Abstract: A fastener assembly includes a bolt having a head and having a shank. The shank defines threads, the bolt defines a channel which extends circumferentially about the bolt, and the head defines multiple head channels with a first end of each of the multiple head channels in communication with the channel and a second end of each of the multiple head channels in communication with an outside of the head positioned at a top surface of the head. The fastener assembly further includes a sleeve having threads compatible for engaging the threads of the bolt. The sleeve includes a portion of the sleeve including an annealed material and multiple slots defined through the sleeve. With the bolt positioned within the sleeve, each of the multiple slots defined through the sleeve is positioned in communication with the channel.

Abstract: Methods and apparatus for optical imaging and scanning of holes machined, drilled or otherwise formed in a substrate made of composite or metallic material. The method utilizes an optical instrument for imaging and scanning a hole in combination with an image processor configured (e.g., programmed) to post-process the image data to generate one complete planarized image without conical optical distortion. The optical instrument includes an optical microscope with confocal illumination and a conical mirror axially positioned to produce a full 360-degree sub-image with conical distortion. In the post-processing step, a mathematical transformation in the form of computer-executable code is used to transform the raw conical sub-images to planar sub-images. The planarized sub-images may be stitched together to form a complete planarized image of the hole.

Abstract: A plurality of plate pairs that includes at least three plate pairs are positioned over a surface of the composite object. A resistance of a plurality of plies in the composite object is measured in at least three different fiber orientations. Each of the at least three different fiber orientations is measured via a corresponding one of the at least three plate pairs.

Abstract: A neuromorphic architecture is formed from a laminate of non-woven carbon fiber reinforced polymer layers arranged in a plurality of different directions. A plurality of distributed nodes are formed through the laminate via transverse voids, and an encapsulant encapsulates an electrochemical fluid or gel such that the electrochemical fluid or gel may flow within the nodes and around the laminate. Electrical current flowing through the architecture creates reversible metal deposits at various nodes, depending on the path developed through the architecture, with a complexity sufficient for neuromorphic processing, and providing a writable and erasable memory. A neuromorphic actuator may be formed by combining shape memory materials with such a neuromorphic architecture, which may provide desired surface contours and/or actuations based on current in the neuromorphic architecture.

Abstract: Methods and apparatus for optical imaging and scanning of holes machined, drilled or otherwise formed in a substrate made of composite or metallic material. The method utilizes an optical instrument for imaging and scanning a hole in combination with an image processor configured (e.g., programmed) to post-process the image data to generate one complete planarized image without conical optical distortion. The optical instrument includes an optical microscope with confocal illumination and a conical mirror axially positioned to produce a full 360-degree sub-image with conical distortion. In the post-processing step, a mathematical transformation in the form of computer-executable code is used to transform the raw conical sub-images to planar sub-images. The planarized sub-images may be stitched together to form a complete planarized image of the hole.

Abstract: A conductive fastening system, a fastened assembly, and a method of fastening an assembly composed of layers of carbon fiber reinforced plastic (“CFRP”) and/or metallic material includes fasteners with an electrically conductive coating and electrically conductive gap filler materials between the fasteners and sidewalls of holes formed through the layers of the assembly. The sidewalls of the holes are coated with the electrically conductive gap filler material by abrading, injection or spraying. The fasteners with the electrically conductive coating are inserted through the holes. The conductive coating on the fasteners and electrically conductive gap filler material work together to enhance electrical conductivity between the fastener and assembly. The conductive coating also acts as a lubricant to reduce the amount of force required to insert the fastener into the hole thereby reducing damage to the assembly.

Abstract: A fastener assembly includes a bolt having a head and having a shank. The shank defines threads, the bolt defines a channel which extends circumferentially about the bolt, and the head defines multiple head channels with a first end of each of the multiple head channels in communication with the channel and a second end of each of the multiple head channels in communication with an outside of the head positioned at a top surface of the head. The fastener assembly further includes a sleeve having threads compatible for engaging the threads of the bolt. The sleeve includes a portion of the sleeve including an annealed material and multiple slots defined through the sleeve. With the bolt positioned within the sleeve, each of the multiple slots defined through the sleeve is positioned in communication with the channel.

Abstract: A plurality of plate pairs that includes at least three plate pairs are positioned over a surface of the composite object. A resistance of a plurality of plies in the composite object is measured in at least three different fiber orientations. Each of the at least three different fiber orientations is measured via a corresponding one of the at least three plate pairs.

Abstract: A method for applying a coating on a surface of a lamination of plies of fiber-reinforced plastic material. The surface of the lamination includes exposed ends of reinforcement fibers. The method includes selecting an electrically conductive material that is abradable in a solid state by rubbing against the surface of the lamination having exposed ends of reinforcement fibers, and rubbing the electrically conductive material against the surface of the lamination to cause particles of electrically conductive material to be abraded and deposited on the surface of the lamination.

Abstract: A protective layer, a cell and a method provide radiation shielding. The cell and the protective layer formed of a plurality of cells provide radiation shielding, such as from protons and alpha particles having dangerously high energy levels, while being more lightweight than a conventional bulk HDPE protective layer. In the context of a protective layer, the protective layer includes a plurality of cells positioned proximate one another. The plurality of cells include at least a first cell. The first cell includes a cell body formed of an insulative material and extends between opposed first and second ends. The first cell also includes a conductive spherical portion proximate the first end of the cell body and an electrode disposed interior of the conductive spherical portion.

Abstract: The present disclosure relates systems and methods for treating various materials, such as carbon fiber reinforced polymer (CFRP), with a Joule heating process so as to reduce or eliminate a risk of sparks or explosion due to lightning strikes. The disclosure also relates to an aircraft component with structures that have undergone a Joule heating process by way of the systems and methods described herein. An example method includes providing an electrode array having a first and second electrode set. Each of the electrode sets includes one or more disk-shaped electrodes that are arranged in an interdigitated, concentric stack about a central axis. The method also includes causing the electrode array to contact a conductive material. The method additionally includes causing a current source to provide electrical current through the first electrode set and the second electrode set so as to heat at least a portion of a conductive material.

Abstract: A method including receiving a joint parameter for a joint between at least two composite structural components, a ply stackup for each of the at least two composite structural components and an electromagnetic effect parameter in a controller, iteratively processing with the controller, the joint parameter and the ply stackup and outputting an optimized joint parameter based on at least a convergence of an electromagnetic effect resistance of the joint and the at least two composite structural components, and changing, with the controller, a value of one or more of the joint parameters and the ply stackup during the iterative processing to reach the convergence of the electromagnetic effect resistance.

Abstract: Methods and apparatus for optical imaging and scanning of holes machined, drilled or otherwise formed in a substrate made of composite or metallic material. The method utilizes an optical instrument for imaging and scanning a hole in combination with an image processor configured (e.g., programmed) to post-process the image data to generate one complete planarized image without conical optical distortion. The optical instrument includes an optical microscope with confocal illumination and a conical mirror axially positioned to produce a full 360-degree sub-image with conical distortion. In the post-processing step, a mathematical transformation in the form of computer-executable code is used to transform the raw conical sub-images to planar sub-images. The planarized sub-images may be stitched together to form a complete planarized image of the hole.

Abstract: A differential capacitive probe for measuring contact resistance, the differential capacitive probe including a frame, an end effector extending from the frame, a first capacitive pad coupled to the frame so as to at least partially circumscribe the end effector, and a second capacitive pad coupled to the frame so as to be radially spaced, relative to the end effector, from the first capacitive pad and to at least partially circumscribe the end effector, wherein a contact surface area of the first capacitive pad is substantially the same as another contact surface of the second capacitive pad.

Abstract: A fastening device for coupling an assembly includes a fastener comprising a head, a threaded portion, and a shank extending between the head and the threaded portion. The fastening device also includes a coating formed around the fastener, wherein the coating is electrically conductive and comprises a varying thickness along the shank.

Abstract: There is provided an LDE testing system. The system has a test chamber, a test article, and a capacitor to inject current into the test article, to create a spark, emitting a spark spectral signature, and having a spark light intensity. The system has a digitally-controlled reference light source operable to emit a reference light source spectral signature simulating an observed spark spectral signature of sparking in tested test articles, and having a reference light source light intensity equivalent to an observed spark light intensity. The system has a camera to capture an image of the spark spectral signature, spark light intensity, reference light source spectral signature, and reference light source light intensity, a controller to digitally control the digitally-controlled reference light source, and a computer system to receive the image from the camera, and determine a passing or failing result of an LDE testing criteria for the test article.

Abstract: A method for measuring a contact resistance at an interface of an electrically conductive coating and a cross-ply surface of a composite layer having electrically conductive fibers. The method includes: placing a dielectric coating of a sensing pad in contact with the composite layer or with the electrically conductive coating on the cross-ply surface of the composite layer; electrically connecting first and second input terminals of a comparator to the sensing pad and to one side of a capacitor respectively; electrically connecting another side of the capacitor to a fixed resistance; electrically connecting the fixed resistance to an electrically conductive body inserted in a hole in the composite layer; supplying an alternating current to the electrically conductive body and to the fixed resistance; and outputting a characteristic voltage signal if an amplitude of the input signal at the first input terminal is at least equal to an amplitude of the input signal at the second input terminal.

Abstract: A conductive fastening system, a fastened assembly, and a method of fastening an assembly composed of layers of carbon fiber reinforced plastic (“CFRP”) and/or metallic material includes fasteners with an electrically conductive coating and electrically conductive gap filler materials between the fasteners and sidewalls of holes formed through the layers of the assembly. The sidewalls of the holes are coated with the electrically conductive gap filler material by abrading, injection or spraying. The fasteners with the electrically conductive coating are inserted through the holes. The conductive coating on the fasteners and electrically conductive gap filler material work together to enhance electrical conductivity between the fastener and assembly. The conductive coating also acts as a lubricant to reduce the amount of force required to insert the fastener into the hole thereby reducing damage to the assembly.

Abstract: A differential capacitive probe for measuring contact resistance, the differential capacitive probe including a frame, an end effector extending from the frame, a first capacitive pad coupled to the frame so as to at least partially circumscribe the end effector, and a second capacitive pad coupled to the frame so as to be radially spaced, relative to the end effector, from the first capacitive pad and to at least partially circumscribe the end effector, wherein a contact surface area of the first capacitive pad is substantially the same as another contact surface of the second capacitive pad.

Abstract: A conductive fastener system for connecting a composite structure to a support structure includes a composite structure hole that extends through the composite structure and shares a common axis with a support structure hole that extends at least partially through the support structure. A fastener comprising a shank having an outer surface passes through the composite structure hole and at least partially through the support structure hole and provides an annular space between the outer surface of the shank and the inner surface of the composite structure hole. The annular space is filled with a conductive paste that comprises conductive particles suspended in a bonding agent.