Experimental and finite element analysis of spring back in sheet metal forming

This paper presents an experimental and numerical study of 2D draw bend spring back phenomenon occurring during the forming operations of steel blank strips. The prediction of this phenomenon is important to evaluate the design of tools used mainly for stamping. In order to truthfully validate materials parameters, both experimental and Finite Elements (FE) analyses were cross compared. This investigation gave a very truthful validation of the FE model, proving its capability to predict spring back values and sidewall curl in 2D draw bending. The experimental device gives better reliable results about spring back criterion for approaching to the real industrial forming conditions. This model is a simple and an efficient way to take apart the responsibilities between the steel maker (steel selection) and the sheet stamping designer (selection of the forming conditions) in the metal stamping process. [Received 24 April 2006, Accepted in revised form 19 January 2007]