The Analysis of Forming Limit in the Re-Penetration Process of the Hole-Flanging of Sheet Metal
| Autor: | Jen-De Chen, 陳振德 |
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| Rok vydání: | 2004 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 92 A methodology for formulating an elasto-plastic finite element model is developed to analyze the direct penetration and re-penetration in the hole-flanging process. The model is based on the Updated Lagrangian Formulation, Prandtl-Reuss flow rule, and Hill’s yield criterion. Simulation results include the relationship between punch load and punch stroke, the variation of the workpiece thickness, the distribution of the stress, the distribution of the strain, and the forming limit. Two sets of different dimensional tools are designed for experiments to verify the reliability of the program. By using different dimensional tools for re-penetration process, the study describes the effect that the direct penetration and re-penetration have on the workpiece. Besides, the study also discusses the comparison of experiments and numerical analysis between penetration and re-penetration processes. According to the simulation and experiment results, the re-penetration punch load is less than the direct penetration punch load. The maximum punch load increases remarkably when the profile radius of cylindrical punch and initial hole of blank decrease. Moreover, the re-penetration has better formability than the direct penetration in the same condition. According to the definitions of forming limit ratio, the re-penetration process, that can be improved from 2.70 to 2.97. Therefore, the simulation results show good agreement with the experiments that can be used to verify the reliability and accuracy of the elasto-plastic finite element program in this study. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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