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Title: Compressive Instability Phenomena During Springback

Springback in sheet metal product makes difficulties in die design because small strain causes large displacement. Especially for the sheet metal product having small geometric constraints, springback displacement may become severe. After first stage of stamping of outer case of washing machine, a large amount of springback is observed. The stamping depth of the outer case is small while stamping area is very large compared to the stamping depth, and therefore, there exists small geometric constraints in the formed part. Also, a compressive instability during the elastic recovery takes place and this instability enlarged the elastic recovery and dimensional error. In this paper, the compressive instability during the elastic recovery is analyzed using bifurcation theory. The final deformed shape after springback is obtained by bifurcating the solution path from primary to secondary. The deformed shapes obtained by the finite element analysis are in good agreement with the experimental data. The bifurcation behavior and the springback displacement for different forming depth are investigated.
Authors:
 [1] ;  [2] ;  [3]
  1. Dept. of Automotive Eng., Seoul National Uni. of Tech., 172 Gongneung-2Dong, No-won-Gu, Seoul, 139-743 (Korea, Republic of)
  2. Technical Center, 100 Technical Drive, Alcoa Center, PA15069-0001 (United States)
  3. Dept. of Mech. Eng., Kaist, 373-1, Kusung-Dong, Yusung-Gu, Taejon, 305-701 (Korea, Republic of)
Publication Date:
OSTI Identifier:
21061735
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 908; Journal Issue: 1; Conference: NUMIFORM 2007: 9. international conference on numerical methods in industrial forming processes, Porto (Portugal), 17-21 Jun 2007; Other Information: DOI: 10.1063/1.2740879; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALLOYS; BIFURCATION; COMPRESSIBILITY; ELASTICITY; ERRORS; FINITE ELEMENT METHOD; INSTABILITY; MATERIALS WORKING; METALS; PLASTICITY; SHEETS; STABILITY; STRAINS