The Effect of the Non-singular T-stress Components on Crack Tip Plastic Zone under Mode I Loading

Theoretical and numerical analysis of the joint influence of the non-singular components of the T-stresses on the crack tip plastic zone estimated by the von Mises yield criterion is carried out under mode I loading in connection with specimen thickness. Calculations are performed for three thicknesses of the CT specimen.The amplitudes of the non-singular terms in the three-dimensional series expansion of the crack front stress field are the terms Txx and Tzz which describe in-plane and out-of-plane constraint, respectively. The plastic zone is analyzed for various combinations of the terms Txx to Tzz ratios.The plastic zone size distribution is mapped in the specimen thickness direction. It is shown that the plastic zone is affected by the Tzz-stress, i.e. there is strong effect of out-of-plane constraint on crack tip plastic zones. Crack tip plastic zone in the middle plane of the specimen decreases with the increase of specimen thickness.