© 2015 Elsevier B.V. Three known dislocation density based models are compared to each other, and to available experimental results. All three models were embedded into ANSYS finite element (FE) software and firstly utilised to predict aluminium and copper transformations (dislocation density evolution and the resulting grain size) in a result of a single pass of equal channel angular pressing (ECAP). It is demonstrated that for the studied problem dislocation density evolution under severe plastic deformation (SPD) can be precisely predicted utilizing simple classical model. One of the models was utilized to predict defect structure evolution for the series of ECAP passes. Simulations have revealed that within the framework of the proposed model the increase of the dislocation density on ECAP pass is proportional to yield strength increment on the previous pass for both studied materials. This fact gives grounds to a proposal of a semi-analytical approach, predicting dislocation density evolution in a result