Drawbeads: to Be or Not to Be

Abstract

Drawbeads are often used in sheet metal forming processes in order to provide a better control of the material flow during forming processes. Experimentally it is well known that drawbeads play a very important role and are of paramount importance to the success of almost all complex forming operations. However, numerically there are still numerous difficulties to accurately model and describe drawbeads’ geometries and actions. Accordingly, in numerical models used in finite element codes, real drawbeads are typically replaced by some kind of “equivalent drawbead model”, which is required to take into account the bending/stretching processes experienced by a blank sheet passing along a drawbead and the equivalent drawbead restraining and lift forces, amongst others. The foremost question that arises is if such kind of “equivalent drawbead models” can or can not accurately describe and replace the real drawbeads and their actions. In fact, there is not one sole answer to such question, once it depends on the kind of process that is being carried out, and how drawbead relates itself with all the stamping process history.