| Summary: | 碩士 === 北臺灣科學技術學院 === 機電整合研究所 === 99 === As a result of products trending miniaturization in recent years, micro technology has been widely used in various areas. On the field of micro-forming of sheet metal, processing scale is close to hundreds of even dozens of micron scale. Due to the feature size of the finished product is almost as the microscopic size, so the deformation behavior of materials may not be very consistent to the macroscopic deformation behavior of traditional homogeneous material. In other words, the grain size will affect the behavior of macroscopic deformation. This article aims at the discussion of deformation behavior considering size effect on bead forming process of sheet metal. In this study, the test specimens were made by phosphor bronze sheets for bead forming test. The specimens with different thickness were firstly heated at different temperatures for obtaining the objective grain sizes. And the mechanical properties of specimen were acquired by using tensile test. Through the bead forming test with a bead forming machine, the curled angles, springback and curling load were measured and analyzed for investigating the geometric size effect and grain size effect during the bead forming process. In addition, this study adopted the finite element method with the macro deformation module of DEFORM-3D software code to simulating the bead forming process. The simulation results were compared with experimental results to estimate the validity of simulation with the macro deformation module considering the grain size effect in micro bead forming proces.
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