Ultrasonic Underwater Transmission of Composite Turbine Blade Structural Health

Abstract

A health monitoring approach is investigated for hydrokinetic turbine blade applications. In-service monitoring is critical due to the difficult environment for blade inspection and the cost of inspection downtime. Composite blade designs provide a medium for embedding sensors into the blades for in-situ health monitoring. The major challenge with in-situ health monitoring is transmission of sensor signals from the remote rotating reference frame of the blade to the system monitoring station. In the presented work, a novel system for relaying in-situ blade health measurements is described and demonstrated. An ultrasonic communication system is used to transmit health data underwater from the rotating frame of the blade to a fixed relay station. Data are then broadcast via radio waves to a remote monitoring station. Results indicate that the assembled system can transmit simulated sensor data with an accuracy of ±5% at a max sampling rate of 500 samples/sec. A power investigation of the transmitter within the blade shows that continuous max-sampling operation is only possible for short durations (~days), and is limited due to the capacity of the battery power source. For a 1000 mA-hr battery to last two years, the transmitter must be operated with a duty cycle of 368, which means data are acquired and transmitted every 59 seconds. Finally, because the data transmission system is flexible, being able to operate at high sample rate for short durations and lower sample rate/high duty cycle for long durations, it is well-suited for short-term prototype and environmental testing, as well as long-term commercially-deployed hydrokinetic machines.

Meeting Name

Industrial and Commercial Applications of Smart Structures Technologies (2012: Mar. 11, San Diego, CA)

Department(s)

Mechanical and Aerospace Engineering

Second Department

Electrical and Computer Engineering

Third Department

Materials Science and Engineering

Keywords and Phrases

Composites; Ultrasonics; Sensors; Transmitters; Inspection; Power Supplies; Relays; Data Transmission; Telecommunications

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2012 SPIE, All rights reserved.

Publication Date

01 Jan 2012

Link to Full Text

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