Abstract: Methods, systems and apparatuses are disclosed for interrogating characteristics of a substrate material surface and sub-surface by evaluating Terahertz output signals generated by non-Terahertz, optical source inputs.

Abstract: A system for measuring strain includes an optical fiber having a central portion secured between two fixed points. A first light source outputs light at a first frequency and a second light source outputs light at a second different frequency. The two light sources are both coupled to a first end of the optical fiber. A back scatter detector is also coupled to the first end to receive a return light signal from the optical fiber and outputs a signal based thereon. A forward scatter detector is coupled to a second end of the optical fiber to receive a forward light signal from the optical fiber and outputs a signal based thereon. A processor receives the signals from the back scatter detector and the forward scatter detector and generates an output signal proportional to the strain between the two fixed points based on the received signals.

Abstract: A composite structure having an embedded sensing system is provided, along with corresponding systems and methods for monitoring the health of a composite structure. The composite structure includes composite material and an optical fiber disposed within the composite material. The optical fiber includes a plurality of quantum dots for enhancing its non-linear optical properties. The quantum dots may be disposed in the core, in the cladding and/or on the surface of the optical fiber. The optical fiber is configured to support propagation of the signals and to be sensitive to a defect within the composite material. The quantum dots create a non-linear effect, such as a second order effect, in response to the defect in the composite material. Based upon the detection and analysis of the signals including the non-linear effect created by the quantum dots, a defect within the composite material may be detected.

Abstract: An apparatus, system, and method are disclosed for nonlinear optical surface sensing with a single thermo-electric detector. In particular, the system includes at least two signal sources that are co-aligned to propagate photons to the same location on a surface. The system also includes at least one focusing element that focuses a sequence of photons that is reflected from the location on the surface. In addition, the system includes at least one frequency selective electromagnetic detector that detects the sequence of photons that are focused from the focusing element(s). When the frequency selective electromagnetic detector senses a photon, the frequency selective electromagnetic detector emits an electrical pulse that has a voltage that is proportional to the energy level of the photon. Additionally, the system includes a processor that processes the electrical pulses, and de-multiplexes the sequence of emitted electrical pulses based on the electrical pulse voltage of the electrical pulses.

Abstract: A method for monitoring and diagnosing the health of a structure. The method includes providing a plurality of damage monitoring units each having at least one actuator, at least one sensor and a data collection device. The sensors are arranged and disposed to measure vibration produced by the actuator and provide a signal corresponding to the measured vibration to the data collection device. The actuator is activated and the vibration is measured with the sensor. The signal is compared to a reference signal and a damage index value is determined in response to the comparison between the signal and reference signal. The damage index value is transmitted for each vibratory path to a central processing device and the damage index values are analyzed for the plurality of damage monitoring units to determine the location of damage to the structure.

Abstract: A composite structure having an embedded sensing system is provided, along with corresponding systems and methods for monitoring the health of a composite structure. The composite structure includes composite material and an optical fiber disposed within the composite material. The optical fiber includes a plurality of quantum dots for enhancing its non-linear optical properties. The quantum dots may be disposed in the core, in the cladding and/or on the surface of the optical fiber. The optical fiber is configured to support propagation of the signals and to be sensitive to a defect within the composite material. The quantum dots create a non-linear effect, such as a second order effect, in response to the defect in the composite material. Based upon the detection and analysis of the signals including the non-linear effect created by the quantum dots, a defect within the composite material may be detected.

Abstract: A composite structure having an embedded sensing system is provided, along with corresponding systems and methods for monitoring the health of a composite structure. The composite structure includes composite material and an optical fiber disposed within the composite material. The optical fiber includes a plurality of quantum dots for enhancing its non-linear optical properties. The quantum dots may be disposed in the core, in the cladding and/or on the surface of the optical fiber. The optical fiber is configured to support propagation of the signals and to be sensitive to a defect within the composite material. The quantum dots create a non-linear effect, such as a second order effect, in response to the defect in the composite material. Based upon the detection and analysis of the signals including the non-linear effect created by the quantum dots, a defect within the composite material may be detected.

Abstract: An apparatus, system, and method are disclosed for nonlinear optical surface sensing with a single thermo-electric detector. In particular, the system includes at least two signal sources that are co-aligned to propagate photons to the same location on a surface. The system also includes at least one focusing element that focuses a sequence of photons that is reflected from the location on the surface. In addition, the system includes at least one frequency selective electromagnetic detector that detects the sequence of photons that are focused from the focusing element(s). When the frequency selective electromagnetic detector senses a photon, the frequency selective electromagnetic detector emits an electrical pulse that has a voltage that is proportional to the energy level of the photon. Additionally, the system includes a processor that processes the electrical pulses, and de-multiplexes the sequence of emitted electrical pulses based on the electrical pulse voltage of the electrical pulses.

Abstract: A method for reducing wear between two surfaces in sliding contact with one another includes introducing nanoparticles between the two surfaces in an amount and having a composition that results in shear lines being generated within at least one agglomerated wear particle that is generated between the two surfaces as a result of the sliding contact, and subjecting the agglomerated wear particles to at least one load, using at least one of the two surfaces, such that the agglomerated wear particles disassemble along the shear lines into multiple smaller wear particles.

Abstract: An apparatus may have a multilayered support base having a structural section made up of operating components and a function support section. The function support section may have transmission paths and components to supply thermal, power transmission, information and communication paths, along with other functions. At least some of the components may be heat generating and may have a thermal interface surface which may be in operating and heat conductive relationship with a heat conductive substrate/routing section which may have operative connections to the multilayered support base. Some of the components may transmit and receive with one another through the substrate/routing section.

Abstract: A method for monitoring and diagnosing the health of a structure. The method includes providing a plurality of damage monitoring units each having at least one actuator, at least one sensor and a data collection device. The sensors are arranged and disposed to measure vibration produced by the actuator and provide a signal corresponding to the measured vibration to the data collection device. The actuator is activated and the vibration is measured with the sensor. The signal is compared to a reference signal and a damage index value is determined in response to the comparison between the signal and reference signal. The damage index value is transmitted for each vibratory path to a central processing device and the damage index values are analyzed for the plurality of damage monitoring units to determine the location of damage to the structure.

Abstract: The apparatus and method of the present invention provide a quick, simple and accurate manner in which to measure the dimensions or characteristics of a hole without contacting the hole. The apparatus and method of the present invention also automatically detect different materials defining the hole and, therefore, the location of the interface where the materials meet. To measure the characteristics of the hole, the apparatus and method measure the intensities of the light reflected off the hole wall. In addition, the light directed toward the hole wall by the optical fiber may be of the type, such as collimated or focused, to provide distinct reflections that are received and measured by the optical receiver to supply accurate measurements of the hole characteristics.

Abstract: Disclosed is a method that utilizes optics to measure a hole depth in a workpiece. The method involves placing a light recording apparatus and a light source apparatus proximate a hole. Light is then emitted from the light source apparatus and is directed into the hole. This illumination of the hole allows an image of the side surface of the hole that is at the greatest distance from the light recording apparatus to be recorded. Then, the apparent diameter of the image is calculated. The apparent diameter of the image, in turn, is compared to the known diameter of the hole in order to calculate the distance between a reference datum in the light recording apparatus and the far side surface of the hole. Once this distance is determined, the hole depth is calculated by accounting for the distance between the reference datum and the workpiece surface.

Abstract: Disclosed is a method that utilizes optics to measure a hole depth in a workpiece. The method involves placing a light recording apparatus and a light source apparatus proximate a hole. Light is then emitted from the light source apparatus and is directed into the hole. This illumination of the hole allows an image of the side surface of the hole that is at the greatest distance from the light recording apparatus to be recorded. Then, the apparent diameter of the image is calculated. The apparent diameter of the image, in turn, is compared to the known diameter of the hole in order to calculate the distance between a reference datum in the light recording apparatus and the far side surface of the hole. Once this distance is determined, the hole depth is calculated by accounting for the distance between the reference datum and the workpiece surface.

Abstract: The apparatus and method of the present invention provide a quick, simple and accurate manner in which to measure the dimensions or characteristics of a hole without contacting the hole. The apparatus and method of the present invention also automatically detect different materials defining the hole and, therefore, the location of the interface where the materials meet. To measure the characteristics of the hole, the apparatus and method measure the intensities of the light reflected off the hole wall. In addition, the light directed toward the hole wall by the optical fiber may be of the type, such as collimated or focused, to provide distinct reflections that are received and measured by the optical receiver to supply accurate measurements of the hole characteristics.

Abstract: A system such as for sensing strain or temperature of an aircraft and for transmitting information in communication systems. A sensor array includes a first light responsive Bragg grating sensor having a first operating bandwidth and a second light responsive Bragg grating sensor having a second operating bandwidth. Each sensor modifies light provided to it at a wavelength indicative of changes in strain or temperature. The second sensor operates within a bandwidth which is different from the operating bandwidth of the first sensor. A tunable light source such as an LED and tunable etalon provides light for illuminating the first and second sensors, the provided light having a wavelength which varies within a band including the first and second bandwidths. A detecting circuit provides signals representative of light modified by the first and second sensors. A processor processes the representative signals to determine the strain and/or temperature.

Abstract: The apparatus and associated method of the present invention remotely detects structural defects in a workpiece by monitoring the electrical continuity of thin crack wires deposited on or within the workpiece in response to a communication from a remote interrogation device. As a crack, delamination or other structural defect forms or propagates in a structural member or other workpiece, a crack wire located in the vicinity of the crack breaks. In addition to the crack wires, the defect sensing apparatus includes a transponder and a discontinuity sensor for detecting a discontinuity along the crack wire. In order to inspect the workpiece, a maintenance technician positions a remote interrogation device in proximity with the workpiece under inspection. The interrogation signals provided by the remote interrogation device are received by the transponder and serve to power the defect sensing apparatus.

Abstract: A fiber optic sensing system and method comprises a continuous optical fiber including at least three mirrors defining at least two contiguous optical cavities. Preferably, each optical cavity has a unique length so that the reflected optical signal associated with a given optical cavity will have a unique phase difference or wavelength allowing each of the respective optical signals to be selectively detected. A physical phenomenon acting on a given optical cavity can be sensed by determining changes in the respective optical signal reflected from that optical cavity. This sensing system allows a single optical fiber to include both integrating and point sensors. In addition, this system can be incorporated in smart structures.

Abstract: A system and method for absolute, high resolution and accurate strain measurement includes a low-coherence light source (12) transmitting light through a strain sensor (18) and into an interferometer (26). The interferometer (26) has a high-coherence light source (48) that parallels the light from the low-coherence light source (12). The output of the interferometer is detected by a photodetector (46). The photodetector (46) is connected to a phase measuring circuit (30), that is in communication with a controller (28). The controller (28) is also connected to a motor (44) that adjusts the optical path lengths in the interferometer (38). The phase change in the high-coherence source from the fringe pattern (68) of the strain sensor (18) before and after a strain is applied to the device under test is used to determine the strain.