Ductile fracture has been described by many models on different scales; namely, continuum, micro, miso & even on atomistic scales. The widely accepted model is the micromechanical phenomological , Gurson model.
Gurson assumes that material is porous with spherical voids. Under deformation, original voids grow & new voids are nucleated. Failure become pronounced in the third stage; coalescence. Coalescence mechanism occurs either by localized shear at ligaments between voids or by their preferential growth parallel to the axis of highest principal stress as reported in literature. Literature includes many void Coalescence models; namely Thomason, Pardoen and Hutchinson (P&H), Benzerga, Ragab, and McClintock.
In this work, FEA is used to model materials obeying Gurson function on a uniaxial tensile test. The coalescence criterions are introduced to the FEA solver, Abaqus via a user subroutine. The onset of coalescence is determined and compared to experimental results.