Time Domain Analysis of Acoustic Emission Signal for Internal Surface Roughness Classification

Abstract

This paper describes the acoustic emission approach for internal surface roughness classification. Rough internal surface can be related to corrosion that usually occurred inside pipe. Two flow rates with different Reynolds number value are introduced in a pipe (smooth and rough internal surface) obstructed using normally available components (e.g.: valve). The time domain parameter of Acoustic Emission signals; peak amplitude and Root Mean Square (R.M.S) amplitude, at suitable location from the obstruction are obtained. Crest factor, C, which is defined as peak to RMS amplitude ratio was calculated in smooth pipe measurement compared to the crest factor in rough surface pipe measurement. It was observed that, at high flow rate measurement, crest factor value obtained can be used to successfully discriminate between rough and smooth internal surface roughness. For smooth internal surface pipe, the Crest Factor value is above than 4.0 at flow with Reynolds Number value above 40,000. Meanwhile for the C value below than 4.0, it can be classified as rough internal surface pipe.