In this paper, the Young's modulus and the yield strength of the strip are considered in order to modify the deformation length analysis proposed by Bhattacharyya et al. New analytical equations are developed assuming an elastic-perfectly plastic material behaviour and the deformation length analysed for the simple case of roll forming a U-channel; the analytical results are verified by comparison with experimental data found in the literature. The proposed elastic-plastic deformation length is shorter than Bhattacharyya's which is rigid-perfectly plastic. It is observed that the influence of elastic properties on the deformation length is not as significant as the plastic properties; however, the authors believe that the elastic effects become more important under conditions where a major area of the strip is under elastic deformation such as when the flange length is long.
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R.A. Tafti et al.Reference to this paper should be made as follows: Tafti, R.A., Naeini, H.M., Tehrani, M.S., Rolfe, B.F. and Weiss, M. (2013) 'Theoretical extension of elastic-perfectly plastic deformation length in roll forming of a channel section', Int. J. Materials and Product Technology, Vol. 47, Nos. 1/2/3/4, pp.33-45. Biographical notes: Roohollah Azizi Tafti is a PhD candidate of Manufacturing Engineering at the Tarbiat Modares University where he also received his Master's degree in 2007. His research interests include deformation analysis in sheet metal forming processes and finite element simulation. He has been working on the roll forming process since 2005. Hassan Moslemi Naeini received his PhD in 2000 from the University of Tokyo in Japan, in Manufacturing Engineering. He is currently a faculty member at the Tarbiat Modares University, IR Iran. His research interests include sheet metal forming analysis focusing on roll forming process, hydroforming, and laser forming processes. Mehdi Salmani Tehrani received his PhD in 2007 from the Isfahan University of Technology in Iran, in Mechanical Engineering. He is currently a faculty member at the Isfahan University of Technology. His research interests mostly include stress and deformation analysis in solids and structures (especially in metal forming processes) and finite element simulation. Bernard F. Rolfe received his PhD in 2002 from the Australian National University in Australia on Inverse Modelling Metal Forming Processes. Currently, he is an Associate Professor at the Deakin University in Australia. He has published over 100 refereed articles. His current research focus is the forming of light weight structures, which includes the development of better material models for metal forming. He is the project leader of the AutoCRC's visionary project on lightweight automotive structures.Matthias Weiss received his PhD in 2007 from the Deakin University in Australia, in Material Sciences and Manufacturing. His current research focus is the development of advanced material models and testing methods to understand the effect of microstructure on formability, and to improve the r...