Mathematical modelling of spring back in sheet forming

The sheet panels are essential element of aircraft Structures. These panels can be formed by different processes including bending, stretching, bend-stretch, and hydroforming etc. Spring back phenomenon plays an important role during the forming process. An effort has been applied to develop the spring back mathematical model based on analytical and experimental results obtained from CNC folding machine. This analytical model is based on energy principal catering linear strain hardening. Radius of curvature after removal of applied moment has been predicted. Afterwards spring back factor has been devised from experimental results. Strains and stresses during forming process are also predicted. (author)