Nondestructive measurement of stress in ferromagnetic steels using harmonic analysis of induced voltage

Microstructure and Stress Dependence of the Magnetic Properties of Steels

“…An alternative method of evaluating stress is to measure the third harmonic amplitude of the magnetisation under a sinusoidally varying nield. This technique has been used by Burkhardt and Kwun [28].…”

Application of the Nonlinear Harmonics Method to Continuous Measurement of Stress in Railroad Rail

“…are the amplitudes of the third harmonic with the magnetic field applied parallel and perpendicular to the stress direction, respectively. For materials with positive magnetostriction, Apara11e1 increases with tension and decreases with compression; Aperp exhibits the opposite behavior [11,15]. In the absence of stress, S is approximately zero, even if the material properties vary [15].…”

“…For materials with positive magnetostriction, Apara11e1 increases with tension and decreases with compression; Aperp exhibits the opposite behavior [11,15]. In the absence of stress, S is approximately zero, even if the material properties vary [15]. S becomes positive with tension and negative with compression.…”

Measurement of Longitudinal Stress in Railroad Rail Under Field Conditions Using Nonlinear Harmonics

“…For structural steels with positive magnetostriction [4], the harmonic amplitude increases with increasing tension and decreases with increasing compression when the applied magnetic field is parallel to the stress, as illustrated in Fig. 1.…”

“…With the nonlinear harmonics (NLH) technique for stress measurement [4], a sinusoidal magnetic field, H, of a fixed frequency, f, is applied to a ferromagnetic material. The harmonic frequencies, typically the third harmonic, of the applied field frequency are then detected and related to stress.…”