Deformation mechanics in single-point and accumulative double-sided incremental forming

Original Article

Abstract

Single-point incremental forming (SPIF) uses one small hemispherically ended tool moving along a predefined toolpath to locally deform a completely peripherally clamped sheet of metal such that the sum total of the local deformations yields the final desired shape of the sheet. While SPIF is characterized by greater formability than conventional forming processes, it suffers from significant geometric inaccuracy. Accumulative double-sided incremental forming (ADSIF) is a substantial improvement over SPIF in which one hemispherically ended tool is used on each side of the sheet metal. The supporting tool moves synchronously with the forming tool, therefore acting as a local but mobile die. ADSIF results in considerably enhanced geometric accuracy and increased formability of the formed part as compared to SPIF. In light of the aforementioned advantages of ADSIF as compared with SPIF, an investigation of the mechanics associated with the ADSIF process, which has yet to be presented in the literature, is warranted. The present study sheds light on the differences in deformation mechanisms between SPIF and ADSIF. Finite element analyses are performed to simulate deformation in the two processes, and a detailed analysis of the deformation history is presented. It is shown that the presence of the supporting tool in ADSIF elicits substantial differences in the plastic strain, hydrostatic pressure, and shear strains as compared to SPIF. The implications of these trends on the prevalent modes of deformation in ADSIF along with possible explanations for increased formability observed in the process arediscussed.

Keywords

Accumulative double-sided incremental forming Single-point incremental forming Deformation mechanics Finite element analysis 

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References

  1. 1.
    Allwood JM, Shouler DR (2009) Generalised forming limit diagrams showing increased forming limits with non-planar stress states. Int J Plast 25(7):1207–1230. doi:10.1016/j.ijplas.2008.11.001 CrossRefMATHGoogle Scholar
  2. 2.
    Emmens W, van den Boogaard A (2009) An overview of stabilizing deformation mechanisms in incremental sheet forming. J Mater Process Technol 209(8):3688–695. doi:10.1016/j.jmatprotec.2008.10.003 CrossRefGoogle Scholar
  3. 3.
    Fan J, Tang C, Tsui C, Chan L, Lee T (2006) 3D finite element simulation of deep drawing with damage development. Int J Mach Tools Manuf 46(9):1035–1044. doi:10.1016/j.ijmachtools.2005.07.044 CrossRefGoogle Scholar
  4. 4.
    Jackson K, Allwood J (2009) The mechanics of incremental sheet forming. J Mater Process Technol 209(3):1158–1174. doi:10.1016/j.jmatprotec.2008.03.025 CrossRefGoogle Scholar
  5. 5.
    Malhotra R, Cao J, Ren F, Kiridena V, Cedric Xia Z, Reddy NV (2011) Improvement of geometric accuracy in incremental forming by using a squeezing toolpath strategy with two forming tools. J Manuf Sci Eng Trans ASME 133(6):603–611. doi:10.1115/1.4005179 CrossRefGoogle Scholar
  6. 6.
    Malhotra R, Cao J, Beltran M, Xu D, Magargee J, Kiridena V, Xia ZC (2012a) Accumulative-DSIF strategy for enhancing process capabilities in incremental forming. CIRP Ann Manuf Technol 61(1):251–254. doi:10.1016/j.cirp.2012.03.093 CrossRefGoogle Scholar
  7. 7.
    Malhotra R, Xue L, Belytschko T, Cao J (2012b) Mechanics of fracture in single point incremental forming. J Mater Process Technol 212(7):1573–1590. doi:10.1016/j.jmatprotec.2012.02.021 CrossRefGoogle Scholar
  8. 8.
    Meier H, Magnus C, Smukala V (2011) Impact of superimposed pressure on dieless incremental sheet metal forming with two moving tools. CIRP Ann Manuf Technol 60(1):327–330. doi:10.1016/j.cirp.2011.03.134 CrossRefGoogle Scholar
  9. 9.
    Silva MB, Skjoedt M, Atkins AG, Bay N, Martins PAF (2008) Single-point incremental forming and formability failure diagrams. J Strain Anal Eng Des 43(1):15–35. doi:10.1243/03093247JSA340 CrossRefGoogle Scholar
  10. 10.
    Silva MB, Skjoedt M, Bay N, Martins PAF (2009) Revisiting single-point incremental forming and formability/failure diagrams by means of finite elements and experimentation. J Strain Anal Eng Des 44(4):221–234. doi:10.1243/03093247JSA522 CrossRefGoogle Scholar
  11. 11.
    Xue L (2007) Damage accumulation and fracture initiation in uncracked ductile solids subject to triaxial loading. Int J Solids Struct 44(16):5163–5181. doi:10.1016/j.ijsolstr.2006.12.026 CrossRefMATHGoogle Scholar
  12. 12.
    Xue L (2010) Eng Fract Mech 77(8):1275–1297. doi:10.1016/j.engfracmech.2009.12.008

Copyright information

© Springer-Verlag London 2013

Authors and Affiliations

  • Jacob Smith
    • 1
  • Rajiv Malhotra
    • 1
  • W. K. Liu
    • 1
  • Jian Cao
    • 1
  1. 1.Department of Mechanical EngineeringNorthwestern UniversityEvanstonUSA

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