Abstract：The limit bending-radius of tensile instability as the main straightening technical parameter, decides the structure of equipment and the quality of products for continuous straightening thin-walled tubes. However, it is usually carried out based on the experiential data and chart by skilled laborers, whose art is based on long experience and experiments. Therefore, by means of the membrane shell theory and it’s relevant hypothesis the normal strain and stress components were firstly obtained, and then the limit bending-radius model for the prediction of diffuse plastic instability under pure bending was presented using Swift’s criterion, finally the dynamic simulation was done by FEA. The results have shown that: the analytical model can be used to calculate the limit bending-radius of tensile instability for straightening thin-walled tubes correctly, which is decreased with the increase of the initial bending-radius, and it relates to the diameter and the metal plastics deformation capacity of the tube. The basis can be provided for optimizing straightening technical parameters and completing the theory of thin-walled tube straightening.
张子骞， 颜云辉， 杨会林， 王 雷. 薄壁管材连续矫直拉伸失稳极限弯曲半径模型[J]. 钢铁, 2014, 49(6): 53-58.
ZHANG Zi-qian， YAN Yun-hui， YANG Hui-lin， WANG Lei. Limit Bending-Radius Model of Tensile Instability for Continuous Straightening a Thin-Walled Tube. Iron and Steel, 2014, 49(6): 53-58.
张子骞，杨会林，田永利. 薄壁管材矫直过程应变中性层偏移模型与分析[J]，中国机械工程，2013，24(10)；1390-1395.Zhang Ziqian, Yang Yuilin, Tian Yongli. Offset Modeling and Analysis of Strain Neutral Surfaces for Straightening a Thin-walled Tube[J], China Mechanical Engineering, 2013, 24(10)：1390-1395.
[1]
张子骞，杨会林，田永利. 薄壁管材矫直过程应变中性层偏移模型与分析[J]，中国机械工程，2013，24(10)；1390-1395.Zhang Ziqian, Yang Yuilin, Tian Yongli. Offset Modeling and Analysis of Strain Neutral Surfaces for Straightening a Thin-walled Tube[J], China Mechanical Engineering, 2013, 24(10)：1390-1395.
[2]
张子骞，张柏森，杨会林，等. 管棒材等曲率矫直力模型可视化设计[J]. 东北大学学报(自然科学版)，2012，33(3)：409-413.ZHANG Ziqian, ZHANG Baisen, YANG Huilin, etal. The Visual Design On The Force Model Of Tubes And Bars Equal Curvature Straightening[J]. Journal of Northeastern University (Natural Science), 2012, 33(3)：409-413.
[2]
张子骞，张柏森，杨会林，等. 管棒材等曲率矫直力模型可视化设计[J]. 东北大学学报(自然科学版)，2012，33(3)：409-413.ZHANG Ziqian, ZHANG Baisen, YANG Huilin, etal. The Visual Design On The Force Model Of Tubes And Bars Equal Curvature Straightening[J]. Journal of Northeastern University (Natural Science), 2012, 33(3)：409-413.
[3]
S. Boria, S. Pettinari, F. Giannoni. Theoretical analysis on the collapse mechanisms of thin-walled composite tubes[J]. Composite Structures, 2013, 103: 43-49.
[3]
S. Boria, S. Pettinari, F. Giannoni. Theoretical analysis on the collapse mechanisms of thin-walled composite tubes[J]. Composite Structures, 2013, 103: 43-49.
[4]
H. Li, H. Yang, J. Yan, M. Zhan. Numerical study on deformation behaviors of thin-walled tube NC bending with large diameter and small bending radius[J]. Computational Materials Science, 2009, 45(4)：921-934.
[4]
H. Li, H. Yang, J. Yan, M. Zhan. Numerical study on deformation behaviors of thin-walled tube NC bending with large diameter and small bending radius[J]. Computational Materials Science, 2009, 45(4)：921-934.
[5]
A. Limam, L.-H. Lee, E. Corona, S. Kyriakides. Inelastic wrinkling and collapse of tubes under combined bending and internal pressure[J]. International Journal of Mechanical Sciences, 2010, 52(5)：637-647.
[5]
A. Limam, L.-H. Lee, E. Corona, S. Kyriakides. Inelastic wrinkling and collapse of tubes under combined bending and internal pressure[J]. International Journal of Mechanical Sciences, 2010, 52(5)：637-647.
[6]
G. Nefussi, A. Combescure. Coupled buckling and plastic instability for tube hydroforming[J]. International Journal of Mechanical Sciences, 2002, 44(5):899-914.
[6]
G. Nefussi, A. Combescure. Coupled buckling and plastic instability for tube hydroforming[J]. International Journal of Mechanical Sciences, 2002, 44(5):899-914.
[7]
Jeong Kim, Sang-Woo Kim, Woo-Jin Song, Beom-Soo Kang. Analytical approach to bursting in tube hydroforming using diffuse plastic instability[J]. International Journal of Mechanical Sciences,2004, 46(10); 1535-1547.
[7]
Jeong Kim, Sang-Woo Kim, Woo-Jin Song, Beom-Soo Kang. Analytical approach to bursting in tube hydroforming using diffuse plastic instability[J]. International Journal of Mechanical Sciences,2004, 46(10); 1535-1547.
[8]
Ramin Hashemi, Ahmad Assempour, Ehsan Masoumi Khalil Abad. Implementation of the forming limit stress diagram to obtain suitable load path in tube hydroforming considering M-K model[J]. Materials & Design, 2009, 30(9): 3545-3553.
[8]
Ramin Hashemi, Ahmad Assempour, Ehsan Masoumi Khalil Abad. Implementation of the forming limit stress diagram to obtain suitable load path in tube hydroforming considering M-K model[J]. Materials & Design, 2009, 30(9): 3545-3553.
[9]
Sansot Panich, Frédéric Barlat, Vitoon Uthaisangsuk, Surasak Suranuntchai, Suwat Jirathearanat. Experimental and theoretical formability analysis using strain and stress based forming limit diagram for advanced high strength steels[J]. Materials & Design, 2013,51: 756-766.
[9]
Sansot Panich, Frédéric Barlat, Vitoon Uthaisangsuk, Surasak Suranuntchai, Suwat Jirathearanat. Experimental and theoretical formability analysis using strain and stress based forming limit diagram for advanced high strength steels[J]. Materials & Design, 2013,51: 756-766.
[10]
Q.H. Bui, R. Bihamta, M. Guillot, G. D’Amours, A. Rahem, M. Fafard，Investigation of the formability limit of aluminium tubes drawn with variable wall thickness[J]. Journal of Materials Processing Technology, 2011, 211(3): 402-414.
[10]
Q.H. Bui, R. Bihamta, M. Guillot, G. D’Amours, A. Rahem, M. Fafard，Investigation of the formability limit of aluminium tubes drawn with variable wall thickness[J]. Journal of Materials Processing Technology, 2011, 211(3): 402-414.
[11]
Xianfeng Chen, Zhongqi Yu, Bo Hou, Shuhui Li, Zhongqin Lin. A theoretical and experimental study on forming limit diagram for a seamed tube hydroforming[J]. Journal of Materials Processing Technology, 2011,211(12) :2012-2021.
[11]
Xianfeng Chen, Zhongqi Yu, Bo Hou, Shuhui Li, Zhongqin Lin. A theoretical and experimental study on forming limit diagram for a seamed tube hydroforming[J]. Journal of Materials Processing Technology, 2011,211(12) :2012-2021.
[12]
Amir Hassannejadasl, Daniel E. Green, William J. Altenhof, Chris Maris, Murray Mason. Numerical modeling of multi-stage tube hydropiercing[J]. Materials & Design, 2013,46: 235-246.
[12]
Amir Hassannejadasl, Daniel E. Green, William J. Altenhof, Chris Maris, Murray Mason. Numerical modeling of multi-stage tube hydropiercing[J]. Materials & Design, 2013,46: 235-246.
[13]
ZHANG Ziqian, YAN Yunhui, YANG Huilin. A New Stress Mathematical Model Of Deformation Zone While Straightening Thin-Walled Tube[J]. Advanced Materials Researh, 2013, (653)：1488-1493.
[13]
ZHANG Ziqian, YAN Yunhui, YANG Huilin. A New Stress Mathematical Model Of Deformation Zone While Straightening Thin-Walled Tube[J]. Advanced Materials Researh, 2013, (653)：1488-1493.
[14]
梁炳文,胡世光.弹塑性稳定理论[M].北京:国防工业出版社,1983: 323-340.LIANG BingWen, HUShiGuang. Elastoplastic stability theory[M]. Bei jing: National Defense Industry Press, 1983: 325-340.
[14]
梁炳文,胡世光.弹塑性稳定理论[M].北京:国防工业出版社,1983: 323-340.LIANG BingWen, HUShiGuang. Elastoplastic stability theory[M]. Bei jing: National Defense Industry Press, 1983: 325-340.
2014, Vol. 49 
