The influence of the three-dimensional effects of the distribution of the stress intensity factor in the numerical
calculation of plasticity-induced crack closure is analysed in this paper. The usual methodology assumes a constant
distribution of K along the thickness to obtain the effective stress intensity factor of the crack. This assumption
should not be transposed to models that intend to observe phenomena in the crack front vicinity, where 3-D
effects are a key aspect in the results. Through numerical simulations of both fracture and fatigue of through
thickness straight cracks (CT specimen in mode I), the local opening and closure moment of each crack node is
obtained and compared with previous one. Corrections are proposed for numerical methodology to obtain Kop
and Kcl distribution along the thickness