In one embodiment, a sensor network is attached to a structure and employed to detect and analyze load changes such as impacts from projectiles. An analyzer coupled to the sensors can determine where on the structure the projectile impacted. Coupled with information on the origin point of the projectile, i.e. where it was fired from, the analyzer can then estimate the trajectory of the projectile. The analyzer can also determine whether the projectile passed through the structure and, if so, can extrapolate the estimated trajectory to determine an estimation of whether the projectile has also impacted an object behind the structure.
F41H 13/00 - Means of attack or defence not otherwise provided for
F41J 5/056 - Switch actuation by hit-generated mechanical vibration of the target body, e.g. using shock or vibration transducers
G01L 5/14 - Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring the force of explosionsApparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring the energy of projectiles
G01L 1/14 - Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
G01L 5/00 - Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
09 - Scientific and electric apparatus and instruments
Goods & Services
structural health monitoring products, namely, sensors, detectors, and downloadable computer software for the evaluation of structural integrity for the automotive, aviation, aerospace, naval, and construction industries
4.
System and method for monitoring the structural health of coupled bearings
Placement of structural health monitoring sensors within a coupled bearing assembly. An exemplary structural health monitoring system comprises first and second bearings configured for rotatable positioning along a structure, and a spacer positioned between the first and second bearings. The first and second bearings are placed against opposing sides of the spacer, and have a preload force engaging the respective first and second bearings against the opposing sides of the spacer. A plurality of sensors are coupled to the spacer so as to be positioned between the spacer and at least one of the first and second bearings, the sensors further coupled to at least one of the first and second bearings so as to be configured to monitor a structural health of the at least one of the first and second bearings.
A structural health monitoring system comprises a first set of sensors operable for coupling to a structure positioned under ground, the first set of sensors further configured to detect an impact upon the structure while the first set of sensors is positioned under the ground; a second set of sensors operable to be positioned on or proximate to a surface of the ground, the second set of sensors further configured to detect an audible event occurring at a distance from the second set of sensors and the structure; and a computer readable memory storing one or more audio signatures that may correspond to the audible event.
A structural health monitoring system comprises: a flexible substrate configured for attachment to a structure, the flexible substrate having a plurality of sensors affixed thereon. The flexible substrate comprises a first portion configured for attachment to the structure, a second portion extending in continuous manner from the first portion, and a third portion extending in continuous manner from the second portion and being configured for attachment to the structure. The second portion includes a first section extending in continuous manner from the first portion, a second section connected between the first section and the third portion and having an edge extending in a direction different from an edge of the first section.
A structural health monitoring apparatus is presented. According to an embodiment, the structural health monitoring apparatus comprises: a plurality of transducers configured for coupling to a structure, the structure comprising an outer structure surrounding and coupled to an inner structure, the transducers further configured for coupling to only the outer structure so as to transmit stress waves through the inner structure, and still further configured to receive the transmitted stress waves from the outer structure after they have passed through the inner structure; and an analyzer configured to detect damage within the inner structure according to the received transmitted stress waves from the outer structure.
G01N 29/48 - Processing the detected response signal by amplitude comparison
G01N 29/265 - Arrangements for orientation or scanning by moving the sensor relative to a stationary material
G01N 29/22 - Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic wavesVisualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object Details
Methods and apparatuses for monitoring a first structure at least partially according to properties of a second structure. One such method comprises determining a first relationship between a first variable and a second variable, wherein the first variable represents sizes of actual damage to the second structure, and the second variable represents sizes of simulated damage on the second structure; determining a second relationship between a third variable and a fourth variable, wherein the third variable represents sizes of simulated damage on the first structure, and the fourth variable represents values of a damage index determined for the simulated damage on the first structure; and determining an estimate of damage to the first structure according to the first and second relationships.
A structural health monitoring system capable of maintaining electrical contact with sensors affixed to a rotating structure. One such structural health monitoring system comprises a rotatable structure, a plurality of sensors each affixed to the rotatable structure, and an interface. The interface has an inner housing and an outer housing, and maintains a plurality of individual electrical connections, each of the individual electrical connections being an electrical connection between one of the sensors and an electrical contact maintained on the outer housing, the electrical connections configured to be maintained during rotation of the structure. The inner housing is affixed to the structure and the outer housing is rotationally coupled to the inner housing, so that the inner housing is free to rotate with respect to the outer housing during rotation of the structure and the sensors, while maintaining the electrical connections.
G01N 29/22 - Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic wavesVisualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object Details
G01N 29/27 - Arrangements for orientation or scanning by moving the material relative to a stationary sensor
10.
System and method for monitoring the structural health of coupled bearings
Placement of structural health monitoring sensors within a coupled bearing assembly. An exemplary structural health monitoring system comprises first and second bearings configured for rotatable positioning along a structure, and a spacer positioned between the first and second bearings. The first and second bearings are placed against opposing sides of the spacer, and have a preload force engaging the respective first and second bearings against the opposing sides of the spacer. A plurality of sensors are coupled to the spacer so as to be positioned between the spacer and at least one of the first and second bearings, the sensors further coupled to at least one of the first and second bearings so as to be configured to monitor a structural health of the at least one of the first and second bearings.
A structural health monitoring system using ASICs for signal transmission, reception, and analysis. Incorporating structural health monitoring functionality into one or more ASICs provides a durable yet small, lightweight, low cost, and portable system that can be deployed and operated in field conditions. Such systems provide significant advantages, especially in applications such as armor structures.
A trigger circuit for use with a structural health monitoring system. To save power, a structural health monitoring system is programmed with a sleep mode and a wake, or operational, mode. In its operational mode, the structural health monitoring system can perform its usual tasks, e.g. monitoring a structure and determining its structural health. In sleep mode, many functions are suspended, so that the system requires less power. The trigger circuit wakes the system when the sensors of the structural health monitoring system emit a sufficiently large signal, i.e. when an event occurs. That is, when not in use, the system enters sleep mode, and when some event occurs (e.g., impact, or some other stresses that are of concern), the trigger circuit alerts the system, prompting it to shift from sleep mode to operational mode and to begin taking/analyzing data.
A structural health monitoring (SHM) system that protects its active and passive components with filter circuits, instead of switches. The active module of the SHM system utilizes a high pass filter, and the passive module of the SHM system utilizes a low pass filter. The active module transmits its interrogating, or excitation, signals at relatively high frequencies that are filtered out by the low pass filter of the passive module, preventing the passive module from sustaining any damage due to the high voltage excitation signals. Meanwhile, the high frequency interrogating signals are passed to the active module's circuitry by its high pass filter, where they can be analyzed accordingly.
G01B 3/44 - Gauges with an open yoke and opposed faces, i.e. calipers, in which the internal distance between the faces is fixed, although it may be preadjustable of limit-gauge type, i.e. "go/no-go" preadjustable for wear or tolerance
A self-sufficient structural health monitoring system that can monitor a structure without need for external power input. Embodiments of the invention provide a structural health monitoring system with a power supply integrated within, so that the system relies on itself for operational power. Systems with such an on-board electrical power source, independent of an external power source (and in particular, independent of the power system(s) of the structure being monitored), are much more self-contained and self-sufficient.
G01B 3/44 - Gauges with an open yoke and opposed faces, i.e. calipers, in which the internal distance between the faces is fixed, although it may be preadjustable of limit-gauge type, i.e. "go/no-go" preadjustable for wear or tolerance
15.
Method and apparatus for estimating damage in a structure
Detecting damage in a structure without comparing sensor signals to a baseline signal. Once a structure is interrogated, a process based on a Gaussian Mixture Model is applied to the resulting data set, resulting in quantities for which Mahalanobis distances and Euclidian distances can be determined. A damage index is then determined based on the calculated Euclidian distance. A high value of this damage index coupled with an abrupt change in Mahalanobis distance has been found to be a reliable indicator of damage. Other embodiments may employ a baseline, but determine damage according to ratios of energy values between current and baseline signals.
G01B 3/44 - Gauges with an open yoke and opposed faces, i.e. calipers, in which the internal distance between the faces is fixed, although it may be preadjustable of limit-gauge type, i.e. "go/no-go" preadjustable for wear or tolerance
16.
Integrated circuit system for controlling structural health monitoring processes and applications therefor
A structural health monitoring system using ASICs for signal transmission, reception, and analysis. Incorporating structural health monitoring functionality into one or more ASICs provides a durable yet small, lightweight, low cost, and portable system that can be deployed and operated in field conditions. Such systems provide significant advantages, especially in applications such as armor structures.
Storage of information, such as baseline information and structure ID, in a memory that is mounted on the structure, rather than inside the diagnosis hardware. This allows for faster and more convenient information retrieval. In particular, this approach allows for a more modular system in which different diagnosis hardware or other analyzers can be simply plugged into a structure's sensor network, whereupon they can quickly download any desired structure-specific information (e.g., baseline information, structure ID, and other useful information) from the on-structure memory.
G06F 19/00 - Digital computing or data processing equipment or methods, specially adapted for specific applications (specially adapted for specific functions G06F 17/00;data processing systems or methods specially adapted for administrative, commercial, financial, managerial, supervisory or forecasting purposes G06Q;healthcare informatics G16H)
18.
Method and apparatus for loosening of fasteners on structures
Methods and apparatuses for detecting fastener loosening. Sensors query a structure at a baseline value of an environment variable, such as temperature, and this baseline signal is stored for later use. Subsequently, users can query the structure remotely and at any time, and the signals from these queries are compared to the stored baseline signal. In some embodiments, an index is calculated, and the system determines that one or more fasteners have come loose if the calculated index exceeds a predetermined threshold value. It is desirable to select a time window within which the query signal is most sensitive to fastener loosening but least sensitive to variations in the environment variable. Accordingly, embodiments of the invention include methods and apparatuses for determining an optimal time window for use in calculating the above described index.
G01N 29/14 - Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic wavesVisualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object using acoustic emission techniques
19.
Method and apparatus for conducting structural health monitoring in a cryogenic, high vibration environment
Sensors affixed to various such structures, where the sensors can withstand, remain affixed, and operate while undergoing both cryogenic temperatures and high vibrations. In particular, piezoelectric single crystal transducers are utilized, and these sensors are coupled to the structure via a low temperature, heat cured epoxy. This allows the transducers to monitor the structure while the engine is operating, even despite the harsh operating conditions. Aspects of the invention thus allow for real time monitoring and analysis of structures that operate in conditions that previously did not permit such analysis. A further aspect of the invention relates to use of piezoelectric single crystal transducers. In particular, use of such transducers allows the same elements to be used as both sensors and actuators.
G01N 29/14 - Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic wavesVisualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object using acoustic emission techniques
20.
Method and apparatus for detecting damage in armor structures
Detection of damage in armor structures, using networks of piezoelectric transducers. In particular, piezoelectric transducers can be placed at various points on the armor structure, effectively creating a number of paths between pairs of transducers. Each of these paths can be queried by transmitting an ultrasonic stress wave from one transducer to the other, and analyzing changes in the stress wave. The signal from the received stress wave can be time gated to remove crosstalk, and the resulting time gated signal can be analyzed for characteristics of damage. For instance, if the time gated signal is sufficiently attenuated, it can be determined that the armor structure has sustained damage to at least that region traversed by this particular path.
A method for automatically creating a probability of detection (POD) curve of an entire network of transducers monitoring and detecting damage in a structure is based on the POD of each of the individual actuator-sensor paths. These individual path PODs may be generated in different ways, such as by experimentation or simulation. This technique makes it possible to create the POD curve of a structural health monitoring (SHM) system for the detection of damages in structures.
A method and system of compensating for environmental effect when detecting signals using a structural health monitoring system includes collecting baseline data signals for one or more values of the environmental effect variable from signals transmitted along selected paths between transducers in an array attached to the structure. A threshold is selected based on the baseline data for determining if the signal is detected. Current data signals are collected and matched to the best fit baseline data. The value of the environmental effect variable is determined on the basis of the matching. A signal is detected according to the selected threshold.
G01D 21/00 - Measuring or testing not otherwise provided for
G01H 17/00 - Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves, not provided for in the other groups of this subclass
G06F 19/00 - Digital computing or data processing equipment or methods, specially adapted for specific applications (specially adapted for specific functions G06F 17/00;data processing systems or methods specially adapted for administrative, commercial, financial, managerial, supervisory or forecasting purposes G06Q;healthcare informatics G16H)
A method of improving damage detection in a structural health monitoring system includes obtaining a baseline set of signals corresponding to a range of values of an environmental effect variable for a plurality of first selected paths between pairs of a plurality of transducers configured in an array attached to a structure. Threshold levels are established for each of the selected paths for determining detection of damage in the structure based on differences in the baseline set of signals for the selected path. A current signal is acquired for each of the selected paths. The plurality of current signals are analyzed based on the threshold levels to detect damage in the structure.
G01R 31/00 - Arrangements for testing electric propertiesArrangements for locating electric faultsArrangements for electrical testing characterised by what is being tested not provided for elsewhere
24.
Transducer array self-diagnostics and self-healing
A method of performing transducer self-diagnostics and self-healing on an array of sensor transducers bonded to a structure for health monitoring includes measuring impedance to detect whether a transducer is missing, or a connection is damaged. Pitch-catch signals generated between one or more pairs of transducers are analyzed for detecting defects according to selected criteria of defect size and location to determine whether the sensors are damaged or partially/fully disbonded. Based on the resulting map of operational transducers, signal transmission paths are added/extended between additional pairs of transducers to maintain inspection coverage of the structure according to the selected criteria.
G01C 25/00 - Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass
G01R 15/00 - Details of measuring arrangements of the types provided for in groups , or
G01R 31/00 - Arrangements for testing electric propertiesArrangements for locating electric faultsArrangements for electrical testing characterised by what is being tested not provided for elsewhere
G01N 29/00 - Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic wavesVisualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
Methods and apparatus for extracting the first arrival wave packet of an acoustic signal in a structural health monitoring (SHM) system include receiving an acoustic signal transmitted between two transducers thereof. Electromagnetic cross-talk is removed from the signal. Signal amplitude threshold values used for picking out the first arrival wave packet are chosen based on signal characteristics or chosen adaptively as the value that leads to the minimum variance of the group velocity estimates of all the actuation-sensing transducer pairs. The group velocity is estimated as the known actuator-sensor distance divided by the propagation time of the first wave packet of which the envelope exceeds a candidate threshold value. The first arrival wave packet is determined as the signal segment where the signal envelope first exceeds the chosen amplitude threshold and the segment length exceeds a specified threshold of time width.
A method for determining optimal locations of a plurality of sensors for damage detection in a structural health monitoring system includes providing a one or more signal performance characteristics, spatial parameters describing a layout of a structure, and generating a layout for the plurality of sensors according to the signal performance characteristics and the spatial parameters. An estimated largest critical damage size that may not be detected by sensors arranged according to the first layout is determined. The layout is edited so as to reduce the estimated largest critical damage size to be less than or equal to a selected maximum size requirement.
G01B 5/28 - Measuring arrangements characterised by the use of mechanical techniques for measuring roughness or irregularity of surfaces
G06F 19/00 - Digital computing or data processing equipment or methods, specially adapted for specific applications (specially adapted for specific functions G06F 17/00;data processing systems or methods specially adapted for administrative, commercial, financial, managerial, supervisory or forecasting purposes G06Q;healthcare informatics G16H)
27.
Detecting damage in metal structures with structural health monitoring systems
G06F 19/00 - Digital computing or data processing equipment or methods, specially adapted for specific applications (specially adapted for specific functions G06F 17/00;data processing systems or methods specially adapted for administrative, commercial, financial, managerial, supervisory or forecasting purposes G06Q;healthcare informatics G16H)
28.
Functional actuator-sensor path optimization in structural health monitoring system
A method for optimizing transducer performance in an array of transducers in a structural health monitoring system includes specifying a plurality of paths between pairs of the transducers on a monitored structure and evaluating the quality of signal transmissions along the paths so as to optimize the gain and frequency operating condition of the transducers.
G01N 9/24 - Investigating density or specific gravity of materialsAnalysing materials by determining density or specific gravity by observing the transmission of wave or particle radiation through the material
29.
Dynamic environmental change compensation of sensor data in structural health monitoring systems
A method for adjusting signal data detected in a structural health monitoring (SHM) system to compensate for the effects of environmental variables acting thereon includes constructing a baseline data space comprised of sets of signal data. Current signal data sets are collected for comparison to the baseline data space. The collected current signal data sets are amended to best match baseline signal data sets in the baseline data space. A set of indices are computed for comparing the amended current signal data set to the baseline signal data sets. A threshold for detection is determined by outlier detection for the computed indices. A signal in the collected signal data set is determined to be detected on the basis of the threshold. A representation of the detected signal strength is provided on the basis of the computed indices.
Predicting the probability of detection of major and minor defects in a structure includes simulating a plurality of N defects at random locations in a region specified by an array of transducers. Defect size is incremented until it intersects one path between two transducers. The defect size is again incremented until it intersects two or more adjacent paths between pairs of transducers. The number of major defects up to a selected size is determined by the total number of single path intersections by defects up to the selected size. The number of minor defects up to a selected size is determined on the basis of the total number of defects intersecting two or more paths up to the selected size. The probability of detection up to a selected size is the cumulative number of major or minor defects up to the selected size normalizing by N.
A method for calculating the probable damage size in a structure includes defining a configuration of an array of transducers mounted on the structure. Any pair of the transducers includes an actuator and a sensor, and each pair defines a propagation path in the structure. All propagation paths that are affected by being touched by a damage of the structure, and all adjacent paths that are untouched and thereby unaffected by the damage, are identified. A range of sizes of the damage is determined, and a probability density of the damage versus damage size is calculated on the basis of the transducer array configuration and the affected and unaffected propagation paths identified. On the basis of the probability density, a most probable damage size is determined, and the probability of the damage being greater or less than the most probable damage size is also determined.
09 - Scientific and electric apparatus and instruments
Goods & Services
Electronic inspection device consisting of thin dielectric film with embedded actuators and sensors, for monitoring structural health of metal, concrete or composite structures
33.
Method and apparatus for reducing crosstalk in a structural health monitoring system
Methods and apparatus for reducing crosstalk in a structural health monitoring system. A pair of actuator input signals are sent to an actuator, each resulting in the transmission of stress waves to a corresponding sensor. The sensor then converts these stress waves to a pair of output signals, each having a crosstalk portion due to electromagnetic interference from the input signals to the actuator, and a stress wave portion corresponding to the stress waves. Various methods of varying the actuator input signals, the input to the actuator, and the output of the sensor result in two output signals that can be combined so as to reduce the crosstalk portions and isolate the stress wave portions. This allows actuators and sensors to be placed sufficiently close together that the stress wave portions of sensor output signals can overlap their crosstalk, without corrupting or otherwise compromising the data contained therein.
Use of a single line for switching multiple monitoring elements on/off, and a single line for sending signals to, or receiving signals from, those elements that are switched on. Monitoring elements each have an associated switching element, and each switching element is connected to a common switching line, or control line. A signal from the control line turns each switch on or off. Each monitoring element is also connected to a single signal line, and only those monitoring elements that are turned on can transmit/receive data signals along this signal line.
A sensor/actuator network configured with a number of electrically-interconnected elements. More specifically, the sensors/actuators are each placed in electrical communication with the same transmission line. Various embodiments of such networks employ sensors/actuators connected in electrical series and in electrical parallel. Networks having these configurations, when placed upon a structure, are capable of detecting and/or transmitting stress waves within the structure so as to detect the presence of an impact, or actively query the structure. Advantageously, as these networks employ a single transmission line, they utilize fewer wires than current sensor/actuator networks, thus making them easier to install and maintain. They can also be configured as flexible layers, allowing for further ease of installation and maintenance.
G01H 11/08 - Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by detecting changes in electric or magnetic properties by electric means using piezoelectric devices
09 - Scientific and electric apparatus and instruments
Goods & Services
Structural Health Monitoring Hardware, namely, scanner for the evaluation of structural integrity applicable in the automotive, aviation, aerospace, naval, energy, and construction industries
