Volume :1 , Issue :1 ,Page :14-18

Abstract :This note is intended to present a new and corre cted version of generalized yield criteria of porous sintered powder metallurgy metals, which was proposed in our earlier paper (Narayanasamy et.al.,2001). It is noticed that equations (14)-( 17) are dimensionally and mathematically incorrect. This is a slip in our part. In the case of anisotro pic non-porous sheet metals with the parameters m=2, n=2 and p=1, mathematical expression for yield equation obtained from generalized yield equation (see equation (15)) in our paper (Naray anasamy et.al.,2001) ha s not been reduced to the corresponding cited equation (20) which was taken from the bo ok written by Johnson and Mellor(1973). It is wrongly mentioned in ou r paper (Narayanasamy et.al., 2001) that when substituting m=2, p=1 and n=2 in Eq.(17), Eq.(24) is obtained, which is impossibl e. It is further observed that Eqs.(14) and (22) are not the same when m=2 and p=1. At this junc ture, it is pertinent to pin-point out that the theoretical prediction of forming limit strain, wrinkl ing tendency, localized necking behaviour etc. of sheet materials using improper generalized yield cr iteria leads to wrong conc lusions which, in turn, could not be helpful for us to have a crystal clear understanding the actual ch aracteristics of plastic deformation of sheet metals and ma terials and to the development of designing tools for manufacturing process. Based on the forgoing view s, it is pivotal to propose a new fo rm of genreralized yield equation and obtain the corresponding particular cases that form the content of the present paper.