Size Effects in Winding Roll Formed Profiles: A Study of Carcass Production for Flexible Pipes in Offshore Industry

Abstract:

Carcass production of flexible offshore oil and gas pipes implies winding and interlocking of a roll formed stainless steel profile around a mandrel in a spiral shape. The location of the dividing point between the left and right half of the s-shaped profile in the finished carcass is very important as it directly influences carcass flexibility. The target location of the dividing point can be difficult to achieve since undesired degrees of freedom in the winding stage allows the profile to change geometry. The present work investigates this issue by performing production tests of a single carcass profile size on three mandrel sizes showing a size effect to be evident; smaller mandrel size increases a shift of the dividing point during initial mandrel contact in the winding stage. The cause is high strains in the open profile, which are minimized by the material moving closer to profile neutral plane. Other parameters such as profile entry angle on the mandrel and spiral pitch are likely to have significant importance. Proper dividing point position is shown to be obtainable by adjusting the profile in the roll forming stage. The profile rolling is successfully modeled by Finite Element Analysis (FEA), whereas a simplified FE-model of the subsequent winding operation shows that full interlock modeling is required for proper prediction of profile deformation.

• Periodical: Key Engineering Materials (Volume 549)
• Pages: 117-124
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.549.117
• Online since: April 2013
• Authors: Peter Søe Nielsen, Morten Storgaard Nielsen, Nils Bay
• Keywords: Duplex Stainless Steel, Finite Element Analysis (FEA), Free-Forming, Roll Forming, Sheet Metal

References

[1] Information on http://www.nov.com/Production/Floating_Production_Solutions/Flexible_Pipe_ Systems.aspx, accessed on Dec. 06 - (2012)

[2] Z. Chen, R.L Reuben and D.G. Owen: The deformation mechanics of interlock tubes, Strain Vol. 28 Issue 3, pp.99-106, August (1992)

DOI: 10.1111/j.1475-1305.1992.tb00802.x

[3] A.E. Tekkaya and P.A.F. Martins: Accuracy, reliability and validity of finite element analysis in metal forming: a user's perspective, Engineering Computations, Vol. 26 Issue 8, pp.1026-1055, (2009)

DOI: 10.1108/02644400910996880

[4] M. Lindgren: Experimental and computational investigation of the roll forming process, Doctoral thesis / Luleå University of Technology, 2009, ISBN: 978-91-7439-031-5

[5] T. Hama, K. Iguchi, H. Hishida and H. Takuda: Roll forming simulations of a steel sheet using various finite element method codes, 12th International Conference on Metal Forming, Cracow Poland, SEP 21-24, (2008)

[6] Q.V. Bui and J.P. Ponthot: Numerical simulation of cold roll-forming processes, Journal of Materials Processing Technology, Vol. 202 Issue 1-3, pp.275-282, (2008)

DOI: 10.1016/j.jmatprotec.2007.08.073

[7] LS-DYNA 971 Manual on http://www.dynasupport.com/news/ls-dyna-971-manual-pdf, accessed on Dec. 06 - (2012)