Forming and Yield Criteria of Sheet Metals for Aero-engine Casings

Sheet metal casings, main components of aero-engines, have the following features:complex structure, difficult forming of material and internal residual stress after forming. With the development of computer, numerical simulation has become a main auxiliary means of sheet forming, and yield criterion is the foundation of numerical simulation. The forming performances of sheet metals for aero-engine casings were introduced, yield criteria of isotropic and anisotropic materials were summarized. It is assumed that yield criteria should be based on yield locus, uniaxial yield stress and plastic anisotropy parameters. It is pointed out that the future yield criteria may be developed according to new yield criterion, yield locus under nonlinear loading, and innovative experimental method.