Remote self-powered structure monitor
First Claim
1. A remote structure monitor, for detecting structural crack beginnings and growth in a rotating metal structure, comprising:
- a piezo-electric acoustic emission sensor on the rotating metal structure for detecting non repetitive high frequency acoustic emission events of 1 to 10 MHz from stress wave acoustic emission energy that comes from said structural crack beginnings and growth and for converting the acoustic emission energy into electrical signals;
a signal processor, connected to said piezo acoustic emission sensor for receiving the electrical signals prom said emission sensor, said piezo-electric acoustic emission sensor being formed from a plurality of piezo-electric layers and a plurality of elastomeric layers situated between the plurality of piezo-electric layers, such that the piezo-electric and elastomeric layers are stacked on one another alternately in that one elastomeric layer is situated between adjacent piezo-electric layers to form a layered sensor;
a power storage device being positioned on said layered sensor to provide an inertial load, wherein said sensor outputs the electrical power signals due to compression, stretching and/or bending of the plurality of piezo-electric layers, caused by the vibration of said rotating metal structure and enhanced by said inertial load.
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Accused Products
Abstract
An acoustic rotor monitor that is an autonomous self-powered measurement instrument which can detect embedded and hidden fatigue cracks in remotely inaccessible devices such as helicopter rotor system components. A predictive maintenance-related problem for rotor craft is the detection of fatigue cracks as a continuous real-time monitoring process under dynamic rotor system loading conditions. The rotor monitor focuses on the embedding an acoustic emission-based smart sensor directly into the rotor system to measure the high frequency stress waves indicating that a structural crack has propagated as a "self-powered" measurement without reducing structural integrity.
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Citations
6 Claims
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1. A remote structure monitor, for detecting structural crack beginnings and growth in a rotating metal structure, comprising:
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a piezo-electric acoustic emission sensor on the rotating metal structure for detecting non repetitive high frequency acoustic emission events of 1 to 10 MHz from stress wave acoustic emission energy that comes from said structural crack beginnings and growth and for converting the acoustic emission energy into electrical signals; a signal processor, connected to said piezo acoustic emission sensor for receiving the electrical signals prom said emission sensor, said piezo-electric acoustic emission sensor being formed from a plurality of piezo-electric layers and a plurality of elastomeric layers situated between the plurality of piezo-electric layers, such that the piezo-electric and elastomeric layers are stacked on one another alternately in that one elastomeric layer is situated between adjacent piezo-electric layers to form a layered sensor; a power storage device being positioned on said layered sensor to provide an inertial load, wherein said sensor outputs the electrical power signals due to compression, stretching and/or bending of the plurality of piezo-electric layers, caused by the vibration of said rotating metal structure and enhanced by said inertial load. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification