Non-contact Stress Measurement of Rail Steel Using a Magnetic Anisotropy Sensor

The Magnetic Anisotropy Sensors (MAS) is based on the fact that when stress is applied, the magnetic anisotropy of steel materials changes. MAS employs a small, light probe and is capable of non-contact stress measurement. This paper describes experimental results for non-contact stress measurements of rail steel. A specimen was cut from an actual 60 kg steel rail, and tensile and compressive stresses were applied using a fatigue testing machine. Good linearity of the MAS output voltage to the applied stress was observed over tensile stresses between 0 and 160 MPa when demagnetization was employed.