Affiliations: [a] School of Mathematics and Physics, University of
Science and Technology Beijing, Beijing, China | [b] Division of Vehicle Dynamics and Control, Harbin
Institute of Technology, Harbin, Heilongjiang, China | [c] Beijing Institute of Astronautics System Engineering,
Beijing, China
Correspondence:
[*]
Corresponding author: Ming-Xiu Xu, School of Mathematics and
Physics, University of Science and Technology Beijing, Beijing 100083, China.
Tel.: +86 159 107 989 66; E-mail: xmxyippee@126.com
Abstract: In metal magnetic memory (MMM) detection, the Jiles-Atherton model
describes material magnetization caused by the geomagnetic field and cyclic
stress. However, characterization of the effects of fatigue damage on
magnetization remains an issue. In this paper, an expression for magnetization
intensity M_{0} related to dislocation and plastic strain
amplitude ε_{p} was incorporated into a modified
Jiles-Atherton model. To validate the M_{0} expression,
standard tensile fatigue tests were performed. Results indicate that the domain
wall pinning parameter k_{1} in M_{0}
is linear in both dislocation density ρ and average dislocations slippage
distance �λ, as is also the shear plastic strain amplitude in the
stress control fatigue. The stress amplitude in strain control fatigue however
is linear with respect to ρ^{1/2} . Therefore, M_{0} can be expressed as a function of stress and
ε_{p} (or �λ and stress amplitude).
Experiments showed that calculated M_{0} variations in
fatigue development processes can reflect a variation law in the MMM signal,
with certain differences. There is a numerical difference between H_{px} and M_{0} because the surface magnetic
field is much weaker than that within the ferromagnetic material. H_{px} increases after macro crack initiation caused by an
additional material demagnetization field and a leakage field near the crack
during cracking.
Keywords: Fatigue, metal magnetic memory, Jiles-Atherton model, dislocations
