A new yield function for porous materials

Densification of sintered copper under uniaxial compression is analyzed by means of three different plasticity criteria—Shima and Oyane [S. Shima, M. Oyane, Plasticity theory for porous metals, Int. J. Mech. Sci. 18 (1976) 285–291], Doraivelu et al. [S.M. Doraivelu, H.L. Gegel, J.S. Gunasekera, J.C. Malas, J.T. Morgan, J.F. Thomas, A new yield function for compressible P/M materials, Int. J. Mech. Sci. 26 (9/10) (1984) 527–535] and Lee and Kim [D.N. Lee, H.S. Kim, Plasticity yield behaviour of porous metals, Powder Metall. 35 (1992) 275–279]. Theoretical predictions are compared with experimental data and served as a basis for developing a new yield function for compressible P/M materials. The proposed yield function is not only capable of providing a better agreement with the experiments as its implementation into an existing finite element computer program proves to be successful for the numerical modelling of a powder forged component.