3.1 Finite element modelling of MFL signals from dents: Developing effective magnetic models of expected MFL behaviour involved incorporating both geometry and stress effects. Geometry effects are relatively straightforward to account for, however stress effects are more problematic. As mentioned previously, our earlier work3 indicated that MFL signals were sensitive to elastic residual strain but not to plastic deformation. Therefore, the first stage of our modeling work involved finite element analysis of the elastic stress pattern around a dent using finite element stress analysis.