Abstract: A coaxial capacitive sensor includes a sensor lubricating oil inlet and a sensor lubricating oil outlet. The sensor lubricating oil inlet and the sensor lubricating oil outlet separately communicate with the interior of the coaxial capacitive sensor. The interior of the coaxial capacitive sensor is provided with a center bearing, electrode support insulating substrates, and electrode plates. The plurality of electrode support insulating substrates and the center bearing divide the interior of the coaxial capacitive sensor into a plurality of detection sub-spaces, and the electrode plates are attached onto the electrode support insulating substrates, respectively. The coaxial capacitive sensor provided by the present invention can be arranged in a lubricating oil pipeline to avoid the influences of environmental factors on the testing results, and can on-line detect the characteristics of the lubricating oil abrasive particles efficiently.

Abstract: A coaxial capacitive sensor includes a sensor lubricating oil inlet and a sensor lubricating oil outlet. The sensor lubricating oil inlet and the sensor lubricating oil outlet separately communicate with the interior of the coaxial capacitive sensor. The interior of the coaxial capacitive sensor is provided with a center bearing, electrode support insulating substrates, and electrode plates. The plurality of electrode support insulating substrates and the center bearing divide the interior of the coaxial capacitive sensor into a plurality of detection sub-spaces, and the electrode plates are attached onto the electrode support insulating substrates, respectively. The coaxial capacitive sensor provided by the present invention can be arranged in a lubricating oil pipeline to avoid the influences of environmental factors on the testing results, and can on-line detect the characteristics of the lubricating oil abrasive particles efficiently.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A networked configuration of structural health monitoring elements. Monitoring elements such as sensors and actuators are configured as a network, with groups of monitoring elements each controlled by a local controller, or cluster controller. A data bus interconnects each cluster controller with a router, forming a networked group of “monitoring clusters” connected to a router. In some embodiments, the router identifies particular clusters, and sends commands to the appropriate cluster controllers, instructing them to carry out the appropriate monitoring operations. In turn, the cluster controllers identify certain ones of their monitoring elements, and direct them to monitor the structure as necessary. Data returned from the monitoring elements is sent to the cluster controllers, which then pass the information to the router. Other embodiments employ multiple sensor groups directly connected to a central controller, perhaps with distributed local control elements. Methods of operation are also disclosed.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Systems and methods for pedestrian impact detection are provided. Piezoelectric sensor elements detect an object impacting a vehicle. The detected signal is attenuated and filtered. The attenuated and filtered signal is analyzed in the frequency domain to determine whether the object which impacted the vehicle is a pedestrian. If the object which impacted the vehicle is a pedestrian, then a pedestrian protection system is deployed.

Abstract: A sensor network is attached to a structure and employed to detect and analyze load changes. The sensor network has transducers, capable of acting as both passive sensors and active actuators, integrated within it. In a passive mode, the transducers detect load changes upon the structure, such as impacts. Upon detection of a load change, the transducers are engaged in an active mode to actively scan the impact area to determine the location and size of any resulting damage region. In this manner, passive and active systems are integrated within a single, convenient layer that possesses the best features of both active systems and passive systems.