Assessing　the　effect　of　defect　induced　stresses　on　magnetic　flux　leakage　(MFL)　signals　is　a　complicated　task　due　to　nonlinear　magnetomechanical　coupling.　To　facilitate　the　analysis,　a　multi-physics　finite　elemental　simulation　model　is　proposed　based　on　magnetomechanical　theory.　The　model　works　by　quasi-statically　computing　the　stress　distribution　in　the　specimen,　which　is　then　inherited　to　solve　the　nonlinear　magnetic　problem　dynamically.　The　converged　solution　allows　identification　and　extraction　of　the　MFL　signal　induced　by　the　defect　along　the　sensor　scanning　line.　Experiments　are　conducted　on　an　AISI　1045　steel　specimen,　i.e.　a　dog-bone　shaped　rod　with　a　cylindrical　square-notch　defect.　The　experiments　confirm　the　validity　of　the　proposed　model　that　predicted　a　linear　dependency　of　the　peak-to-peak　amplitude　of　the　normalized　MFL　signal　on　applied　stress.　Besides　identifying　the　effect　of　stress　on　the　induced　MFL　signal,　the　proposed　model　is　also　suitable　for　solving　the　inverse　problem　of　sizing　the　defects　when　stress　is　involved.