AbstractA cohesive interface element for ductile tearing of thin structures modelled by plane-stress continuum or shell elements is presented which accounts for thickness reduction. This modification prevents localisation of plastic deformation in the adjacent continuum elements often inhibiting crack extension and leading to divergence of the numerical simulations. Some examples show the performance of the elements. Ductile crack extension in a plane centre-cracked panel and in a compact specimen of Al 5083 is simulated and compared with experimental data. Parametric studies on shell structures demonstrate possible applications for the analysis of residual strength of cracked aircraft fuselages.