Interaction of two closely spaced voids during growth to coalescence

For ductile materials failure often occurs by the growth of voids to coalescence, leading to fibrous fracture. Also, void clustering is important in practice. In the present paper, the focus of investigation is on the interaction between two closely spaced voids with much larger distance to other neighboring voids. A remeshing procedure is employed to be able, to account for the large strains that develop around a void. The numerical analyses are carried out for different values of the ratio between the average true stresses in the transverse direction and in the main tensile direction. For a high stress ratio approaching unity, the very high stress triaxiality gives rapid void growth, whereas a stress state closer to uniaxial plane strain tension gives slower growth with void elongation in the tensile direction. In conclusion, it is shown that the onset of void coalescence is predicted much earlier for high stress triaxiality.