Abstract: A system for monitoring the structural condition of a helicopter rotor assembly component includes a piezoelectric sensor. Acoustic emission signal techniques allow for recognizing the relatively high frequency stress waves associated with the propagation of cracks or defects in a rotor assembly component. A signal conditioner processes the sensor signal and provides an output signal that includes at least one characteristic that is indicative of the content of the sensor signal and, therefore, the structural condition of the item of interest. A signal analyzer utilizes the output signal from the signal processor to determine the structural condition of the component.

Abstract: A system for monitoring the structural condition of a helicopter rotor assembly component includes a piezoelectric sensor. Acoustic emission signal techniques allow for recognizing the relatively high frequency stress waves associated with the propagation of cracks or defects in a rotor assembly component. A signal conditioner processes the sensor signal and provides an output signal that includes at least one characteristic that is indicative of the content of the sensor signal and, therefore, the structural condition of the item of interest. A signal analyzer utilizes the output signal from the signal processor to determine the structural condition of the component.

Abstract: A bearing assembly monitoring system provides continuous, real time monitoring of the operating condition of a powertrain support bearing assembly and real time alarm signals indicative of degradation and/or impending catastrophic failure thereof. One embodiment of the monitoring system includes a vibration sensing device, first and second primary temperature sensing devices, an ambient temperature sensing device, vibration and temperature signal processing subcircuits, and an alarm subsystem. The vibration sensing device monitors complex vibration signals emanating from the bearing assembly and provides signals corresponding thereto. The vibration signal processing circuit filters such complex vibration signals to provide a predetermined bandwidth thereof that are converted to stabilized DC voltage signals which are compared to reference voltages corresponding to higher than normal and excessive vibration levels. Exceedance of such reference voltages generates a corresponding vibration alarm signal.

Abstract: A method and apparatus are described for performing X-ray fluorescence analysis where the physical relationship between the source/detector and the object being examined is not controlled. This technique and apparatus is particularly advantageous in performing an in situ analysis of the concentration of one or more elements present in a matrix of a material such as rock. In accordance with this aspect of our invention, such a mineral assay is performed by drilling a borehole into the matrix, inserting into the borehole a probe containing a suitable XRF source/detector, irradiating the matrix, detecting the spectrum of radiation that is produced and analyzing this spectrum.