Numerical models capable of modeling magnetic flux leakage (MFL) metho
ds of nondestructive testing are of significant interest to industry.
The nonlinear nature of the MFL problem necessitates the use of an ite
rative model, thereby resulting in excessive computational effort. Thi
s paper describes an approach for developing an equivalent linear mode
l (ELM) where the ferromagnetic region is appropriately partitioned in
to different domains with each domain being assigned a constant permea
bility value depending on the magnetization level and the flaw size. T
he nonlinear behavior of the multi-layered object is then modeled usin
g a linear MFL model. The strategy results in significant computationa
l savings without a substantial loss in accuracy. Results supporting t
he validity of the approach have been obtained using a 3D magnetostati
c finite element (FE) model.