The use of the finite-element method to design an optimized tool for the plain-strain punch stretching test

The tool geometry of the plane-strain punch stretching (PSS) test was optim ized by computer simulation to assure test reliability. A three-dimensional , finite-element method (FEM) was used to optimize the three design variabl es: the punch length, punch crown, and punch corner radius. Experiments con firmed the plane strain condition predicted by experiment. From this simula tive study, we can conclude that the optimized punch shape of the PSS test, with:ellipsoidal shape, exhibits stable performance when evaluating the st amping formability of sheet materials. Clearly, the optimized punch geometr y with a punch crown of 3 mm, punch corner radius of 6 mm, and punch length of 72 mm shows better reliability compared with that of the original PSS t est.