Analysis of Superplastic Blow-Forming in Conical and Ellip-Cylindrical Dies

• Main Authors: Wu, Wen-Yuan, 鄔文元
• Other Authors: Hwang, Yeong-Maw
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/10237135478040996306

碩士 === 國立中山大學 === 機械工程研究所 === 85 === 　　A mathematical model using the finite difference method will be proposed to examine the plastic three-dimensional deformation behavior of the sheet in contact with the die during blow forming a thin sheet into a conical and ellip-cylindrical closed-die. A computer program will be developed to dtermine the forming presure-forming time diagram and the thickness distribution of the sheet at any constant during the blow-forming process or that of product under an optimized constant strain-rate. With this mathematical model developed, effects of various forming parameters such as the cone angle, friction coefficient, aspect ratio of die, etc., upon the optimized pressurization profile, forming time, and the thicknes distribution of products are discussed systematically. 　　Furthermore, employing 8090 Al-Li thin sheets as specimens, blow-forming experiments will also be conducted to verify the validity of this proposed model. After the validity and generality of this proposed model are verified through a series of comparisons between theoretical predictions and experimental measurements, this model will provide a series of optimized forming pressure-forming time diagrams which can be adopted to control the pressurization during blow-forming processes of a conical closed-die, so that the optimized thickness distributions of products can be obtained.