Abstract: A system for detecting damage in an aircraft structure includes an aircraft structure and a structural health monitoring (SHM) system for monitoring the health of the aircraft structure independent of temperature. The SHM system includes an actuator bonded to the aircraft structure and configured to generate a reference vibration signal having a reference amplitude that propagates through the aircraft structure at a first time, and generate a comparison vibration signal having a comparison amplitude that propagates through the aircraft structure at a second time after the first time. The comparison amplitude represents damage incurred by the aircraft structure between the first time and the second time. The SHM system includes a sensor bonded to the aircraft structure that receives the reference vibration signal and the comparison vibration signal, and a processor configured to compute a gain damage index as a function of the reference amplitude divided by the comparison amplitude.

Abstract: A system for detecting damage in an aircraft structure includes an aircraft structure and a structural health monitoring (SHM) system for monitoring the health of the aircraft structure independent of temperature. The SHM system includes an actuator bonded to the aircraft structure and configured to generate a reference vibration signal having a reference amplitude that propagates through the aircraft structure at a first time, and generate a comparison vibration signal having a comparison amplitude that propagates through the aircraft structure at a second time after the first time. The comparison amplitude represents damage incurred by the aircraft structure between the first time and the second time. The SHM system includes a sensor bonded to the aircraft structure that receives the reference vibration signal and the comparison vibration signal, and a processor configured to compute a gain damage index as a function of the reference amplitude divided by the comparison amplitude.

Abstract: A system is provided for structural load assessment of an aircraft. An approximator may receive parameters related to a ground or flight event and calculate the resulting response load on the aircraft using a machine learning algorithm and a structural dynamics model of the aircraft. An analysis engine may compare the calculated response load to a corresponding design load for determining the structural severity of the ground or flight event on the aircraft. A maintenance engine may then automatically perform or trigger a maintenance activity for the aircraft in instances in which the structural severity of the ground or flight event causes a limit exceedance state of the aircraft or at least one structural element thereof.

Abstract: Described herein is an apparatus for detecting damage in a structure that includes a plurality of first piezoelectric sensing elements arranged in a generally circular shape. The apparatus also includes an annular-shaped second piezoelectric sensing element positioned adjacent the plurality of first piezoelectric sensing elements. One of the plurality of first piezoelectric sensing elements or the annular-shaped second piezoelectric sensing element generates a wave through the structure and other of the plurality of first piezoelectric sensing elements or the annular-shaped second piezoelectric sensing element senses the wave after passing through the structure.

Abstract: Described herein is an apparatus for detecting damage in a structure that includes a plurality of first piezoelectric sensing elements arranged in a generally circular shape. The apparatus also includes an annular-shaped second piezoelectric sensing element positioned adjacent the plurality of first piezoelectric sensing elements. One of the plurality of first piezoelectric sensing elements or the annular-shaped second piezoelectric sensing element generates a wave through the structure and other of the plurality of first piezoelectric sensing elements or the annular-shaped second piezoelectric sensing element senses the wave after passing through the structure.

Abstract: A method for compensating for environment induced variations in structural health monitoring data is described. The method includes imparting a vibration onto a structure first location, the structure at a first temperature, receiving a comparison signal resulting from the vibration at a second location, accessing data representing a reference signal previously received at the second location, based on vibration at the first location, the reference signal received when the structure was at a second temperature, dividing the signals across multiple time windows, performing a cross correlation between the signals in each window to maximally correlate the signals within each window, performing a weighted regression on time to estimate time shift, the weights based on reference signal energy in each window, to determine a relationship between time and time shift, and using the relationship between time and time shift of the comparison signal to reduce the effects of environment on the comparison signal.

Abstract: The invention relates to systems and methods which may be used to determine when an uncured composite part is ready to be cured. In one embodiment, a system under the invention may comprise an infrared camera adapted to take infrared images of an uncured composite part, a heating device adapted to heat an uncured composite part, an image capture device adapted to capture infrared images taken by the infrared camera, and a computer adapted to analyze infrared images taken by the infrared camera in order to evaluate temperatures of an uncured composite part. The infrared images may be used to determine that the composite part is substantially covered, and/or completely covered, with resin and ready to be cured.

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 method for compensating for environment induced variations in structural health monitoring data is described. The method includes imparting a vibration onto a structure first location, the structure at a first temperature, receiving a comparison signal resulting from the vibration at a second location, accessing data representing a reference signal previously received at the second location, based on vibration at the first location, the reference signal received when the structure was at a second temperature, dividing the signals across multiple time windows, performing a cross correlation between the signals in each window to maximally correlate the signals within each window, performing a weighted regression on time to estimate time shift, the weights based on reference signal energy in each window, to determine a relationship between time and time shift, and using the relationship between time and time shift of the comparison signal to reduce the effects of environment on the comparison signal.

Abstract: A method, apparatus, and computer usable program code for identifying change indices for a structure. In one advantageous embodiment a method receives a response signal in response to a transmission of an interrogation signal into the structure. The response signal is decomposed into a first plurality of modes. The first plurality of modes is compared to a second plurality of modes for a comparison signal to form a comparison. A change index is assigned to the response signal using the comparison.

Abstract: A method for determining the health of a structural element. The method includes providing a plurality of transducer elements arranged and disposed to permit measurement of vibration generated by at least one of the transducer elements at one or more of the other transducers elements. Vibration is induced with at least one transducer element. Vibration is measured at least one other transducer element, where the measured vibration corresponding to a vibratory path. At least one damage index value is calculated for each vibratory path in response to the measured vibration. At least one damage image is generated in response to the damage index value. The damage image assigns damage index values to each vibratory path. A damage location is determined from the damage image.

Abstract: The invention relates to systems and methods which may be used to determine when an uncured composite part is ready to be cured. In one embodiment, a system under the invention may comprise an infrared camera adapted to take infrared images of an uncured composite part, a heating device adapted to heat an uncured composite part, an image capture device adapted to capture infrared images taken by the infrared camera, and a computer adapted to analyze infrared images taken by the infrared camera in order to evaluate temperatures of an uncured composite part. The infrared images may be used to determine that the composite part is substantially covered, and/or completely covered, with resin and ready to be cured.

Abstract: The invention relates to systems and methods which may be used to determine when an uncured composite part is ready to be cured. In one embodiment, a system under the invention may comprise an infrared camera adapted to take infrared images of an uncured composite part, a heating device adapted to heat an uncured composite part, an image capture device adapted to capture infrared images taken by the infrared camera, and a computer adapted to analyze infrared images taken by the infrared camera in order to evaluate temperatures of an uncured composite part. The infrared images may be used to determine that the composite part is substantially covered, and/or completely covered, with resin and ready to be cured.

Abstract: A method for creating at least one input parameter for an algorithmic system to evaluate damage in a structure may include: (a) Determining a plurality of damage index factors using first signal information relating to a first signal transmitted through the structure before the damage is imposed, and second signal information relating to a second signal transmitted through the structure after the damage is imposed. (b) determining a plurality of condensed damage index factors using the plurality of damage index factors. (c) Correlating selected of the condensed damage index factors with selected measured dimensions relating to the damage to determine a correlation index for selected combinations of the condensed damage index factors and the dimensions. (d) Selecting the at least one input parameter from among the selected condensed damage index factors having a correlation index meeting at least one predetermined criterion.

Abstract: A method, apparatus, and computer usable program code for identifying change indices for a structure. In one advantageous embodiment a method receives a response signal in response to a transmission of an interrogation signal into the structure. The response signal is decomposed into a first plurality of modes. The first plurality of modes is compared to a second plurality of modes for a comparison signal to form a comparison. A change index is assigned to the response signal using the comparison.

Abstract: A method for determining the health of a structural element. The method includes providing a plurality of transducer elements arranged and disposed to permit measurement of vibration generated by at least one of the transducer elements at one or more of the other transducers elements. Vibration is induced with at least one transducer element. Vibration is measured at least one other transducer element, where the measured vibration corresponding to a vibratory path. At least one damage index value is calculated for each vibratory path in response to the measured vibration. At least one damage image is generated in response to the damage index value. The damage image assigns damage index values to each vibratory path. A damage location is determined from the damage image.

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 method for creating at least one input parameter for an algorithmic system to evaluate damage in a structure may include: (a) Determining a plurality of damage index factors using first signal information relating to a first signal transmitted through the structure before the damage is imposed, and second signal information relating to a second signal transmitted through the structure after the damage is imposed. (b) determining a plurality of condensed damage index factors using the plurality of damage index factors. (c) Correlating selected of the condensed damage index factors with selected measured dimensions relating to the damage to determine a correlation index for selected combinations of the condensed damage index factors and the dimensions. (d) Selecting the at least one input parameter from among the selected condensed damage index factors having a correlation index meeting at least one predetermined criterion.

Abstract: A method, a computer-readable medium, and a system for tuning a cost function to control an operational plant are provided. A plurality of cost function parameters is selected. Predicted future states generated by the neural network model are selectively incorporated into the cost function, and an input weight is applied to a control input signal. A series of known signals are iteratively applied as control input inputs, and the cost output is calculated. A phase is taken of the control and plant outputs in response to each of the known signals and combined, thereby allowing effective combinations of the cost function parameters, the input weight, and the predicted future states to be identified.

Abstract: A method for monitoring damage to a structure having an actuator and a sensor. The method includes exciting the actuator across a predetermined frequency range to excite the structure, measuring a vibrational characteristic of the structure across the predetermined frequency range in response to the excitation of the actuator using the sensor, calculating a transfer function for the actuator and the sensor using the measured vibrational characteristic, determining a change in the vibrational characteristic across the predetermined frequency range using the transfer function, and analyzing the determined change in the vibrational characteristic across the predetermined frequency range to facilitate determining whether the structure is damaged.