Inverse parameter estimation of the Cowper-Symonds material model for electromagnetic free bulge forming

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• 作者：Hak-Gon Noh ; Kyunghoon Lee ; Beom-Soo Kang…
• 关键词：Electromagnetic forming process ; High ; speed forming ; Reduced ; order modeling ; Krigging method ; Nonlinear least square
• 刊名：International Journal of Precision Engineering and Manufacturing
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：17
• 期：11
• 页码：1483-1492
• 全文大小：1,356 KB
• 刊物类别：Engineering
• 刊物主题：Industrial and Production Engineering
  Materials Science
  
• 出版者：Korean Society for Precision Engineering, in co-publication with Springer Verlag GmbH
• ISSN：2005-4602
• 卷排序：17

文摘

Electromagnetic forming (EMF) processes require no more than about 300 μs to complete. Given the high speeds involved (150 m/s to 250 m/s), it is almost impossible to determine the flow stress through the application of a mechanical property test. In this study, the flow stress of Al 1100-O at high speeds was predicted by inverse parameter estimation. The constitutive equation of flow stress is given by the Cowper–Symonds model. Firstly, a practical experiment process is set up with a spiral coil for the EMF-free bulge test. To compare the results of our experiments with the numerical results, an EMF simulation was prepared and the X- and Zdisplacements of the sheet on the center line were measured to compare them with the results of experiments as obtained using 2- D scanning. To find the optimal properties for the EMF process, a reduced-order model (ROM) with the Kirging method was adopted to form the basis. From this model, an inverse parameter estimation was conducted using the nonlinear least squares method with a genetic algorithm. By comparing the results of the experiments with the ROM results, the validity of the flow stress obtained by an inverse estimation was validated.