Spring-back principles of minimum potential energy and minimum complementary energy in metal forming processes are established by applying weighted residual method to the springback anti-couple equations and the springback principle of minimum potential energy is applied to calculate springback deformations of a cantilever beam and a curved beam.

By the use of weighted residual method to the springback anti-couple equations,springback principles of minimum potential energy and minimum complementary energy for thin sheets formed by bending are established.

The conceptions of springback anti coupled systems and equations are introduced in this paper.

This article first introducing the non-coupled systems and non-coupled equation of finite deformation springback.

Simulating method for the coupled spring in the common FEM program;