Electromagnetic Ultrasonic Measurement of Bolt Axial Stress Using Barker-Coded Pulse Compression: Modeling and Simulation

Bolts are critical to power systems and pipeline infrastructure, and their axial stress is indicative of joint integrity. To address the low signal-to-noise ratio of echoes in electromagnetic ultrasonic stress measurement of bolts, a finite element analysis model incorporating Barker-coded pulse compression is developed. The analysis examines ultrasonic propagation under varying axial stress states. A 7-bit Barker-coded sinusoid is used as the electromagnetic ultrasonic excitation current, and the echoes are processed by pulse compression. Compared with windowed-sine excitation, the method increases the signal-to-noise ratio by 10 dB and enables rapid, non-contact stress measurement in bolts.