Description:
Reference #: 00587
The University of South Carolina is offering licensing opportunities for this innovative method for actuating localized electric fields with large reductions in wiring within a continuous array of sensors.
Background:
Structural health monitoring (SHM) is an emerging field in which smart materials interrogate structural components to predict failure, expedite needed repairs, and thus increase the useful life of the components. In the application of this technological approach, the use of the piezoelectric materials to convert electrical signals into acoustic energy (and vice versa) has found many industrial applications for sensors. One method of using these kinds of materials is in the form of piezoelectric wafer active sensors (PWAS), which uses a capacitor approach to create the electric field needed for excitation. PWAS have been applied to substrates and demonstrate the ability to detect and locate cracking, corrosion, and disbanding through use of pitch-catch, pulse-echo, electro/mechanical impedance, and phased array technology.
The Challenge/Motivation:
Currently, for a 2-D array with or without electrode slicing, a signal must be bonded to the exposed electrode surface for actuation and reception of signals. For a 64 element array, this approach requires 65 electrical connections (one for each sensor and one for ground). In aerospace and the astrospace industry, reduction in weight is critical, and even though each array requires only a small amount of weight of wiring (and solder), the summation of weight from arrays located throughout the vehicles will increase the weight somewhat. Additionally, the task of creating arrays with larger amounts of elements will become more and more cumbersome. The current largest array feasible is 64 elements, but the next size up will employ 256 sensors. These increases create a need for a simple method of actuation and reception that employs minimal wiring.
State Of Art:
Localization of electric fields via signal electrode separation has successfully demonstrated the ability to actuate portions of a continuous medium. In this manner, 2-D arrays can now be fabricated with higher accuracy in the location of the effective sensor relative to the other effective sensor within the array. The new limitation to the larger arrays is the large amount of wiring involved (reference Dr. Yu’ thesis). This aspect will only become worse as data acquisition technology allows for more rapid collection of data leading inevitably towards larger and larger arrays.
Advantages and Benefits:
This invention will allow for a reduction in the number of wirings required for phased array technology sensor geometry. The reduction in number of wirings makes weight reduction possible because the weight of wiring (and solder) is reduced.
Potential Applications:
Design of electrical fields within a continuous medium for structural health monitoring (SHM) applications.