Abstract: A system and method for evaluating a bond is provided. The system uses an underwater spark discharge to generate a compression wave in a first vessel containing a liquid. The system further includes a second vessel in which a vacuum is pulled to hold the first vessel against a bonded structure being inspected. The compression wave is directed to propagate from the liquid into the bonded structure to apply a known force to the bond being inspected.

Abstract: An example system for inspecting a surface includes a laser, an optical system, a gated camera, and a control system. The laser is configured to emit pulses of light, with respective wavelengths of the pulses of light varying over time. The optical system includes at least one optical element, and is configured to direct light emitted by the laser to points along a scan line one point at a time. The gated camera is configured to record a fluorescent response of the surface from light having each wavelength of a plurality of wavelengths at each point along the scan line. The control system is configured to control the gated camera such that an aperture of the gated camera is open during fluorescence of the surface but closed during exposure of the surface to light emitted by the laser.

Abstract: A flexoelectricity ultrasonic (UT) transducer imaging system is disclosed comprising a polytetrafluoroethylene (PTFE) layer, a plurality of flexoelectricity UT transducers, and a multiplexer. The PTFE layer includes a front and back surface and the plurality of flexoelectricity UT transducers is attached to the back surface of the PTFE layer. Each UT transducer has a front-end and back-end and the front-end of each flexoelectricity UT transducer is attached to the back surface of the PTFE layer. The flexoelectricity UT transducers are arranged along the back surface of the PTFE layer as a two-dimensional array and each flexoelectricity UT transducer is configured to vibrate in a normal direction to the back surface of the PTFE layer. The multiplexer in signal communication with each flexoelectricity UT transducer, where the flexoelectricity UT transducers are sandwiched between the multiplexer and the PTFE layer.

Abstract: An example laser system includes a laser, a plurality of pulse stretchers coupled together in series, a feedback module, and a lens assembly. The plurality of pulse stretchers is configured to stretch pulse widths of laser pulses provided by the laser and to output stretched laser pulses. The feedback module includes a pulse delay comparator that is configured to compare a first laser pulse of the laser pulses to a corresponding first stretched laser pulse of the stretched laser pulses. The feedback module also includes a computing device that is configured to determine, based on a result of the comparing by the pulse delay comparator, an adjustment to a pulse stretcher of the plurality of pulse stretchers, and apply the adjustment to the pulse stretcher so as to modify a shape of a second stretched laser pulse of the stretched laser pulses.

Abstract: A method of manufacturing a prepreg composition includes disposing a plurality of core/shell quantum dots on or in a resin matrix of the prepreg composition. The quantum dots may include an inner core that when excited by light of a first wavelength emits a detectable luminescent signal, and an outer shell that blocks light of the first wavelength from reaching the inner core when the outer shell is intact. A method of determining the suitability of a pre-impregnated composite fiber material for incorporation into a composite structure and a method of detecting damage to a prepreg composition due to ultraviolet radiation exposure utilizing the core/shell quantum dots are provided.

Abstract: An example system for inspecting a surface includes a laser, an optical system, a gated camera, and a control system. The laser is configured to emit pulses of light, with respective wavelengths of the pulses of light varying over time. The optical system includes at least one optical element, and is configured to direct light emitted by the laser to points along a scan line one point at a time. The gated camera is configured to record a fluorescent response of the surface from light having each wavelength of a plurality of wavelengths at each point along the scan line. The control system is configured to control the gated camera such that an aperture of the gated camera is open during fluorescence of the surface but closed during exposure of the surface to light emitted by the laser.

Abstract: A system for evaluating a bond includes a first electrode and a second electrode that are spaced apart from one another. The system also includes a sacrificial material layer positioned proximate to a surface of a bonded structure that includes the bond. The system also includes a power source configured to cause the first and second electrodes to generate an electrical arc that at least partially ablates the sacrificial material layer as part of a non-destructive inspection of the bond.

Abstract: Systems and methods are provided for enhanced vacuum bags. One embodiment is a method that includes placing a laminate comprising uncured fiber reinforced polymer onto a mandrel, laying up a vacuum bag, which includes integral ultrasonic transducers within a gas-impermeable layer, atop the laminate, and sealing the vacuum bag to the mandrel. The method also includes drawing a vacuum on the laminate via the vacuum bag, removing gas between the integral ultrasonic transducers and the laminate, and interrogating the laminate with the integral ultrasonic transducers.

Abstract: A system and method for determining a width of a gap in a structure is provided. The system uses an underwater spark discharge to generate a compression wave in a first vessel containing a liquid. The system further includes a second vessel in which a vacuum is pulled to hold the first vessel against the structure. The compression wave is directed to propagate from the liquid into the structure and is detected after it propagates through the structure including the gap.

Abstract: A method for real-time surface imperfection detection for additive manufacturing and 3-D printing parts is provided. The method includes directing a first light radiation using one or more illumination sources, wherein the first light radiation illuminates a target area of a part being manufactured in a uniform chromatic light such that the target area appears to have a substantially uniform monochromatic color; capturing a current image of a second light radiation that is scattered or reflected by the target area using one or more feedback cameras; and analyzing the current image of the second light radiation using at least one of the one or more feedback camera with a previously acquired image to determine whether a surface imperfection exists or does not exist.

Abstract: A prepreg composition includes a plurality of core/shell quantum dots that exhibit an increase in detectable luminescence when the prepreg composition has been exposed to an amount of UV radiation that would render the prepreg composition unsuitable for use in fabricating composite structures, thereby greatly simplifying detection of compromised prepreg materials that for example, may have been inadvertently and undesirably exposed to UV radiation during storage or handling. A method of manufacturing a prepreg composition includes forming a bed of fibers, contacting the fiber bed with a resin matrix, and disposing a plurality of core/shell quantum dots on or in the resin matrix.

Abstract: A method for real-time surface imperfection detection for additive manufacturing and 3-D printing parts is provided. The method includes directing a first light radiation using one or more illumination sources, wherein the first light radiation illuminates a target area of a part being manufactured in a uniform chromatic light such that the target area appears to have a substantially uniform monochromatic color; capturing a current image of a second light radiation that is scattered or reflected by the target area using one or more feedback cameras; and analyzing the current image of the second light radiation using at least one of the one or more feedback camera with a previously acquired image to determine whether a surface imperfection exists or does not exist.

Abstract: A system for charging vehicles. The system includes a renewable energy collection device configured to collect renewable energy from one or more renewable energy sources. The system includes various components configured to store and deliver the electrical energy for dispensing. The system is further configured to receive energy from a power grid. The energy from the power grid can supplement the energy available in the system and/or supply the energy for dispensing.

Abstract: A method of inspecting a structure during additive manufacturing of the structure and additive manufacturing systems are presented. An additive manufacturing system comprises additive manufacturing equipment comprising a casing and an additive manufacturing head configured to form a plurality of layers of a structure within the casing; and an x-ray backscatter imaging system configured to send an x-ray beam into a structure formed within the additive manufacturing equipment and detect scattered x-rays for imaging and analysis of the structure during fabrication.

Abstract: A system and method for detecting an anomaly in a structure using an adaptive filter to compensate for variations in piezoelectric transducer performance due to environmental factors such as temperature. A first voltage signal having a first amplitude is sent to a reference piezoelectric actuator. Thereafter, a first reference voltage signal is received from a reference piezoelectric receiver which is acoustically coupled to detect the guided wave generated by the reference piezoelectric actuator. A second amplitude is determined using an optimization algorithm of an adaptive filter to compensate for nonlinear behavior of the reference piezoelectric actuator and receiver based on the first reference voltage signal. Then the adaptive filter sends a second voltage signal having the second amplitude to the reference and test piezoelectric actuators. Reference and test voltage signals are received from the reference and test piezoelectric receivers in response to the second voltage signal.

Abstract: Renewable energy charging stations, systems, and methods are disclosed for capturing storing and delivering large amounts of renewable electrical energy from a renewable energy source to vehicles including passenger aircraft using charging circuits in communication with a demultiplexer and high-temperature superconducting cables to deliver required large electrical charges at fast charging rates safely and at low temperatures.

Abstract: Systems and methods of providing power to high-voltage sensors in power-limited environments through environmental energy harvesting are disclosed. The systems and methods are configured to intermittently power high-voltage sensors by repeatedly releasing stored energy in bursts. An environmental energy harvesting device generates a low-voltage power supply and is coupled to one or more capacitors to charge the capacitors to a high-voltage threshold. After such high-voltage threshold has been reached, the capacitors are discharged to provide a high-voltage power burst to a high-voltage sensor configured to inspect a component and generate an inspection result signal. The inspection result signal is received by an output module, which may further store or transmit to an external receiver a data signal indicating the inspection results.

Abstract: Method, apparatus, system, and computer program product for inspecting a joining feature on an object. A portable housing with an x-ray system is moved along the joining feature on the object. The x-ray system is controlled to direct an x-ray beam through an opening in the portable housing to scan an area of the object containing the joining feature as the portable housing moves along the joining feature on the object. Sensor data generated from a backscatter detected by a sensor system is received. The backscatter is generated in response to the x-ray beam encountering the area of the object including the joining feature. A determination is made as to whether an inconsistency is present in the area of the object including the joining feature using the sensor data.

Abstract: Disclosed herein is an x-ray backscatter apparatus for non-destructive inspection of a part. The x-ray backscatter apparatus comprises an x-ray source and an x-ray filter. The x-ray filter comprises a plurality of emission apertures and a detection aperture. The x-ray backscatter apparatus further comprises an x-ray intensity sensor that is fixed to the x-ray filter over the detection aperture such that any portion of an unfiltered x-ray emission filtered into the detection aperture is detected by the x-ray intensity sensor. The x-ray backscatter apparatus additionally comprises an emission alignment adjuster that is operable to adjust a position of the unfiltered x-ray emission relative to the plurality of emission apertures and the detection aperture in response to a position, relative to the detection aperture, of a peak intensity of the unfiltered x-ray emission passing into the detection aperture, detected by the x-ray intensity sensor.

Abstract: Systems and methods for bondline inspection using mechanical wave measurement and gas excitation. A cost-effective optical interferometry technique is used to measure mechanical waves generated by gas excitation, which measurements may be used to verify the strength of a bondline of a composite bonded structure. A gas gun which produces a high-pressure short-pulsewidth gas pulse at the front free surface of the composite material. A velocity interferometer system for any reflector (VISAR) is synchronized with the controlled gas pulsation and used to measure the surface velocities. The respective shock wave-induced displacements of the back and front free surfaces are then calculated. The measured free surface displacements are compared with calibrated thresholds to determine whether a weak bond has been detected or not. Optionally, a ring magnet is aligned exactly under the gas gun nozzle to enable VISAR beam centering.