Materials, Methods & Technologies, Volume 16, 2022

Abstract: This paper deals with the statistical evaluation of the variation of amplitudes measured on ultrasonic transducers, which were parabolic displaced. The reflecting surface was used metal plate of dimensions 245x220x1 millimetres. The distance of the ultrasonic transmitter from the reflection normal was set conically to 190 mm. The distance of the ultrasonic of the transducers from the reflection normal was 900 mm. At the significance level of α = 0.05, it was shown that there is a statistically significant decrease in absolute amplitude with increasing angle of the reflection normal on the ultrasound transducers. The critical angle was set to be 30°, which supports the chosen angular limit at the -6 dB attenuation band for the ultrasonic transducer used. Significant differences in the amplitudes of the ultrasonic signals give an indication of the direction of tilt of the reflecting surface. The statistically observed differences between the ultrasonic signal amplitudes are more indicative than the attenuation criteria of -3 dB and -6 dB, respectively. The mean values of the signal amplitudes were determined by arithmetic averaging over four repetitions of the experiment. The normality of the distribution of the detected signal amplitudes was verified at a significance level of α = 0.05 by the Shapiro-Wilk test.