Abstract: A method of thermographic nondestructive evaluation may include heating a portion of a surface of an object from a first surface temperature to a second surface temperature that is greater than the first surface temperature, collecting a plurality of thermal images of the portion of the surface of the object, detecting the sound zone of the portion of the surface of the object, determining a characteristic time corresponding to a time after the heating of the portion of the surface of the object wherein the sound zone of the surface of the object approaches a steady state temperature, normalizing temperature data of the plurality of thermal images with respect to the characteristic time and the steady state temperature, and detecting the defect zone based on differences between normalized temperature data of pixels of the defect zone and normalized temperature data of pixels of the sound.

Abstract: A method of thermographic nondestructive evaluation may include heating a portion of a surface of an object from a first surface temperature to a second surface temperature that is greater than the first surface temperature, collecting a plurality of thermal images of the portion of the surface of the object, detecting the sound zone of the portion of the surface of the object, determining a characteristic time corresponding to a time after the heating of the portion of the surface of the object wherein the sound zone of the surface of the object approaches a steady state temperature, normalizing temperature data of the plurality of thermal images with respect to the characteristic time and the steady state temperature, and detecting the defect zone based on differences between normalized temperature data of pixels of the defect zone and normalized temperature data of pixels of the sound.

Abstract: A sensor array for non-destructively monitoring a structure to detect a critical structural event. The sensor array includes at least one discrete AE sensor node for producing an electrical signal in response to a structural event and at least one shear wave sensor assembly. The shear wave sensor assembly includes at least one shear wave sensor. A gate module is connected to the at least one discrete AE sensor node and to the at least one shear wave sensor assembly, whereby the gate module is adapted to pass through the electrical signal from the at least one discrete AE sensor node in response to a pre-determined signal from the at least one shear wave sensor assembly. The sensor array may further include a signal processing module for receiving and processing the discrete AE sensor output signal. In addition, a data collection system may be located downstream of the signal processing module.

Abstract: Sensor assemblies for non-destructively monitoring a structure to detect a structural event include a plurality of sensor nodes configured to provide at least one sensor signal responsive to a structural event. A signal analyzer is configured to compare the sensor signal to a reference database of signal characteristics corresponding to respective structural events.

Abstract: An apparatus and method for forming a densified carbon-carbon composite. The apparatus includes: a green part molding station for forming a green part; a carbonization station for carbonizing the green part; and an impregnation station for impregnating the carbonized part with a substantially curing by-product free, high carbon yield resin. The impregnation station includes a mold forming a sealed enclosure configured in the shape of the carbonized part for receiving the carbonized part and a vacuum source for evacuating the mold. At least one resin injection port is in the mold and a supply of substantially curing by-product free, high carbon yield resin is connected to the resin injection port for injection into the mold. In the preferred embodiment, the substantially curing by-product free, high carbon yield resin is a cyanate ester having a viscosity of less than about 100 cps at 250° F. and a carbon yield value of greater than about 60 wt. %.

Abstract: A sensor array for non-destructively monitoring a structure to detect a critical structural event. The sensor array includes a plurality of discrete sensor nodes, each of the discrete sensor nodes producing an electrical signal in response to a structural event. A signal adder is electrically connected to the plurality of discrete sensor nodes for receiving and combining the electrical signal from each of the discrete sensor nodes to form a single sensor array output signal. A signal processing module then receives and processes the single sensor output signal. In the preferred embodiment, the signal processing module uses the time interval between the electrical signals from each of the discrete sensor nodes formed into a single sensor array output signal to calculate the location of the critical structural event. Also, in the preferred embodiment, a data collection system is located downstream of the sensor processing module.

Abstract: A sensor array for nondestructively monitoring a structure to detect a critical event. The sensor array includes a plurality of discrete sensor nodes, each of the discrete sensor nodes producing an electrical signal in response to a structural event. In the preferred embodiment, the sensor nodes include a plurality of piezoceramic fibers arranged in a planar array in which the fibers are aligned substantially parallel to each other, each of the fibers having a plurality of polarized regions that are substantially oriented according to their polarity in either a series, parallel, or combined arrangement of series and parallel orientations, and an electrical interface connecting the plurality of polarized regions of each fiber in series with one another. A signal adder receives and combines the electrical signals from each of the discrete sensor nodes to form a single sensor array output signal.

Abstract: An apparatus and method for forming a densified carbon-carbon composite. The apparatus includes: a green part molding station for forming a green part; a carbonization station for carbonizing the green part; and an impregnation station for impregnating the carbonized part with a substantially curing by-product free, high carbon yield resin. The impregnation station includes a mold forming a sealed enclosure configured in the shape of the carbonized part for receiving the carbonized part and a vacuum source for evacuating the mold. At least one resin injection port is in the mold and a supply of substantially curing by-product free, high carbon yield resin is connected to the resin injection port for injection into the mold. In the preferred embodiment, the substantially curing by-product free, high carbon yield resin is a cyanate ester having a viscosity of less than about 100 cps at 250° F. and a carbon yield value of greater than about 60 wt. %.