Study of Formability Analysis in Cylindrical Micro Cup Drawing and Blank Optimization

• Main Authors: Shih-Chieh Chen, 陳世傑
• Other Authors: Fung-Huei Yeh
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/48354149498227387844

碩士 === 淡江大學 === 機械與機電工程學系碩士班 === 94 === This thesis discusses the simulation of micro cylindrical cup drawing and blank optimization. In order to prove that finite element method can effectively analyze the micro cylindrical cup drawing. The simulation of micro cylindrical flange cup drawing is firstly performed and compared with the experimental result in the journal paper. It shows that the result is the same. Besides, wrinkle dues to the improper gap of the blank holder is also discussed. Secondly, the simulation of micro cylindrical cup drawing is performed and compared with punch load, thickness distribution and cup height in the journal paper. Friction coefficient of the tools is predicted to verify the corresponding model in the experiments. This thesis also focus on the important factors of micro forming, which are friction coefficient, anisotropy of the sheet metal and size effect. In the discussion of size effect, this thesis combines the thickness and grain size into the stress-strain relation. A set of proper values is imported to predict the stress-strain curve by only one equation. The result of original stress-strain relation and stress-strain relation combines with the thickness and grain size is compared. The result shows the difference is within 5%. In the field of forming limit, this thesis uses the model that Dp/t=20 and check the limit drawing ratio (LDR) by the forming limit diagram (FLD).With the forming limit diagram, the reason and tendency of crack is realized and the result shows the limit drawing ratio is 2.3. In order to reduce the earing dues to anisotropy of sheet metal in the micro cylindrical cup drawing, true strain method combines weighting factor and Adaptive-Network-based Fuzzy Inference System (ANFIS) to predict the optimum blank with no earing. The distribution of the anisotropy of the sheet metal affects the applicability of true strain method. The result shows that if the anisotropic value in the 45 degree in the rolling direction is smaller, true strain method is suitable. If the anisotropic value in the 45 degree in the rolling direction is larger, weighting factor is used to modify the blank shape and sort the result into a data base as training data for ANFIS and a proper membership function is used. It shows good result of the modification. The research of this thesis can be the reference to the relative research in micro forming and blank optimization.