| Whitney's lemma is an important theorem in the local singularity theory of germs of C∞ functions. In this paper, we prove the global conclusion of this lemma. Based on this generalization, the plastic yield criterion for certain kind materials is discussed in detail. We find that for this kind materials the most general form of the plastic yield criterion should be g(J,J′2,J′32)=0 . Finally, we shall also give some practical examples for explanation. |
