For the free-bending forming of complex bending components, the forming limit significantly influences the complexity of the forming materials. In this study, the wrinkle factor Iw, which comprehensively affects the forming limit of free-bending, was obtained by theoretical analysis. The process parameters affecting the forming limit of free-bending were systematically studied by using the ABAQUS finite element simulation platform. Moreover, the effects of series of parameters on the relationship curve and wrinkling factor under different eccentricity conditions were also analyzed. The free-bending forming limit under the optimal conditions was obtained, which provides a process optimization method to improve the forming limit for practical test and production. Furthermore, the forming experiments were conducted on tubes with different wall thickness, and it was verified that the wall thickness factors significantly influenced the forming limit of the tubes. Finally, the forming experiments were carried out on 6061-T6 aluminum alloy, H2 copper, and H62 brass tubes. The results proved that the yield strength was the key material parameter affecting the forming limit of metal tubes.
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Tao Z, Fan X, Yang H, Ma J (2018) A modified Johnson-Cook model for NC warm bending of large diameter thin-walled Ti-6Al-4V tube in wide ranges of strain rates and temperatures. Trans Nonferrous Metals Soc China 28(2):298–308
Zhang H, Liu Y, Yang H (2017) Study on the ridge grooves deformation of double-ridged waveguide tube in rotary draw bending based on analytical and simulative methods. J Mater Process Technol 243:100–111
Murata M, Kuboki T (2015) CNC tube forming method for manufacturing flexibly and 3-dimensionally bent tubes. In: 60 Excellent Inventions in Metal Forming. Springer, Berlin Heidelberg, pp 363–368
Xiong H, Ma Y, Zhou S, He Y, Yang X, Jin K, Wang H, Luo X, Guo X (2018) Free bending forming technology of three dimensional complex axis hollow component. J Plasticity Eng 25(1):100–110
Beulich N, Craighero P, Volk W (2017) FEA simulation of free-bending- a preforming step in the hydroforming process chain. J Phys Conf Ser 896
Zhou Y, Li P, Li M, Wang L, Sun S (2018) Residual stress and springback analysis for 304 stainless steel tubes in flexible-bending process. Int J Adv Manuf Technol 94(1–3):1317–1325
Guo X, Jin K, Wang H, Pei W, Ma F, Tao J (2016) Numerical simulations and experiments on fabricating bend pipes by push bending with local induction-heating process. Int J Adv Manuf Technol 84(9):2689–2695
Wu J, Zhang Z, Shang Q, Li F, Wang Y, Hui Y, Fan H (2017) A method for investigating the springback behavior of 3D tubes. Int J Mech Sci 131-132:191–204
Guo X, Xiong H, Li H, Xu Y, Ma Z, El-Aty A, Ma Y, Jin K (2018) Forming characteristics of tube free-bending with small bending radii based on a new spherical connection. Int J Mach Tool Manu 133:74–82
Gantner P, Bauer H, Harrison D, Silva A (2005) Free-bending—a new bending technique in the hydroforming process chain. J Mater Process Technol 167:302–308
Guo X, Xiong H, Xu Y, El-Aty A, Ma Y, Zhao Y, Zhang S (2018) U-R relationship prediction method for aluminum alloy circular tube free-bending process based on sensitivity analysis of material parameters. Int J Adv Manuf Technol 99(5–8):1967–1977
Gantner P, Harrison D, Silva A, Bauer H (2007) The development of a simulation model and the determination of the die control data for the free-bending technique. P I Mech Eng B-J Eng 221(2):163–171
Murata M, Ohashi N, Suzuki H (1989) New flexible penetration bending of a tube : 1st report, a study of MOS bending method. Trans Japan Soc Mech Eng C 55:2488–2492
Guo X, Ma Y, Chen W, Xiong H, Xu Y, El-Aty A, Jin K (2018) Simulation and experimental research of the free bending process of a spatial tube. J Mater Process Technol 255:137–149
Murata M (1996) Effects of inclination of die and material of circular tube in MOS bending method. Trans Japan Soc Mech Eng 62(601):3669–3675
Murata M (1996) Analysis of circular tube bending by MOS bending method. Proc. 5th ICTP :505-508
Li P, Wang L, Li M (2016) Flexible-bending of profiles and tubes of continuous varying radii. Int J Adv Manuf Technol 88(5–8):1–7
Huang K, Lu M, Xue M (1988) Theory of thin shells. Higher Education Press
Yang H, Lin Y (2004) Wrinkling analysis for forming limit of tube bending processes. J Mater Process Technol 152(3):363–369
Li H, Yang H, Zhan M (2009) A study on plastic wrinkling in thin-walled tube bending via an energy-based wrinkling prediction model. Model Simul Mater Sc 17(17):35007–35039
Peek R (2002) Wrinkling of tubes in bending from finite strain three-dimensional continuum theory. Int J Solids Struct 39(3):709–723
Kawasumi S, Takeda Y, Matsuura D (2014) Precise pipe-bending by 3-RPSR parallel mechanism considering springback and clearances at dies. Transactions of the Japan Society of Mechanical Engineers 80:TRANS0343-TRANS0343
Guo X, Xiong H, Xu Y, Ma Y, El-Aty A, Tao J, Jin K (2018) Free-bending process characteristics and forming process design of copper tubular components. Int J Adv Manuf Technol 96(9–12):3585–3601
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Wei, W., Wang, H., Xiong, H. et al. Research on influencing factors and laws of free-bending forming limit of tube. Int J Adv Manuf Technol 106, 1421–1430 (2020) doi:10.1007/s00170-019-04692-0
- Forming limit
- Wrinkle factor
- Process parameters
- Material parameter