An Inverse Finite Element Approach to Calculate Full-Field Forming Strains

A methodology to calculate surface strains from a rectangular grid placed on a forming blank is introduced. This method consists of treating the grid points as nodes of a finite element (FE) model and assigning elements to the grid. The strains are then computed following FE analysis. If higher order elements are used, also more information within the element can be obtained which allows a coarser grid without loss of accuracy. This is the major advantage of the approach presented herein.