NONDESTRUCTIVE FATIGUE TEST METHOD FOR FERROMAGNETIC CONSTRUCTION MATERIALS

摘要

A nondestructive test method determines the degree of metalfatigue of test ferromagnetic construction materials by quantifying a changeineffective stress due to aging of the test materials. The disclosed method istomeasure the coercive force Hc and the magnetic susceptibility ~ H of the testmaterials at the field of the coercive force Hc. A current tensile stress.sigma. byputting the coercive force Hc and the magnetic susceptibility ~ H into thefollowing first equation:.sigma. = a (Hc/~H)n.where a and n are known constants determined by the internal structure of thetest materials. A change in current tensile stress of the test materials isdetermined by comparing the effective tensile stress .sigma. of the testmaterialswith the initial tensile stress .sigma.0 of the test materials.