摘要 |
A method and apparatus for measuring stress or strain in a portion of a ferromagnetic member is disclosed in which advantage is taken of the fact that the magnetic properties of a ferromagnetic member change with applied tensile or compressive stress. A magnetic hysteresis loop is measured in a portion of a ferromagnetic member and a model of a magnetic hysteresis loop is fitted to the measured magnetic hysteresis loop by varying at least one stress or strain dependent model variable and the fitted at least one variable is used to determine the stress or strain of the portion. The particular model disclosed is a predator/prey pursuit model wherein the prey is the applied field and the predator is the flux density. |