidth that could be integrated into an A-sized air-deployable sensor. A notional design would be a transducer that is approximately 5 inches in diameter, can achieve source levels that exceed those achievable by conventional PZT ceramics, and maintain as broad an operational bandwidth as possible at the 0.5kHz to 2kHz range. Variations on established flextensional and/or flexural type transducers should be considered; however, final design considerations are not limited to these technologies. Work produced in Phase II may become classified. Note: The prospective contractor(s) must be U.S. Owned and Operated with no Foreign Influence as defined by DOD 5220.22-M, National Industrial Security Program Operating Manual, unless acceptable mitigating procedures can and have been implemented and approved by the Defense Security Service (DSS). The selected contractor and/or subcontractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances, in order to perform on advanced phases of this contract as set forth by DSS and NAVAIR in order to gain access to classified information pertaining to the national defense of the United States and its allies; this will be an inherent requirement. The selected company will be required to safeguard classified material IAW DoD 5220.22-M during the advance phases of this contract. 

PHASE I: Design and demonstrate the feasibility of a device that can meet the notional need and be optimized to exploit the properties of PMN-PT textured piezoceramic. Undertake at least two paper design variations to assess the strengths of the approach. Select a single prototype design to pursue/develop in Phase II; analyze all aspects of the design; and perform a cost analysis for production. 

PHASE II: Complete the high-powered, low-frequency underwater projector design selected in Phase I and fabricate two prototypes. Undertake a complete electroacoustic analysis of the prototypes including high-power in-water testing, continuous duty high-power operation, and a design review package. Verify the computer model of the transducer design with measured data to assess the viability of the model and its ability to modify performance parameters while maintaining tractability. If necessary, make adjustments to the design, fabricate revised prototypes, and repeat the testing and model verification regime. Compare the final test and model results with the notional performance goals. It is probable that the work under this effort will be classified under Phase II (see Description section for details). 

PHASE III: Continue to extensively test the prototype fabricated in Phase II and test for severe environmental conditions of depth, power output, duty cycle, and sensor deployment. Fabricate, assemble, and test an array to assess performance. Working with a Navy POC, match the achieved performance with current Navy needs and transition this technology for its intended purpose. The development of this technology will have application to the oceanographic community and the oil exploration industry. 


1: Stephen F. Poterala, Susan Trolier-McKinstry, Richard J. Meyer Jr., and Gary L. Messing. "Processing, texture quality, and piezoelectric properties of <001>C textured (1-x)Pb(Mg1/3Nb2/3)TiO3 - xPbTiO3 ceramics." Applied Physics Letters Vol. 110, Issue 1, 0145105 (2011),

2:  Poterala, Stephen F., Meyer, Richard J., and Messing, Gary L. "Fabrication and properties of radially <001>C textured PMN-PT cylinders for transducer applications." Journal of Applied Physics, Vol. 112, Issue 1, 014105 (2012).

3:  Holler, Roger A., Horbach, Arthur W. and McEachern, James F. The Ears of Air ASW: A History of U.S. Navy Sonobuoys. Navmar Applied Sciences Corporation, 2008. ISBN 978-0-615-20113-9, 2008.

4:  Introduction to Theory and Design of Sonar Transducers. ISBN 978-0932146229, 1989

KEYWORDS: Transducer; Sonobuoys; Textured Ceramics; Underwater Acoustics; Source Level; Bandwidth 


Ivan Lopez-Alvarado 

(301) 757-3617 

Mary Eileen Farrell 

(301) 342-2114 

Benjamin Harrison 

(301) 342-2028 

Lauren Sturdy 

(301) 342-2090 

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