Analysis of Contact Stresses in High Speed Sheet Metal Forming Processes

In high speed metal forming, determination of contact stresses applied to forming dies is necessary in order to identify the requirements to the die material. Contact stresses greatly control the die design due to their effects on die durability. Very high contact stresses and fracture under impulsive loading have been reported in literature on contact type of high speed forming. In pulsed forming operations using electro-hydraulic forming (EHF), a work piece is often accelerated into the die cavity of a desired shape resulting in a substantial impact pressure on the die. Contact algorithm and mesh size play an essential role in providing accurate results in such high speed processes. Using the soft contact model with an appropriate control of the penetration value provided stable and consistent contact stresses.