Surface roughness evaluation via ultrasonic scanning

摘要

Despite extensive applications of ultrasonic waves to variousnnondestructive testing and evaluation of materials, scattering ofnfocused ultrasonic waves due to surface roughness has not been fullyninvestigated. This paper presents an analytical and experimentalnevaluation of surface roughness measurement using focused ultrasonicnbeams. The characteristics of focused ultrasonic waves are analyzed bynusing the impulse response method with a sine-modulated Gaussian pulsenas source. First, the beam profile in the focal plane of the focusednultrasonic transducer is analyzed both numerically and experimentally.nSecond, peak amplitude distribution and reflected waveforms from a flatnsurface with various incident angles are analytically generated andncompared with experimental results. Then, the peak amplitudes of thenultrasonic waves reflected from cusped surfaces which are easily foundnamong machined surfaces are analyzed and compared with experimental datanfor the first time. The analysis shows good agreement between analyticalnand experimental results. The excellent correlation between thenmeasurements using a profilometer and the proposed ultrasonic systemndemonstrates a good potential for surface roughness measurement bynultrasonic sensing