Yield strength of porous materials

The ductile failure of porous metallic materials is studied here using both Limit Analysis (LA) methods, a problem treated by Gurson with his famous k inematic approach in 1977. The present work is devoted to determining the s trength of porous materials with long circular cylindrical cavities in the case of plane stress. The numerical methods developed here use the Hill-Man del method based on the homogenization theory of heterogeneous media within the LA framework. The use of kinematic and static approaches gave an excel lent estimation of the yield criterion for all the cases studied. The numer ical results based on LA methods have been compared with analytical arid se mi-analytical yield domain expressions proposed by different authors. The r esults show that the Richmond model was the most accurate in teens of our p redictions. (C) 2001 Academie des sciences/Editions scientifiques et medica les Elsevier SAS.