TECHNOLOGY AREAS: Sensors, Electronics, Battlespace

ACQUISITION PROGRAM: PEO IWS5

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 3.5.b.(7) of the solicitation.

OBJECTIVE: The objective is to design and develop underwater acoustic transducers that are specifically designed for high power continuous duty operation.

DESCRIPTION: Traditionally, high power, broadband underwater acoustic projectors are designed for operation with a duty cycle in the vicinity of 10%. There is an interest to excite sonar system arrays at a continuous duty or 100% operation. This continuous operation will impose thermal issues since there is no time between pulses for the transducer to dissipate heat generated during the pulse. There are also mechanical design issues caused by a continuous excitation state especially when the transducer is being driven at high power. There is a need for underwater sonar projectors that are designed for continuous operation. The frequency band of interest spans from below one kilohertz to up to 100 kilohertz. High power can be identified as a transducer that radiates acoustic power much greater that 10 watts per square centimeter.

PHASE I:
* Identify a transducer with a notional resonance frequency of, let's say, 1 kHz or 10 kHz and design the transduction mechanism to be capable of high power operation at a continuous output mode of operation.
* Develop an analytical or numerical model of the candidate transducer.
* Identify the components/mechanisms that will be stressed by the continuous duty operation and develop means to optimize the design for high power.
* Detail the notional design sufficiently to demonstrate that the design concepts are valid and will result in a continuous duty cycle transducer capable of significant output power.
* Determine the effects of duty cycle on the fatigue characteristics of all components of the transducer.

PHASE II:
* Complete design and then fabricate a prototype transducer to demonstrate continuous operation.
* Validate the model developed to describe the transducer using measured data on the prototype and then exercise the model to determine performance and stresses expected when the transducer is part of a sonar array.
* Assess each critical component of the transducer to determine if additional power can be tolerated and refresh the design with this information. Fabricate a second prototype with knowledge learned.
* Identify a transition target and modify the transducer design for that specific application.
* Based on the anticipated application to be pursued there may be a need to treat the Phase II in a classified manner.

PHASE III:
* Complete design of a transducer tailored for a specific application.
* Fabricate a prototype transducer and after testing and model validation, fabricate a partial array of 16 transducers to form a 4x4 array.
* Test the partial array at high power and determine the maximum achievable drive level remaining within linear limits of performance.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Continuous duty transducers have a use in both sonar and other applications. In addition to the Naval sonar application there is a technology area involving ultrasonic cleaning and vibratory devices such as hand-held jack hammers and dental appliances that need and utilize continuous duty operation.

REFERENCES:
1. C.H. Sherman and J.L. Butler, "Transducers and Arrays for Underwater Sound", Springer (2007)

2. R.J. Urick, "Principles of Underwater Sound", Peninsula Publishing (1983)

3. A.D. Waite, "Sonar for Practising Engineers", John Wiley (2002)

KEYWORDS: ASW; transducers; continuous duty; high power; acoustics; battlespace environment

** TOPIC AUTHOR (TPOC) **

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