Advanced Signal Analysis and Instrumentation for Barkhausen Stress Measurement in Steels.

摘要

Advanced methods of signal analysis were investigated as a means of improving instrumentation for Barkhausen noise stress measurement. Methods employed included pulse-sorting and pulse-counting, correlation and probability measurements, and spectrum analysis. Specimens of AISI 4340 steel and AISI 4130 steel were studied. It was found that the Barkhausen noise auto-correlation function, amplitude probability distribution, and amplitude probability density correspond closely to the comparable functions obtained from random noise. These statistical functions were found to be independent of magnetization rate and probe liftoff but slightly dependent on stress. Cursory experiments indicated that reducing the detector bandwidth may provide a means of increasing the stress sensitivity of these parameters.