Ultrasonic Signal Analysis of Solid Propellant Using Hilbert Transform

While the ultrasound technique has demonstrated efficiency in measuring the regression rate of solid propellants, the associated challenge of detecting highly attenuated echoes of ultrasound signals needs to be addressed.The present study constructed an experimental apparatus consisting of an ultrasonic pulser/receiver, a multiplexer, an oscilloscope, and a 0.5 MHz probe, and conducted ultrasound thickness measurements with two types of samples.The Hilbert transform was utilized to obtain the signal envelope and MRL(Mean Resultant Length) by extracting the amplitude and phase characteristics from the measured ultrasonic signals.The signal envelope was found to be unsuitable for low-level echo detection as it significantly decayed along with the attenuating echoes, whereas the MRL enabled the detection of low-level echoes.However, the signal processing method developed in this work exhibited a slight increase in uncertainty for the time-of-flight (TOF) measurement for the highly attenuating samples.Further studies are ongoing to enhance the precision of this ultrasonic technique and apply it to measure the regression rate in solid-fuel ramjets. , , , , . , . , (Signal envelope) MRL(Mean Resultant Length) . /, , 0.5 MHz , . , ,