This paper summarizes ongoing work on the development of array-based leak location sensors for spacecraft application. The approach uses spatial Fourier transformation of plate wave signals to robustly determine the direction of signal propagation, independent of the effects of dispersive multiple mode signal transport. The robustness of the measurement has been demonstrated, and the measurement has been implemented in a simple low-cost array sensor, using inexpensive electronics and fabrication techniques. Leak location using the sensor has been demonstrated on structural plate specimens containing integral stiffeners. A significant outcome of this demonstration was the observed dependence of signal transmission efficiency on the geometry of integrally machined stiffeners as found in skins of spacecraft structures. In one sample, a tall thin stiffener geometry was found to transmit plate wave signals very efficiently, whereas in a second sample, a stiffener having a square profile, equal in dimension to the plate thickness, was found to significantly diminish transmission. A computational model was used to quantify the observed behavior. Results of the computational model suggest that a lower operating frequency should be used for the second specimen. More generally, the computational model suggests that the operating frequency should be explicitly matched to the transmission characteristics of the stiffener geometry. Ongoing work is modifying the array sensor for lower frequency operation, after which further tests will be conducted.
Array-based acoustic leak location in spacecraft structures
Array basierte akustische Leckortung in Raumfahrtstrukturen
2007
8 Seiten, 7 Bilder, 5 Quellen
Conference paper
Storage medium
English
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