FEM을 이용한 셀프 피어싱 리벳 냉간압조 해석

초록

Self-piercing rivets (SPR) are manufactured using multistage cold heading of a constant length of steel wire rods. This study attempted to design molds for tolerable loading to material and make the metal flow of the SPR lines parallel and without cusp. During this process, beyond the existing virtual experiment, which was limited to the plastic deformation of the SPR material, the analysis of the molds’ stress, elastic deformation, and wear were simultaneously performed. This study mainly aimed to mimic the multistage cold process of the heading machine for manufacturing SPR using DEFORM (commercial finite element method software) and minimize differences between with manufacturing sites. Furthermore, deviating from the existing mold development process (shape design with trial and error), the development efficiency was maximized by the reduction of both the mold development period and the mold cost. Finally, the hardness homogenization of the manufactured SPR with a tempering finished was verified.

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