Stress assessment using pulse-excited magnetic Barkhausen noise with high frequency stability and sensitivity

Abstract

Abstract In this paper, a rectangular excitation is employed for nondestructive assessment of compressive applied stress (0-150 MPa) on Q235 steel using magnetic Barkhausen noise (MBN) technique. The response durations almost keep constant due to the variation rate of applied voltage is fixed whatever the excitation frequency is. After eliminating the excitation induced pulse signal, the ring count feature is extracted to measure the applied stress. The traditional features, root mean square (RMS) and skewness, with sine and triangle excitation are compared with the proposed feature. Ring count presents monotonous relations to the applied stress, and is almost impervious to the excitation frequency, especially when the applied stress more than 75 MPa. Although the sensitivity of ring count feature is less than skewness in low-stress loading situation, it provides high sensitivity as well as RMS feature and better frequency stability, which contributes to the actual applications for stress measurement and evaluation based on MBN technique.