Affiliations: [a] School of Mechanical and Vehicular Engineering,
Beijing Institute of Technology, Beijing, China | [b] School of Mechanical and Electronical Engineering,
North China University of Technology, Beijing, China | [c] School of Information Science and Technology, Beijing
Institute of Technology, Beijing, China
Abstract: Semisinusoidal loads with constant amplitude or increasing amplitude
were applied on steel specimens separately in earth magnetic field. The testing
results indicated that the variation degree of the magnetic signals was mostly
determined by the amplitude of the applied loads. With the load amplitude
increasing to plastic loading stage, zero-crossing of the
H_{p}(y) distribution curve occurred and stayed at certain
position where the curve has large gradient. The zero-crossing position was
exactly the necking point and unchangeable after unloading, which suggested
that the plastic failures and microdefects can be identified through testing
the H_{p}(y) signals.
Keywords: Cyclic stress, metal magnetic memory effect, magnetic testing, plastic deformation
