Influence of dynamic boundary conditions on preform design for deformation uniformity in backward simulation

Backward simulation using the finite element method (FEM) is an important approach for preform design. Different preforms can be obtained by imposing different dynamic boundary conditions in the backward simulation. In this paper, boundary conditions in the backward simulation are controlled by altering the time of boundary node separating from dies. And the relative non-uniform deformation degree is adopted to assess the preform design for deformation uniformity. Preform designs for the forging process of an airfoil section blade were obtained by using backward simulation approach and the influence of dynamic boundary conditions on preform design for deformation uniformity was investigated. The results are the followings: (1) shorting the separating time by a constant proportion leads to the slight change of the relative non-uniform deformation degree, which has a little effect on preform design for deformation uniformity; (2) decreasing the separating time of the nodes with large equivalent strain and increasing the separating time of the nodes with small equivalent strain simultaneously lead to the decrease of the relative non-uniform deformation degree, which may benefit the preform design.