Analysis of Spherical Void Growth and Coalescence in Metal Plastic Straining Process
Ductile fracture occurs due to micro-void nucleation, growth and finally coalescence into micro-crack. In this study a new ductile fracture condition that based on the microscopic phenomena of void nucleation, growth and coalescence was proposed. Using this condition and combining with finite element model to predict the fracture locations in bulk metal forming. The macroscopic behavior of the material is described according to the flow rules of Levy-Mises. An idealized spherical void within an finite matrix is assumed. The void volume is calculated by taking the increasing volume of the continuum, caused by plastic straining, incorporated in the yield functions. In the model there includes the strain-hardening coefficient of the Ludwik-Holomom stress-strain relationship and concentration of stress. The accumulated damage value is a phenomenon in this model. The results show that it is in close accordance with observations of some experimental specimens. However, in order to obtaining the high trustiness many experiments have to be carried out.
Young-Jin Kim, Dong-Ho Bae and Yun-Jae Kim
C. H. Vu et al., "Analysis of Spherical Void Growth and Coalescence in Metal Plastic Straining Process ", Key Engineering Materials, Vols. 297-300, pp. 2837-2842, 2005