State of the Art in Methods for Determining the Formability of Tube Hydroforming

In tube hydroforming,the methods for determining the formability of tube are the base of the hydrofoming technology.Therefore it is of significance for applying numerical simulation technique to hydroforming,optimizing process parameters and developing new products.Summarizes the existing methods for determining the formability of tube,the relevant methods mainly concentrate on the n,r value of tube for hydrofoming,geometric parameter and the forming limit diagram which is formed on the criterion for determining.Then,point out that the n,r value can be the standards of the tube formability,some further studies on the stress-based forming limit diagram are needed.