板材成形回弹补偿与模具型面设计方法的研究
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摘要
板材冲压成形是一种先进、优质、高产、低消耗、低成本的加工工艺方法,在汽车,飞机,仪器仪表等工业领域有着广泛的应用。但由于板材成形是一个同时包括几何非线性、材料非线性和边界条件等问题的复杂的弹塑性大变形的力学过程,由此成形过程中必然伴随着多种缺陷如:板材破裂、起皱、回弹等。
回弹是板材成形常见的缺陷,并且一直没有较好的解决,为提高冲压件的产品质量,缩短新产品的开发周期,必须对回弹加以控制。由此本文提出了一种带有回弹补偿的模具型面设计的理论解析法,并数值模拟验证此方法具有良好的计算精度。
针对板材非圆弧弯曲回弹补偿模具型面的求解问题,本文提出了定弧长结构离散法,将非圆弧弯曲板材离散为若干微板元,并在经典圆弧弯曲回弹理论基础上推导出板材圆弧弯曲回弹前曲率求解公式,结合此公式及每段微板元上节点已知信息构造三次多项式插值,在MATLAB中迭代计算出零件回弹前形状曲线,法向偏置此曲线即可得到回弹补偿模具形状曲线。
为了检验此理论解析法是否满足工程需要,本文在第五章中利用ANSYS/LS-DYNA以第三章中设计的回弹补偿模具进行板材动态冲压、回弹数值模拟,获得零件模拟后形状曲线,在UG中与零件实际形状曲线进行比较,分析了两曲线间最大法向误差。
经过分析验证得出结论:此方法可根据非圆弧零件实际性状,直接而准确的求得回弹补偿模具型面,因此不仅极大消除了回弹缺陷而且大大减少了设计及实际中反复试模、修模工作量,并降低了冲压件的制造成本、缩短了新产品的开发周期。
最后,针对于板材冲压成形的破裂、起皱等其它缺陷,本文在Dynaform中结合某汽车覆盖件的冲压仿真阐述了成形模拟的过程,并深入探讨了如何根据模拟结果预测成形缺陷并进行工艺修正以消除此缺陷。
The sheet metal stamping forming is an advanced, highquality, efficient, low consumption and low cost manufacture technology, and is widely applied in automobile, aircraft, electronic instrument and other industries. But because sheet metal forming is a complicated elastic and plastic mechanical process with large deformation, which includes non-liner problem of geometry, material models and boundary conditions, so there are lots of defects in the forming process, for instance: sheet metal's rupture, wrinkle and springback, etc.
Spingback is one of the common defects in sheet metal forming, and have not been solved yet. In order to improve quality of forming parts and reduce production cycle, springback must be controled. A theoretical-analytical method of die's surface designing compensating springback is proposed in this paper.
The dispersing method by constant arc length to solve die's surface compensating springback of varied curvature bending for sheet metal is proposed, after that the sheet metal is dispersed as lots of infinitesimal cells. Based on classical theory about springback of arc curvature bending, the formula of bending curvature before springback in elastic-plastic arc bending is derived. Cubic polynomial interpolation is established, combining this formula with nodes' information of every infinitesimal cell, and then part's shape before springback is described by iterative calculation in MATLAB, finally the punch and die's figure compensating springback are gained by offsetting this curve.
In order to test if this theoretical-analytical method can meet engineering need, dynamic stamping forming numerical simulation with the die compensating springback designed in Chapter 3 by ANSYS/LS-DYNA is carried in Chapter 4, and then after implicit analysis of springback, part's shape curve is finally gained. Compare with part's true shape in UG, the maximal normal diviation of this two curves is analyzed.
By a train of analysis and demonstration, a conclusion can be reached: die's surface compensating springback can be directly gained by this method based on part's ture shape of varied curvature bending, and this method is directly and exactly to solve die's surface with springback compensation. It can not only eliminate springback largely, but also reduce the work to trial and repair die, cut cost and shorten the development cycle of new products.
At last, in order to reduce crack, wrinkle and other defects, stamping forming simulation of an automobile covering panel is carried based on Dynaform to expound the processes of simulation and discuss how to forecast defects and do modification to eliminate these defects.
回弹是板材成形常见的缺陷,并且一直没有较好的解决,为提高冲压件的产品质量,缩短新产品的开发周期,必须对回弹加以控制。由此本文提出了一种带有回弹补偿的模具型面设计的理论解析法,并数值模拟验证此方法具有良好的计算精度。
针对板材非圆弧弯曲回弹补偿模具型面的求解问题,本文提出了定弧长结构离散法,将非圆弧弯曲板材离散为若干微板元,并在经典圆弧弯曲回弹理论基础上推导出板材圆弧弯曲回弹前曲率求解公式,结合此公式及每段微板元上节点已知信息构造三次多项式插值,在MATLAB中迭代计算出零件回弹前形状曲线,法向偏置此曲线即可得到回弹补偿模具形状曲线。
为了检验此理论解析法是否满足工程需要,本文在第五章中利用ANSYS/LS-DYNA以第三章中设计的回弹补偿模具进行板材动态冲压、回弹数值模拟,获得零件模拟后形状曲线,在UG中与零件实际形状曲线进行比较,分析了两曲线间最大法向误差。
经过分析验证得出结论:此方法可根据非圆弧零件实际性状,直接而准确的求得回弹补偿模具型面,因此不仅极大消除了回弹缺陷而且大大减少了设计及实际中反复试模、修模工作量,并降低了冲压件的制造成本、缩短了新产品的开发周期。
最后,针对于板材冲压成形的破裂、起皱等其它缺陷,本文在Dynaform中结合某汽车覆盖件的冲压仿真阐述了成形模拟的过程,并深入探讨了如何根据模拟结果预测成形缺陷并进行工艺修正以消除此缺陷。
The sheet metal stamping forming is an advanced, highquality, efficient, low consumption and low cost manufacture technology, and is widely applied in automobile, aircraft, electronic instrument and other industries. But because sheet metal forming is a complicated elastic and plastic mechanical process with large deformation, which includes non-liner problem of geometry, material models and boundary conditions, so there are lots of defects in the forming process, for instance: sheet metal's rupture, wrinkle and springback, etc.
Spingback is one of the common defects in sheet metal forming, and have not been solved yet. In order to improve quality of forming parts and reduce production cycle, springback must be controled. A theoretical-analytical method of die's surface designing compensating springback is proposed in this paper.
The dispersing method by constant arc length to solve die's surface compensating springback of varied curvature bending for sheet metal is proposed, after that the sheet metal is dispersed as lots of infinitesimal cells. Based on classical theory about springback of arc curvature bending, the formula of bending curvature before springback in elastic-plastic arc bending is derived. Cubic polynomial interpolation is established, combining this formula with nodes' information of every infinitesimal cell, and then part's shape before springback is described by iterative calculation in MATLAB, finally the punch and die's figure compensating springback are gained by offsetting this curve.
In order to test if this theoretical-analytical method can meet engineering need, dynamic stamping forming numerical simulation with the die compensating springback designed in Chapter 3 by ANSYS/LS-DYNA is carried in Chapter 4, and then after implicit analysis of springback, part's shape curve is finally gained. Compare with part's true shape in UG, the maximal normal diviation of this two curves is analyzed.
By a train of analysis and demonstration, a conclusion can be reached: die's surface compensating springback can be directly gained by this method based on part's ture shape of varied curvature bending, and this method is directly and exactly to solve die's surface with springback compensation. It can not only eliminate springback largely, but also reduce the work to trial and repair die, cut cost and shorten the development cycle of new products.
At last, in order to reduce crack, wrinkle and other defects, stamping forming simulation of an automobile covering panel is carried based on Dynaform to expound the processes of simulation and discuss how to forecast defects and do modification to eliminate these defects.
引文
[1]翁克索夫,W约翰逊,工藤英明.金属塑性变形理论.北京:机械工业出版社,1992.
[2]包向军,蒋宏范等.轿车车门内板冲压成形计算机仿真.金属成形工艺,2000,(4):19-20.
[3]钟志华,李光耀.薄板冲压成形过程的计算机仿真与应用.北京:北京理工大学出版社,1998.
[4]余同希,章亮炽.塑性弯曲理论及其应用.北京:科学出版社,1992.
[5]宋黎,杨坚,黄天泽.板料弯曲成形的回弹分析与工程控制综述.锻压技术,1996,(1):18-22.
[6]王柏龄.铝车身的设计与发展.第十一届全国汽车车身制造技术研讨会论文,1999,5.
[7]张志勤,王先进.我国汽车用钢板的现状和发展.汽车技术,1998,17(1):26-29.
[8]张晓静,周贤宾.冲压加工技术最新进展.南昌:江西高校出版社,1998:200-205.
[9]余同希,章亮炽.塑性弯曲理论及其应用.北京:科学出版社,1992.
[10]Crandall S H.Discussion of Gardiner's paper[J].Tans.ASME,1957,79(8):7-8.
[11]Queener C A,DeAngelis R J.Elastic springback and residual stresses in sheet metal formed by bending[J].ASM Transactions,1968,61(10):757-768.
[12]秦志国,江乐新,韩鹏彪.塑性弯曲回弹理论的探讨[J].锻压技术,1995,21(1):28-32.
[13]赵彦启,闵乃燕,杨青春.直角形弯曲的变形分析与回弹计算[J].塑性工程学报,1996,3(1):38-43.
[14]黄春峰.弯曲弹性回弹及其工艺技术控制方法[J].模具技术,1998,(6):65-74.
[15]王晓林,周贤宾.金属板弹塑性非圆弧弯曲回弹的计算[J].塑性工程学报,1996,3(4):27-33.
[16]刘金武,贺永祥.理想弹塑性材料弯曲回弹分析及回弹弯矩计算[J].金属成形工艺,2001,19(3):22-25.
[17]张立玲.管材塑性弯曲回弹量计算[J].锻压技术,2002,27(3):37-39.
[18]Hill R.The Mathematical Theory of Plasticity M].London:Oxford University Press,1950.
[19]Mindlin R D.Influence of rotary inertia and shear on flexural motions of isotrop ic elastic plates[J].J.Appl.Mech,1951,8(18):31-38.
[20]AhmodS.Analysis of thick and thin shell structure by curved finite element[J].Int.J.Num.Meths.Engrg,1970,8(2):419-451.
[21]Ogawa H,Makinouchi A.Development of an elastoplastic FE code for accurate prediction of springback in sheet bending processes and It's validation by experim ents[A].Progress in Computational Analysis of Inelast Strutures[C],International centre for theoretical physics,1993:1641-1646.
[22]Ghouati O,Joannic D,Gelin J C.Optimization of process parameters for the control of springback in deep drawing[A].NUM IFORM'98[C],1998:819-824.
[23]FinnM J,Galbraith P C.Use of a coupled explicit- implicit solver for calculting springback in automotive body panels[J].Journa I of Materials Processing Technology,1995.
[24]Zhong Z H.Finite element procedures for contact-Impact problems[M].Oxford University Press,1993.
[25]Belytschko T.Contact-impact by the pinball algorithm with penalty and lagrangian methods[J]. Int.J.Numer.Methods Engneering,1991,15(31):547-572.
[26]郑莹,吴勇国,李尚健,李志刚,肖景容.板料成形数值模拟进展[J].塑性工程学报,1996,3(4):34-47.
[27]孟会林,孙新利,王少龙.板料冲压成形和回弹分析过程的三维动态模拟[J].金属成形工艺,2002,20(5):15-20.
[28]栗振斌.数控弯管回弹的有限元数值模拟预测与补偿研究[D].兰州:西北工业大学出版社,2004.
[29]Paulsen F,Welo T.Application of numerical simulation in the bending of aluminium-alloy profiles [J].Jouranl of Materials Processing Technology,1996,13(58):274-285.
[30]邵鹏飞,王秀喜,车玫.板料成形中的回弹计算和模具修正[J].机械强度,2001,23(2):187-189.
[31]武晓红.板料弯曲回弹的机理分析及减小回弹的措施[J].模具技术,2002,(5):47-58.
[32]李继领,刘效春.弯曲成形件影响回弹的几种策略[J].煤矿机械,2004,(3):57-58.
[33]范志明.弯曲回弹的减少与消除.现代机械,2003,8(5):36-37.
[34]Webb RD,Hardt D E.A transfer function description of sheet metal forming for process control.Trans ASM E,J.Engerring Industry,1991,33(2):44-52.
[35]F.Lan,J.Chen,J.Linb.A method of constructing smooth tool surfaces for FE prediction of springback in sheet metal forming.Journal of Materials Processing Technology,2006,5(177):382-385.
[36]Jiang Dan,Wang Lancheng.Direct generation of die surfaces from measured data points based on springback compensation.Int J Adv Manuf Technol,2006,11(31):574-579.
[37]Huang W H,Chang L,Kao P W,Chang C P.Effect of die angle on deformation texture of copper processed by equal channel angular extrusion[J].Materials Science and Engineering,2001,307(1-2):113-181.
[38]胡世光,陈鹤峥.板料冷压成型原理(修订版).北京:国防工业出版社,1989.
[39]刘国庆,杨庆东.ANSYS工程应用教程—机械篇.北京:中国铁道出版社,2003.
[40]苏荣华,梁冰.结构仿真分析—ANSYS应用.沈阳:东北大学出版社,2005.
[41]刘相新,孟宪颐.ANSYS基础与应用教程.北京:科学出版社,2006.
[42]周宁.ANSYS机械工程应用实例.北京:中国水利水电出版社,2006.
[43]尚晓江,邱峰,赵海峰,李文颖.ANSYS结构有限元分析方法与范例应用.北京:中国水利水电出版社,2006.
[44]尚晓江,苏建宇.ANSYS/LS-DYNA动力分析方法与工程实例.北京:中国水利水电出版社,2006.
[45]W Y D Yuen.Springback in the Strech-Bending of Sheet Metal With Non-Uniform Deformation.Journal of Materal Technology,1990,5(22):1-20.
[46]Mai Huang,James C Gerdeen.springback of doubly curved developable sheet metal.Surface-An Overview.SAE,1994,22(8):718-731.
[47]雷正保.汽车覆盖件冲压成形CAE技术及其工业应用研究:(博士学位论文)杭州:中南大学,2003.
[48]王成,邵敏.有限单元法基本原理和数值方法.北京:清华大学出版社,1997.
[49]R Hill.Mathematical Theory of Plasticity.Oxford University Press,1966.
[50]陆明万,张雄,葛东云.工程弹性力学与有限元法.北京:清华大学出版社,2005.
[51]Makinouchi,Nakamachi,Onata Wagoner R H.2nd International Conference on Numerical Simulation of 3-D Sheet Metal Forming Proeesses(NumiSheet'93).Isehara Japan,1993.
[52]何涛,杨竞等.ANSYS/LS-DYNA非线性有限元分析实例指导教程.北京:机械工业出版社,2007.
[53]霍同如,徐秉业.板料成形的计算机辅助工程系统.力学进展,1996,(4):548-557.
[54]胡轶敏.车身覆盖件冲压成形的三维仿真与试验研究:(博士学位论文).上海:上海交通大学,1999.
[55]肖大志.薄板压缩起皱的模拟研究.重庆钢铁高等专科学校学报,1995,10(2):17-23.
[56]Sawada T.Shell analysis on surafce defction of sheet metal.Proceeding of Advanced Technology of Plasticity,1990,11(43).
[57]崔令江.薄板冲压成形中的剪应力起皱的研究:(博士学位论文).哈尔滨:哈尔滨工业大学,1989.
[58]包向军,蒋宏范,何丹农等.材料参数对汽车覆盖件冲压成形性能影响的数值模拟[J].机械工程材料,2001,25(7):17-19.
[2]包向军,蒋宏范等.轿车车门内板冲压成形计算机仿真.金属成形工艺,2000,(4):19-20.
[3]钟志华,李光耀.薄板冲压成形过程的计算机仿真与应用.北京:北京理工大学出版社,1998.
[4]余同希,章亮炽.塑性弯曲理论及其应用.北京:科学出版社,1992.
[5]宋黎,杨坚,黄天泽.板料弯曲成形的回弹分析与工程控制综述.锻压技术,1996,(1):18-22.
[6]王柏龄.铝车身的设计与发展.第十一届全国汽车车身制造技术研讨会论文,1999,5.
[7]张志勤,王先进.我国汽车用钢板的现状和发展.汽车技术,1998,17(1):26-29.
[8]张晓静,周贤宾.冲压加工技术最新进展.南昌:江西高校出版社,1998:200-205.
[9]余同希,章亮炽.塑性弯曲理论及其应用.北京:科学出版社,1992.
[10]Crandall S H.Discussion of Gardiner's paper[J].Tans.ASME,1957,79(8):7-8.
[11]Queener C A,DeAngelis R J.Elastic springback and residual stresses in sheet metal formed by bending[J].ASM Transactions,1968,61(10):757-768.
[12]秦志国,江乐新,韩鹏彪.塑性弯曲回弹理论的探讨[J].锻压技术,1995,21(1):28-32.
[13]赵彦启,闵乃燕,杨青春.直角形弯曲的变形分析与回弹计算[J].塑性工程学报,1996,3(1):38-43.
[14]黄春峰.弯曲弹性回弹及其工艺技术控制方法[J].模具技术,1998,(6):65-74.
[15]王晓林,周贤宾.金属板弹塑性非圆弧弯曲回弹的计算[J].塑性工程学报,1996,3(4):27-33.
[16]刘金武,贺永祥.理想弹塑性材料弯曲回弹分析及回弹弯矩计算[J].金属成形工艺,2001,19(3):22-25.
[17]张立玲.管材塑性弯曲回弹量计算[J].锻压技术,2002,27(3):37-39.
[18]Hill R.The Mathematical Theory of Plasticity M].London:Oxford University Press,1950.
[19]Mindlin R D.Influence of rotary inertia and shear on flexural motions of isotrop ic elastic plates[J].J.Appl.Mech,1951,8(18):31-38.
[20]AhmodS.Analysis of thick and thin shell structure by curved finite element[J].Int.J.Num.Meths.Engrg,1970,8(2):419-451.
[21]Ogawa H,Makinouchi A.Development of an elastoplastic FE code for accurate prediction of springback in sheet bending processes and It's validation by experim ents[A].Progress in Computational Analysis of Inelast Strutures[C],International centre for theoretical physics,1993:1641-1646.
[22]Ghouati O,Joannic D,Gelin J C.Optimization of process parameters for the control of springback in deep drawing[A].NUM IFORM'98[C],1998:819-824.
[23]FinnM J,Galbraith P C.Use of a coupled explicit- implicit solver for calculting springback in automotive body panels[J].Journa I of Materials Processing Technology,1995.
[24]Zhong Z H.Finite element procedures for contact-Impact problems[M].Oxford University Press,1993.
[25]Belytschko T.Contact-impact by the pinball algorithm with penalty and lagrangian methods[J]. Int.J.Numer.Methods Engneering,1991,15(31):547-572.
[26]郑莹,吴勇国,李尚健,李志刚,肖景容.板料成形数值模拟进展[J].塑性工程学报,1996,3(4):34-47.
[27]孟会林,孙新利,王少龙.板料冲压成形和回弹分析过程的三维动态模拟[J].金属成形工艺,2002,20(5):15-20.
[28]栗振斌.数控弯管回弹的有限元数值模拟预测与补偿研究[D].兰州:西北工业大学出版社,2004.
[29]Paulsen F,Welo T.Application of numerical simulation in the bending of aluminium-alloy profiles [J].Jouranl of Materials Processing Technology,1996,13(58):274-285.
[30]邵鹏飞,王秀喜,车玫.板料成形中的回弹计算和模具修正[J].机械强度,2001,23(2):187-189.
[31]武晓红.板料弯曲回弹的机理分析及减小回弹的措施[J].模具技术,2002,(5):47-58.
[32]李继领,刘效春.弯曲成形件影响回弹的几种策略[J].煤矿机械,2004,(3):57-58.
[33]范志明.弯曲回弹的减少与消除.现代机械,2003,8(5):36-37.
[34]Webb RD,Hardt D E.A transfer function description of sheet metal forming for process control.Trans ASM E,J.Engerring Industry,1991,33(2):44-52.
[35]F.Lan,J.Chen,J.Linb.A method of constructing smooth tool surfaces for FE prediction of springback in sheet metal forming.Journal of Materials Processing Technology,2006,5(177):382-385.
[36]Jiang Dan,Wang Lancheng.Direct generation of die surfaces from measured data points based on springback compensation.Int J Adv Manuf Technol,2006,11(31):574-579.
[37]Huang W H,Chang L,Kao P W,Chang C P.Effect of die angle on deformation texture of copper processed by equal channel angular extrusion[J].Materials Science and Engineering,2001,307(1-2):113-181.
[38]胡世光,陈鹤峥.板料冷压成型原理(修订版).北京:国防工业出版社,1989.
[39]刘国庆,杨庆东.ANSYS工程应用教程—机械篇.北京:中国铁道出版社,2003.
[40]苏荣华,梁冰.结构仿真分析—ANSYS应用.沈阳:东北大学出版社,2005.
[41]刘相新,孟宪颐.ANSYS基础与应用教程.北京:科学出版社,2006.
[42]周宁.ANSYS机械工程应用实例.北京:中国水利水电出版社,2006.
[43]尚晓江,邱峰,赵海峰,李文颖.ANSYS结构有限元分析方法与范例应用.北京:中国水利水电出版社,2006.
[44]尚晓江,苏建宇.ANSYS/LS-DYNA动力分析方法与工程实例.北京:中国水利水电出版社,2006.
[45]W Y D Yuen.Springback in the Strech-Bending of Sheet Metal With Non-Uniform Deformation.Journal of Materal Technology,1990,5(22):1-20.
[46]Mai Huang,James C Gerdeen.springback of doubly curved developable sheet metal.Surface-An Overview.SAE,1994,22(8):718-731.
[47]雷正保.汽车覆盖件冲压成形CAE技术及其工业应用研究:(博士学位论文)杭州:中南大学,2003.
[48]王成,邵敏.有限单元法基本原理和数值方法.北京:清华大学出版社,1997.
[49]R Hill.Mathematical Theory of Plasticity.Oxford University Press,1966.
[50]陆明万,张雄,葛东云.工程弹性力学与有限元法.北京:清华大学出版社,2005.
[51]Makinouchi,Nakamachi,Onata Wagoner R H.2nd International Conference on Numerical Simulation of 3-D Sheet Metal Forming Proeesses(NumiSheet'93).Isehara Japan,1993.
[52]何涛,杨竞等.ANSYS/LS-DYNA非线性有限元分析实例指导教程.北京:机械工业出版社,2007.
[53]霍同如,徐秉业.板料成形的计算机辅助工程系统.力学进展,1996,(4):548-557.
[54]胡轶敏.车身覆盖件冲压成形的三维仿真与试验研究:(博士学位论文).上海:上海交通大学,1999.
[55]肖大志.薄板压缩起皱的模拟研究.重庆钢铁高等专科学校学报,1995,10(2):17-23.
[56]Sawada T.Shell analysis on surafce defction of sheet metal.Proceeding of Advanced Technology of Plasticity,1990,11(43).
[57]崔令江.薄板冲压成形中的剪应力起皱的研究:(博士学位论文).哈尔滨:哈尔滨工业大学,1989.
[58]包向军,蒋宏范,何丹农等.材料参数对汽车覆盖件冲压成形性能影响的数值模拟[J].机械工程材料,2001,25(7):17-19.