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Shape Defects in The Flexible Roll Forming of Automotive Parts

  • Young Yun Woo
  • Sang Wook Han
  • Il Yeong Oh
  • Young Hoon MoonEmail author
Article
  • 45 Downloads

Abstract

Flexible roll forming allows variable cross sections of profiles to be made by using adaptive roll stands. The most common shape defects that occur during flexible roll forming are edge wave and longitudinal bow. These two defects are necessary to consider together for relatively thin-walled blanks because they usually occur simultaneously during flexible roll forming. To understand the occurrence of these defects, finite element (FE) simulations based on the rigid shell concept were carried out using three blanks with different shapes: trapezoid, concave, and convex. The FE analysis on the flexible roll forming process was performed first, and then the gap of rigid shell has been decreased for reducing the longitudinal bow in roll formed blank. The reduction of longitudinal bow in the web part usually causes edge wave in the flange part. The occurrence of shape defects is investigated based on the relationships among edge curvature, longitudinal stress at the edge, and longitudinal bow height. When longitudinal bow is reduced, the longitudinal stress at the edge of roll formed blank is changed from tensile to compressive in convex blank but in concave blank, tensile residual stress increases. Edge waves occur in the flanges of trapezoid and convex blanks as a result of decreased longitudinal bow. Lab-scale flexible roll forming experiments show multi-stand forming with a leveling roll is desirable to reduce both edge wave and longitudinal bow.

Key Words

Flexible roll forming Longitudinal bow Edge wave Web warping Flange wrinkling FEM Leveling roll 

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References

  1. Abvavi, A., Rolfe, B., Hodgson, P. D. and Weiss, M. (2015). The influence of residual stress on a roll forming process. Int. J. Mechanical Sciences, 101-102, 124–136.CrossRefGoogle Scholar
  2. Bidabadi, B. S., Naeini, H. M., Tehrani, M. S. and Barghikar, H. (2016). Experimental and numerical study of bowing defects in cold roll-formed, U-channel sections. J. Constructional Steel Research, 118, 243–253.CrossRefGoogle Scholar
  3. Bui, Q. V. and Ponthot, J. P. (2008). Numerical simulation of cold roll forming process. J. Materials Processing Technology 202, 1-3, 275–282.CrossRefGoogle Scholar
  4. Carpinteri, A., Lacidogna, G., Montrucchio, B. and Cammarano, S. (2014). The effect of the warping deformation on the structural behaviour of thin-walled open section shear walls. Thin-Walled Structures, 84, 335–343.CrossRefGoogle Scholar
  5. Groche, P., Henkelmann, M., Goetz, P. and Berner, S. (2008). Cold rolled profiles for vehicle construction. Archives of Civil and Mechanical Engineering, 8, 2, 31–38.CrossRefGoogle Scholar
  6. Groche, P., Zettler, A., Berner, S. and Schneider, G. (2011). Development and verification of a one-step-model for the design of flexible roll formed parts. Int. J. Material Forming, 4, 4, 371–377.CrossRefGoogle Scholar
  7. Halmos, G. T. (2006). Roll Forming Handbook. CRC Press. Boca Raton, Florida, USA.Google Scholar
  8. Jiao, J., Rolfe, B., Mendiguren, J. and Weiss, M. (2015). An analytical approach to predict web-warping and longitudinal strain in flexible roll formed sections of variable width. Int. J. Mechanical Sciences, 90, 228–238.CrossRefGoogle Scholar
  9. Joo, B. D., Han, S. W., Shin, S. G. R. and Moon, Y. H. (2015). Flexible roll forming process design for variable cross-section profile. Int. J. Automotive Technology 16, 1, 83–88.CrossRefGoogle Scholar
  10. Kang, B. H., Lee, S. M., Shon, S. M. and Moon, Y. H. (2007). Forming various shapes of tubular bellows using a single-step hydroforming process. J. Materials Processing Technology 194, 1-3, 1–6.Google Scholar
  11. Kasaei, M. M., Naeini, H. M., Liaghat, G. H., Silva, C. M. A., Silva, M. B. and Martins, P. A. F. (2015). Revisiting the wrinkling limits in flexible roll forming. J. Strain Analysis for Engineering Design, 50, 7, 528–541.CrossRefGoogle Scholar
  12. Kim, J. H., Woo, Y. Y., Hwang, T. W., Han, S. W. and Moon, Y. H. (2016). Effect of loading pattern on longitudinal bowing in flexible roll forming. J. Mechanical Science and Technology, 30 12, 5633–5639.CrossRefGoogle Scholar
  13. Lindgren, M. (2007). An improved model for the longitudinal peak strain in the flange of a roll formed Uchannel developed by FE-analyses. Steel Research International 78, 1, 82–87.CrossRefGoogle Scholar
  14. Moon, Y. H., Kim, D. W. and Van Tyne, C. J. (2008). Analytical model for prediction of sidewall curl during stretch-bend sheet metal forming. Int. J. Mechanical Sciences 50, 4, 666–675.CrossRefzbMATHGoogle Scholar
  15. Park, K. S., VanTyne, C. J. and Moon, Y. H. (2007). Process analysis of multistage forging by using finite element method. J. Materials Processing Technology, 187-188, 586–590.CrossRefGoogle Scholar
  16. Park, J. C., Yang, D. Y., Cha, M., Kim, D. and Nam, J. B. (2014). Investigation of a new incremental counter forming in flexible roll forming to manufacture accurate profiles with variable cross-sections. Int. J. Machine Tools and Manufacture, 86, 68–80.CrossRefGoogle Scholar
  17. Rezaei, R., Naeini, H. M., Tafti, R. A., Kasaei, M. M., Mohammadi, M. and Abbaszadeh, B. (2017). Effect of bend curve on web warping in flexible roll formed profiles. Int. J. Advanced Manufacturing Technology 93, 9-12, 3625–3636.CrossRefGoogle Scholar
  18. Safdarian, R. and Moslemi Naeini, H. M. (2015). The effects of forming parameters on the cold roll forming of channel section. Thin-Walled Structures, 92, 130–136.CrossRefGoogle Scholar
  19. Tehrani, M. S., Hartley, P., Naeini, H. M. and Khademizadeh, H. (2006). Localised edge buckling in cold roll-forming of symmetric channel section. Thin-Walled Structures 44, 2, 184–196.CrossRefGoogle Scholar
  20. Tran, D. C., Tardif, N., El Khaloui, H. and Limam, A. (2017). Thermal buckling of thin sheet related to cold rolling: Latent flatness defects. Thin-Walled Structures, 113, 129–135.CrossRefGoogle Scholar
  21. Woo, Y. Y., Han, S. W., Hwang, T. W., Park, J. Y. and Moon, Y. H. (2018). Characterization of the longitudinal bow during flexible roll forming of steel sheets. J Materials Processing Technology, 252, 782–794.CrossRefGoogle Scholar
  22. Yi, H. K., Kim, D. W., Van Tyne, C. J. and Moon, Y. H. (2008). Analytical prediction of springback based on residual differential strain during sheet metal bending. Proc. Institution of Mechanical Engineers, Part C: J. Mechanical Engineering Science 222, 2, 117–129.Google Scholar

Copyright information

© KSAE 2019

Authors and Affiliations

  • Young Yun Woo
    • 1
  • Sang Wook Han
    • 1
  • Il Yeong Oh
    • 1
  • Young Hoon Moon
    • 1
    Email author
  1. 1.School of Mechanical EngineeringPusan National UniversityBusanKorea

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