A study of the evolution of crack tip plasticity along a crack front

In this work, we present a detailed numerical analysis of the evolution of the plastic zone through the thickness of compact tension aluminium alloy specimens. An ultra-fine non-linear finite element model was used to characterise with great detail the size and shape of the plastic zone for different thicknesses. The numerical plastic zone was compared in size and shape with the plane strain and plane stress Dugdale plastic zones. In general, the maximum plastic zone was found to be in the interior but closer to the surface than to the mid plane. We also propose an equivalent bi-dimensional plastic zone for converting the complex 3D distribution into a 2D plastic zone. Finally, the numerical results were validated using experimental displacement data measured optically from the surface of the specimen.