Method and Apparatus for Detection and Characterization of Mechanical Damage

摘要

Yield stress is an important indicator of the strength of a component such as a pipe section. A method and apparatus for measuring yield stress of components made from magnetic materials is provided. The magnetic permeability of the material is recorded at multiple stress levels below yield establishing a permeability-stress relationship. The yield stress is then estimated as a function of the recorded permeability-stress relationship. The permeability stress relationship may be non-linear for a range of stress levels, achieving a peak permeability response for a stress below yield. The yield stress may be estimated as a multiple of the stress at which the peak permeability response is recorded.

主权项

1. A method for estimating yield stress of a component, the method comprising:
positioning a sensor proximal to the component; measuring, with at least an impedance instrument and the sensor, magnetic permeability of the component at a plurality of stress levels; and estimating the yield stress as a function of the magnetic permeabilities and the corresponding stress levels.