Abstract: On the basis of von Karman equations and using the general bifurcation theory, the elastic instability of an orthotropic elliptic plate whose edge is subjected to a uniform plane compression is discussed.Following the well-known Liapunov-Schmidt process the existance of bifurcation solution at a simple eigenvalue is shown and the asymptotic expression is obtained by means of the perturbation expansion with a small parameter.Finally, by using the finite element method, the critical loads of the plate are computed and the post-buckling behavior is analysed.And also the effect of material and geome trie parameters on the stability is studied.

Key words: orthotropic, elliptic plate, elastic instability, critical load, bifurcation solution, post-buckling behavior