Abstract: A method of forming an energy harvesting device comprises supporting an outer peripheral edge of a disc spring using a support element that allows oscillations of the disc spring. A first preload force is applied to the disc spring and directed along its axial center. During application of the first preload force, a piezoelectric material is fixedly secured with a surface of the disc spring. A second preload force is applied to the disc spring to thereby provide a predetermined reduction of a stiffness of the disc spring. The reduction of the stiffness corresponds to an increased sensitivity to low-frequency components of vibrational energy received by the energy harvesting device.

Abstract: An energy harvesting apparatus and method that is especially well suited for harvesting low frequency broadband vibration energy from a vibrating structure is presented. The apparatus includes a pair of disc springs that are arranged in an opposing relationship. A threaded fastening member and a threaded nut extend through apertures in each of the disc springs and enable a predetermined preload force to be applied to the disc springs. The preload effectively “softens” the disc springs, thus heightening the sensitivity of the disc springs to low frequency, low amplitude vibration energy. A piezoelectric material ring is secured to each of the disc springs. Each piezoelectric material ring experiences changes in strain as its associated disc spring deflects in response to vibration energy experienced from a vibrating structure.

Abstract: An illustrative embodiment of a temperature-activated voltage generator includes a generator housing having a housing interior; a flexible, temperature-sensitive bimetallic element disposed in the housing interior; and a piezoelectric element carried by the generator housing. The bimetallic element is positional between a first position wherein the bimetallic element disengages the piezoelectric element and a second position wherein the bimetallic element engages the piezoelectric element. Electrical voltage output leads are electrically connected to the piezoelectric element. A voltage-generating method is also disclosed.

Abstract: An illustrative embodiment of a temperature-activated voltage generator includes a generator housing having housing interior; a flexible, temperature-sensitive bimetallic element disposed in the housing interior; and a piezoelectric element carried by the generator housing. The bimetallic element is positional between first position wherein the bimetallic element disengages the piezoelectric element, and a second position wherein the bimetallic element engages the piezoelectric element. Electrical voltage output leads are electrically connected to the piezoelectric element. A voltage-generating method is also disclosed.

Abstract: An illustrative embodiment of a temperature-activated voltage generator includes a generator housing having a housing interior; a flexible, temperature-sensitive bimetallic element disposed in the housing interior; and a piezoelectric element carried by the generator housing. The bimetallic element is positional between a first position wherein the bimetallic element disengages the piezoelectric element and a second position wherein the bimetallic element engages the piezoelectric element. Electrical voltage output leads are electrically connected to the piezoelectric element. A voltage-generating method is also disclosed.

Abstract: An illustrative embodiment of a temperature-activated voltage generator includes a generator housing having a housing interior; a flexible, temperature-sensitive bimetallic element disposed in the housing interior; and a piezoelectric element carried by the generator housing. The bimetallic element is positional between a first position wherein the bimetallic element disengages the piezoelectric element and a second position wherein the bimetallic element engages the piezoelectric element. Electrical voltage output leads are electrically connected to the piezoelectric element. A voltage-generating method is also disclosed.

Abstract: Structural health monitoring apparatuses and methods are disclosed. One or more structural health sensors may be used to disconnect and/or connect one or more RFID chips to an antenna such that wireless communication with the one or more RFID chips (or the absence of wireless communication) through the antenna indicates the structural health status. Example structural health sensors may be moisture detecting or fracture detecting. A remote reader may be used to establish the wireless communication with the one or more RFID chips to determine the structural health. The sensors and RFID chips may be passive and powered through the wireless communication from the remote reader. Such apparatuses and methods may be applied to any large structures requiring regular inspection, such as aircraft, ships, automobiles or buildings.

Abstract: An energy harvesting apparatus and method that is especially well suited for harvesting low frequency broadband vibration energy from a vibrating structure is presented. The apparatus includes a pair of disc springs that are arranged in an opposing relationship. A threaded fastening member and a threaded nut extend through apertures in each of the disc springs and enable a predetermined preload force to be applied to the disc springs. The preload effectively “softens” the disc springs, thus heightening the sensitivity of the disc springs to low frequency, low amplitude vibration energy. A piezoelectric material ring is secured to each of the disc springs. Each piezoelectric material ring experiences changes in strain as its associated disc spring deflects in response to vibration energy experienced from a vibrating structure.

Abstract: Structural health monitoring apparatuses and methods are disclosed. One or more structural health sensors may be used to disconnect and/or connect one or more RFID chips to an antenna such that wireless communication with the one or more RFID chips (or the absence of wireless communication) through the antenna indicates the structural health status. Example structural health sensors may be moisture detecting or fracture detecting. A remote reader may be used to establish the wireless communication with the one or more RFID chips to determine the structural health. The sensors and RFID chips may be passive and powered through the wireless communication from the remote reader. Such apparatuses and methods may be applied to any large structures requiring regular inspection, such as aircraft, ships, automobiles or buildings.

Abstract: Apparatus, systems, and methods for inspecting and monitoring bolted joints of metallic and composite structures for defects such as delamination and fatigue cracking are provided that incorporate ultrasonic transducers with load bearing washers. These active washers may be used for inspecting and monitoring a structure beneath such load bearing fasteners as bolts and nuts. Active washers may be used for continuous, periodic, and controlled inspections of bolted joints. Ultrasonic transducers may be permanently applied to a surface of a washer or recessed in a cavity on a surface of the washer. Inspection signals may be transmitted from ultrasonic transducers into a structure and reflected in pulse-echo application or received by another active washer on the opposing side of the structure in a through-transmission application.

Abstract: An apparatus for establishing a substantially unitary connecting structure including a generally flat conductor member carrying a first plurality of first electrical conductors and a second conductor member carrying a second plurality of second electrical conductors includes: (a) an electrical connecting structure configured for receiving the second conductor member to establish electrical connection between at least one first electrical conductor of the first plurality of first electrical conductors and at least one second electrical conductor of the second plurality of second electrical conductors; (b) a generally inflexible support structure; and (c) at least one connecting member traversing the flat conductor member and cooperating with the electrical connecting structure and the support structure for capturing the flat conductor member between the connecting structure and the support structure in an installed orientation.

Abstract: An apparatus for establishing a substantially unitary connecting structure including a generally flat conductor member carrying a first plurality of first electrical conductors and a second conductor member carrying a second plurality of second electrical conductors includes: (a) an electrical connecting structure configured for receiving the second conductor member to establish electrical connection between at least one first electrical conductor of the first plurality of first electrical conductors and at least one second electrical conductor of the second plurality of second electrical conductors; (b) a generally inflexible support structure; and (c) at least one connecting member traversing the flat conductor member and cooperating with the electrical connecting structure and the support structure for capturing the flat conductor member between the connecting structure and the support structure in an installed orientation.

Abstract: Structural analysis systems and methods are disclosed. One embodiment provides a method for analyzing a structure includes receiving damage image data; converting the received image data into analysis data in an analyzable format; performing a structural analysis on the analysis data; and outputting the results of the structural analysis. The system includes a computer or other processing device that is capable of analyzing a structure. The system receives damage image data; converts the received image data into analysis data in an analyzable format; performs a structural analysis on the analysis data; and outputs the results of the structural analysis.

Abstract: An energy harvesting apparatus and method that is especially well suited for harvesting low frequency broadband vibration energy from a vibrating structure is presented. The apparatus includes a pair of disc springs that are arranged in an opposing relationship. A threaded fastening member and a threaded nut extend through apertures in each of the disc springs and enable a predetermined preload force to be applied to the disc springs. The preload effectively “softens” the disc springs, thus heightening the sensitivity of the disc springs to low frequency, low amplitude vibration energy. A piezoelectric material ring is secured to each of the disc springs. Each piezoelectric material ring experiences changes in strain as its associated disc spring deflects in response to vibration energy experienced from a vibrating structure.

Abstract: Structural analysis systems and methods are disclosed. One embodiment provides a method for analyzing a structure includes receiving damage image data; converting the received image data into analysis data in an analyzable format; performing a structural analysis on the analysis data; and outputting the results of the structural analysis. The system includes a computer or other processing device that is capable of analyzing a structure. The system receives damage image data; converts the received image data into analysis data in an analyzable format; performs a structural analysis on the analysis data; and outputs the results of the structural analysis.

Abstract: A phased array sensor assembly is presented that can be permanently adhered to and impart ultrasonic waves to a structural surface and receive ultrasonic waves from a structural surface. The sensor assembly includes piezo-electric disks, a plurality of electrically conductive epoxy film adhesive contacts positioned such that an electrical coupling is formed with the piezo-electric disks, piezo transducer flex wire trace circuits aligned to be electrically coupled respectively with the electrically conductive epoxy film adhesive contacts on one end and including a plurality of wire trace electrical contact pads on the other end, and a flexible polyimide layer. The polyimide layer includes laser ablated areas for exposing the contact pads such that they can be electrically coupled with an external device.

Abstract: A connector pad is provided having a base, a top opposite the base, and tapered sidewalls therebetween. The tapering minimizes stress concentrations when the connector pad is bonded into, or on the surface of a structure. The connector pad consists of a plurality of structural load carrying plies suitable for sandwiching a flat structurally integrated wiring array therebetween. A plurality of plated through holes formed in the connector pad enable access to the wiring array therein.

Abstract: A piezoelectric device connected to a vibration source converts vibration energy to electrical current. A plurality of pairs of oppositely polarized piezoelectric wafers deflect to produce an electrical current. Each pair of wafers are arranged back-to-back and electrically joined together. The plurality of pairs of wafers are each connected to a set of micro-machined parts. Each pair of wafers form a bimorph, configured as a cantilevered beam attached to a set of parts to form an element. Each cantilevered beam has a mass weighted first end and is fixedly attached to one or more flexible sheaths on a second end. A plurality of elements form a cell unit. A plurality of cell units form an array. The electrical current produced varies by the number of elements per cell unit, and/or with the number of cell units per array.

Abstract: A connector pad is provided having a base, a top opposite the base, and tapered sidewalls therebetween. The tapering minimizes stress concentrations when the connector pad is bonded into, or on the surface of a structure. The connector pad consists of a plurality of structural load carrying plies suitable for sandwiching a flat structurally integrated wiring array therebetween. A plurality of plated through holes formed in the connector pad enable access to the wiring array therein.

Abstract: An energy harvesting device is provided. The energy harvesting device includes structural members covered with piezoelectric material resonating at different primary frequencies. As the structure to which the energy harvesting device is secured vibrates over a range of frequencies, more than one member resonates or is close to resonance. As such, multiple members work simultaneously to create electrical energy.