超高强钢多道次辊弯成形回弹规律研究
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摘要
超高强钢由于材料强度高、塑性较差等特点,成形难度也比普通钢更大,易发生回弹,是影响辊弯成形精度的重要原因。采用试验及有限元模拟的方法,对回弹规律及产生机理进行研究。设计三组道次数不同的辊弯成形试验,从成形角度、道次数、弯角增量等方面阐明回弹角度的变化规律。建立超高强钢辊弯成形的有限元仿真模型,分析V型件的成形特性,重点分析总应变、塑性应变和弹性应变在板材横向的分布,阐述辊弯成形回弹角度变化规律的产生机理。结果表明,对于单道次辊弯成形,随成形角度增大,回弹角度呈先增大后减小的变化趋势,弹性应变峰值的变化是回弹角度发生改变的主要原因;对于多道次辊弯成形,增多道次数有利于提高塑性变形量的积累、减小弹性应变峰值,这种多道次增量成形是辊弯成形所特有的工艺特性;增大弯角增量使板材弯角处厚度减薄,促进角部材料流动,有效减小了回弹量。对超高强钢多道次辊弯成形回弹规律进行了系统的阐述和研究,为减小回弹、提高成形精度提供了理论依据。
The forming difficulty of ultra high strength steel is greater than that of ordinary steel because of the high strength and poorplasticity of ultra high strength steel. Further, ultra high strength steel is prone to springback, which is an important factor influencingthe roll forming accuracy. An investigation of the springback law and its production mechanism using experiments and finite elementsimulation is introduced. Three sets of roll forming experiments with different numbers of stands are designed. The variation law ofthe springback angle is elucidated in terms of the forming angle, number of stages, increment angle, and so on. The finite elementsimulation model of roll forming of ultra high strength steel is established. The forming characteristics of V-shaped sheets areanalysed. The distribution of the total strain, plastic strain, and elastic strain in the transverse direction of the sheet are analysed. Themechanism of the variation of the springback angle in roll forming is discussed. The results show that for single-stand roll forming,the springback angle first increases and then decreases with increasing forming angle. The change in the elastic strain peak is the mainreason for the variation of the springback angle. For multi-stand roll forming, increasing the number of stands is conducive toincreasing the accumulation of plastic deformation and reducing the elastic strain peak. This multi-stand incremental forming is aunique process characteristic of roll forming; increasing the increment angle reduces the thickness of the sheet, promotes materialflow in the forming zone, and effectively reduces the springback. The systematic investigation of the springback law of multi-standroll forming provides a theoretical basis for reducing the springback and improving the forming accuracy.
The forming difficulty of ultra high strength steel is greater than that of ordinary steel because of the high strength and poorplasticity of ultra high strength steel. Further, ultra high strength steel is prone to springback, which is an important factor influencingthe roll forming accuracy. An investigation of the springback law and its production mechanism using experiments and finite elementsimulation is introduced. Three sets of roll forming experiments with different numbers of stands are designed. The variation law ofthe springback angle is elucidated in terms of the forming angle, number of stages, increment angle, and so on. The finite elementsimulation model of roll forming of ultra high strength steel is established. The forming characteristics of V-shaped sheets areanalysed. The distribution of the total strain, plastic strain, and elastic strain in the transverse direction of the sheet are analysed. Themechanism of the variation of the springback angle in roll forming is discussed. The results show that for single-stand roll forming,the springback angle first increases and then decreases with increasing forming angle. The change in the elastic strain peak is the mainreason for the variation of the springback angle. For multi-stand roll forming, increasing the number of stands is conducive toincreasing the accumulation of plastic deformation and reducing the elastic strain peak. This multi-stand incremental forming is aunique process characteristic of roll forming; increasing the increment angle reduces the thickness of the sheet, promotes materialflow in the forming zone, and effectively reduces the springback. The systematic investigation of the springback law of multi-standroll forming provides a theoretical basis for reducing the springback and improving the forming accuracy.
引文
[1]韩飞,刘继英,艾正青,等.辊弯成型技术理论及应用研究现状[J].塑性工程学报,2010,17(5):71-78.HAN Fei,LIU Jiying,AI Zhengqing,et al.State of the art of resrarch on roll forming process[J].Journal of Plasticity Engineering,2010,17(5):71-78.
[2]TRAUB T,CHEN Xin,GROCHE P.Experimental and numerical investigation of the bending zone in roll forming[J].International Journal of Mechanical Sciences,2017,131-132:956-970.
[3]BADR O M,ROLFE B,WEISS M.Effect of the forming method on part shape quality in cold roll forming high strength Ti-6Al-4V sheet[J]Journal of Manufacturing Processes,2018,4(32):513-521.
[4]WEIBENGA J H,WEISS M,ROLFE B,et al.Product defect compensation by robust optimization of a cold roll forming process[J].Journal of Materials Processing Technology,2013(213):978-986.
[5]韩飞,牛丽丽,王允,等.超高强钢辊弯成形回弹机理分析及控制研究[J].机械工程学报,2018,54(2):131-137.HAN Fei,NIU Lili,WANG yun,et al.Mechanism analysis and control research on springback of super high strength steel roll forming[J].Journal of Materials Processing Technology,2018,54(2):131-137.
[6]CRUTZEN Y,BOMAN R,PAPELEUX L,et al.Continuous roll forming including in-line welding and post-cut within an ALE formalism[J].Finite Elements in Analysis and Design,2018,143:11-31.
[7]ABVABI A,ROLFE B,HODGSON P D,et al.The influence of residual stress on a roll forming process[J].International Journal of Mechanical Sciences,2015,101-102:124-136.
[8]余海燕,王友.一种基于Chaboche理论的混合硬化模型及其在回弹仿真中的应用[J].机械工程学报,2015,51(16):127-134.YU Haiyan,WANG You.A combined hardening model based on Chaboche theory and its application in the springback simulation[J].Journal of Mechanical Engineering,2015,51(16):127-134.
[9]YU Haiyan.Variation of elastic modulus during plastic deformation and its influence on springback[J].Materials&Design,2009,3(30):846-850.
[10]LIU Xiaoli,CAO Jianguo,CHAI Xueting,et al.Investigation of forming parameters on springback for ultra high strength steel considering Young’s modulus variation in cold roll forming[J].Journal of Manufacturing Processes,2017,29:289-297.
[11]刘晓立,曹建国,柴雪婷,等.变弹性模量对高强钢辊弯成型回弹预测的影响[J]哈尔滨工业大学学报2018,7(50):1-7.LIU Xiaoli,CAO Jianguo,CHAI Xueting,et al.Effect of variable elastic modulus on springback prediction of high strength steel roll forming[J].Journal of Harbin Institute of Technology,2017,29:289-297.
[12]HAN Fei,AI Zhengqing,LIU Jiying,et al.Robust Optimization design of ultra high strength steel roll forming based on response surface method[J].Applied Mechanics and Materials,2010,20-23:1416-1422.
[13]ZENG Guo.Optimization design of roll profiles for cold roll forming based on response surface method[J].Materials and Design,2009(30):1930-1938.
[14]PANTHI S K,RAMAKRISHNAN N,AHMED M,et al.Finite element analysis of sheet metal bending process to predict the springback[J].Materials&Design,2010,31(2):657-662.
[2]TRAUB T,CHEN Xin,GROCHE P.Experimental and numerical investigation of the bending zone in roll forming[J].International Journal of Mechanical Sciences,2017,131-132:956-970.
[3]BADR O M,ROLFE B,WEISS M.Effect of the forming method on part shape quality in cold roll forming high strength Ti-6Al-4V sheet[J]Journal of Manufacturing Processes,2018,4(32):513-521.
[4]WEIBENGA J H,WEISS M,ROLFE B,et al.Product defect compensation by robust optimization of a cold roll forming process[J].Journal of Materials Processing Technology,2013(213):978-986.
[5]韩飞,牛丽丽,王允,等.超高强钢辊弯成形回弹机理分析及控制研究[J].机械工程学报,2018,54(2):131-137.HAN Fei,NIU Lili,WANG yun,et al.Mechanism analysis and control research on springback of super high strength steel roll forming[J].Journal of Materials Processing Technology,2018,54(2):131-137.
[6]CRUTZEN Y,BOMAN R,PAPELEUX L,et al.Continuous roll forming including in-line welding and post-cut within an ALE formalism[J].Finite Elements in Analysis and Design,2018,143:11-31.
[7]ABVABI A,ROLFE B,HODGSON P D,et al.The influence of residual stress on a roll forming process[J].International Journal of Mechanical Sciences,2015,101-102:124-136.
[8]余海燕,王友.一种基于Chaboche理论的混合硬化模型及其在回弹仿真中的应用[J].机械工程学报,2015,51(16):127-134.YU Haiyan,WANG You.A combined hardening model based on Chaboche theory and its application in the springback simulation[J].Journal of Mechanical Engineering,2015,51(16):127-134.
[9]YU Haiyan.Variation of elastic modulus during plastic deformation and its influence on springback[J].Materials&Design,2009,3(30):846-850.
[10]LIU Xiaoli,CAO Jianguo,CHAI Xueting,et al.Investigation of forming parameters on springback for ultra high strength steel considering Young’s modulus variation in cold roll forming[J].Journal of Manufacturing Processes,2017,29:289-297.
[11]刘晓立,曹建国,柴雪婷,等.变弹性模量对高强钢辊弯成型回弹预测的影响[J]哈尔滨工业大学学报2018,7(50):1-7.LIU Xiaoli,CAO Jianguo,CHAI Xueting,et al.Effect of variable elastic modulus on springback prediction of high strength steel roll forming[J].Journal of Harbin Institute of Technology,2017,29:289-297.
[12]HAN Fei,AI Zhengqing,LIU Jiying,et al.Robust Optimization design of ultra high strength steel roll forming based on response surface method[J].Applied Mechanics and Materials,2010,20-23:1416-1422.
[13]ZENG Guo.Optimization design of roll profiles for cold roll forming based on response surface method[J].Materials and Design,2009(30):1930-1938.
[14]PANTHI S K,RAMAKRISHNAN N,AHMED M,et al.Finite element analysis of sheet metal bending process to predict the springback[J].Materials&Design,2010,31(2):657-662.