FRICTION TECHNIQUE FOR DETERMINING FORMING LIMIT CURVES

Abstract

ABSTRACT A new method for establishing the Forming Limit curve (FLC) in sheet metal forming is introduced in this work. The method is based on varying the strain path by changing the coefficient of friction between the punch and the blank. Three finite element simulations are used for the hemispherical punch stretching test. One simulation is for the positive minor strain side and two are for the negative minor strain side of the FLC. Relations between the major and the minor strains are deduced from the results of these simulations. These relations are used to draw the FLC. The curves obtained were compared with experimental results and found to have a good agreement with them.KEYWORDS strain path, forming limit curve ABSTRACT A new method for establishing the Forming Limit curve (FLC) in sheet metal forming is introduced in this work. The method is based on varying the strain path by changing the coefficient of friction between the punch and the blank. Three finite element simulations are used for the hemispherical punch stretching test. One simulation is for the positive minor strain side and two are for the negative minor strain side of the FLC. Relations between the major and the minor strains are deduced from the results of these simulations. These relations are used to draw the FLC. The curves obtained were compared with experimental results and found to have a good agreement with them.KEYWORDS strain path, forming limit curve