Aspects of the Gurson Model and Its Applications

Ductile fracture in metals can involve the generation of considerable porosity caused by nucleation, growth and coalescence of microvoids. This process takes place on micro-level and can not describe by traditional constitutive laws such as von Mises theory. Hence, A. L. Gurson developed a theory which takes account of void growth and showed the role of hydrostatic stress in plastic yield and void growth. In this model the void volume fraction f (the portion of void in the material) is the single damage parameter; its evolution is defined by the incompressibility of the matrix material. (For Lameitre's model the damage variable D is relevant.) To model the material damage by using the Gurson damage approach a series of single elements including different types of loading are used. In the single element cases the results of the Gurson model and von Mises are also compared. In calculations the MARC finite elements software is used to calculate stress, strains and f the void volume fraction.