Comparison of explicit and implicit finite element simulations of void growth and coalescence in porous ductile materials

As in several finite element studies, axisymmetric unit cell model calculations are used to study void growth to coalescence in a material containing a periodic array of voids. In this paper, a comparison of the analysis results obtained using transient explicit finite element method and static implicit method is presented. The unit cell is presumed to be remotely loaded in an axisymmetric fashion with predominant axial stress and overall stress triaxiality kept constant during the whole process of deformation. Computations pertaining to rate independent material, with different void shapes, overall stress triaxiality and material parameters are performed. A global view of the obtained results indicates that there is reasonably good agreement between both approaches. However, for low void aspect ratio and overall stress triaxiality, some difference exists especially in the softening regime, as compared to that of highest void aspect ratio and triaxiality. The proposed numerical technique is sounded out to be used to capture, at least to some extent, the representation of more complex fracture mechanisms accounting for the coalescence parameters.