Ultrasonic guided wave sensors

For the ultrasonic guided waves, RTD, thermocouple, and FBG measurement corrcepts the ideal sensor element placement would have been directly in the gas stream. This would have provided the fastest response time, but it also presents the most engineering challenges. An in-stream attachment concept is illustrated in Figure 9-47. Since the sensor wires or waveguide break the pressure boundary, the entry point would be closed by a refractory llnerfcap that would not allow the gas to leak out of the pipe or allow any material to enter the coolant,... 

Yu L, Giurgiutiu V. In situ 2-D piezoelectric wafer active sensors arrays for guided wave damage detection. Ultrasonics 2008 48(2) 117—34. http //dx.doi.0rg/lO.lOl6/ j.ultras.2007.10.008. 

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