On the mechanism of void growth and the effect of straining mode in ductile materials

Finite element analysis is employed to investigate void growth embedded in elastic-plastic matrix material. Axisymmetric and plane stress conditions a re considered. The simulation of void growth in a unit cell model is carrie d out over a wide range of triaxial tensile stressing or large plastic stra ining for various strain hardening materials to study the mechanism of void growth in ductile materials. Triaxial tension and large plastic strain enc ircling around the void are found to be of most importance for driving void growth. The straining mode of incremental loading which favors the necessa ry strain concentration around void for its growth can be characterized by the vanishing condition of a parameter called "the third invariant of gener alized strain rate". Under this condition, it accentuates the internal stra in concentration and the strain energy stored/dissipated within the materia l layer surrounding the void. Experimental results are cited to justify the effect of this loading parameter. (C) 2000 Elsevier Science Ltd. All right s reserved.