The Theoretical Research on the Blanking of a Sheet Material

In this paper, the author applied the theory of limit analysis to a theoretical investigation of the blanking process. In Part I, the statically admissible stress field in a sheet material was analysed on the assumptions : (1) The sheet material is a non-hardening plastic-rigid body. (2) The material near tool edges is approximately in the state of plane strain. (3) The stress field consists of several regions of constant stress separated by straight lines of discontinuity. In Part II, the deformation process of the sheet material was devided into four stages, and the kinematically admissible velocity field was analysed in each stage. Furthermore, comparing the solution of the stress field with that of the velocity field, an exact solution of the blanking force was obtained for blanking with smooth punch and die.