用户名: 密码: 验证码:
板材多点成形中起皱和回弹的数值分析
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
多点成形技术是金属板材三维自由曲面成形的一种柔性加工方法,其基
    本思想是将传统的整体模具离散化,由一系列规则排列的基本体(或称冲
    头)组成的“柔性多点模具”来代替,由基本体球头的包络曲面来完成板材
    成形。多点成形技术作为一种新兴的技术已在飞机、船舶、汽车等诸多制造
    领域有着广泛的应用前景。
    无压边多点成形通常用于变形量不大的曲面成形,是板材多点成形过程
    中使用频率很高的一种成形方法。多点成形在成形变形量不大的曲面时,通
    常不压边,这样既可省去切边工序又可以节省材料,另一方面又能简化多点
    压机结构,降低其造价。由于没有压边圈,板材面内变形力较小,主要以面
    外弯曲变形为主,导致在多点成形中起皱缺陷更容易出现,特别是在薄板多
    点成形中,起皱是工艺上必须克服的成形缺陷。
    由于没有压边圈的作用,板材成形过程中,回弹对成形件最终形状的影
    响要比有压边时大。影响回弹的因素很多,如板材厚度,板材的材质以及成
    形件变形量的大小等。本文采用数值模拟技术对多点成形过程的回弹进行了
    分析,另外还探讨了典型零件在多点成形时,通过控制基本体群成形面形状
    消除回弹的方法。
    1. 板材无压边多点成形的起皱数值模拟
    采用显式算法进形起皱数值模拟时,板材必须离散成足够小的有限元单
    元,使皱纹能够已相当小的波长正确的模拟出来。通过不同尺寸有限元单元
    的数值结果比较,建立了板材无压边起皱分析的有限元模型。对双向曲率曲
    面—球面和马鞍面进行了详细的数值模拟,研究了板材厚度、曲率半径以及
    材质等对起皱的影响。板厚与变形程度是影响起皱的重要因素,增大板材厚
     71
    
    
    吉林大学硕士研究生学位论文
    度,减小成形件曲率半径均可有效的抑制起皱的产生;文中对 08AL 和 L2Y2
    铝两种不同材料的板材成形球面和马鞍面的起皱现象进行了有限元分析。结
    果表明选用具有较大的弹性模量的 08AL较具有较小弹性模量的 L2Y2 不容
    易产生起皱缺陷。
     通过对多点成形过程中的起皱产生过程的分析,发现在无压边多点成形
    中,起皱主要产生于基本体对板材的不完全约束,在成形后期起皱出现最大
    值,在成形结束时,部分皱纹被压平。基于对多种不同板厚、不同曲率半径
    的球面和马鞍面成形件的数值分析,得到了球面与马鞍面无压边、不起皱多
    点成形极限图。在本文之前,还没有多点成形不起皱极限图方面的结果。
     2. 板材无压边多点成形的回弹数值模拟。
     完整的板材成形包括加载和卸载两个过程。本文建立了采用显-隐式算法
    模拟回弹问题的有限元模型。即采用动态显式算法模拟板材成形过程,采用
    隐式算法模拟卸载回弹过程。这种方法克服了显式算法耗时大,难以收敛的
    缺点,解决了隐式算法不能处理好接触问题的缺点,极大的提高了回弹数值
    的计算效率,具有实用性和高效性的特点。
     主要分析了板材厚度、成形件变形量以及材质等对柱面、球面及马鞍面
    的无压边多点成形的回弹影响,并且利用中心插分法,拟合出成形件回弹
    前、后曲面形状,计算出回弹量的大小。由数值模拟结果可以看出,在多点
    成形中,板材厚度越小,变形量越小,卸载后回弹越大,反之,厚度越大,
    变形量越大则回弹越小。
     3. 多点成形过程中成形面的修正与回弹控制的研究
     利用数值模拟技术,在回弹分析的基础上,给出了基于回弹数值计算的
    柱面、球面多点成形基本体群成形面的修正方法。对于目标曲率半径为的圆
    柱面,但板厚为 1.0mm时,经过三次修正,形状总体误差只有 0.0044m;板
    厚为 1.5mm时,经过五次修正,形状误差达到 0.00083m;对于目标曲率半径
    为 1200mm,板厚为 1.5mm时,经过两次修正形状误差达到 0.0962m;依据
    最后一次修正的成形面调整基本体群的形状进形多点成形,可以有效的补偿
    板回弹影响。实现板材的一次精确成形,提高产品的成形精度。这些结果对
    多点成形技术的进一步工程应用具有一定的参考价值和实际意义
Multi-point forming(MPF) is a flexible manufacturing technology for three
    dimensional sheet metal forming. In multi-point forming, the conventional solid die
    is replaced by “flexible Multi-point die” composed by a series of discrete elements
    (or punches). The forming process of sheet metal is implemented by the envelope
    surface of punches. Multi-point Forming can be applied extensively in a lot of
    fields such as aircraft, stream and navel ships, vehicle, large sculpture and modern
    architecture etc.
     Sheet metal forming in MPF without blank holder, which is a common
    process method, is usually applied in processing those kinds of surface parts which
    have not big deformation amount. In this process condition, the original material
    consuming and the press cost can be reduced to a low level as well as simplifying
    the press structure and leaving out trimming procedure in metal sheet forming
    process. without blank holder, the deformation inside the surface is distinctly
    smaller than the bending outside the surface. Wrinkle is a key factor to determine
    whether the part could be formed and become one of primary forming defects
    especially for thin metal sheet in MPF.
     On the other hand, in this condition, springback was more serious than those
    forming with blank holder. Springback was affected by numerous factors, such as
    thickness of metal sheet, material property and deformation amount and so on. And
    the last content of this paper was to research the springback eleminating method
    through controlling the forming surface of the elements group for metal sheet in
    multi-point forming process.
    1.Numerical simulation of wrinkling in multi-point forming for
    metal sheet without blank holder
     As view from mechanics, wrinkle is a kind of plastic ?in metal sheet surface.
    It is more difficult with static implicit algorithm than dynamic explicit in analyzing
     73
    
    
    吉林大学硕士研究生学位论文
    wrinkling problem. Based on the explicit algorithm, there must be offered as fine
    element as to make the wrinkle to simulate with adequate small wavelength.
     Obtained the numerical simulation results of wrinkle with different size of
    finite element, establishing the finite element model for wrinkling numerical
    analysis. The Multi-point forming process of sphere, saddle surface of different
    materials with different thickness and deformations were simulated, and those
    results show that metal sheet thickness, deformation and material property have
    effect on wrinkle defect. With metal sheet thickness increasing, deformation
    diminishing, wrinkle can be gradually weakened. Simultaneously, wrinkle was
    affected by material property too. In this paper, two material, 08Al steel and L2Y2
    pure aluminum are simulated, and found L2Y2 pure aluminum are more sensitive
    to wrinkling than 08AL steel because the Elastic modulus of 08AL is greater than
    that of L2Y2.
     In this paper, the wrinkling growing up process was also analyzed, and
    discovered that wrinkling in multi-point forming for metal sheet without blank
    holder, derives from metal sheet under an half-baked restraining which comes from
    the elements group. The maximal of wrinkle depth appear in the anaphase of the
    forming processing, and some wrinkle can be planished at the end of forming. In
    addition, the non-wrinkling limit of sphere and saddle surface were obtained.
    2. Numerical simulation of springback in multi-point forming for
    metal sheet without blank holder
     There were included loading and unloading course in an intact metal sheet
    forming. Based on explicit-implicit algorithm, the finite element model for
    numerical simulation of springback was established. Dynamic-explicit formulation
    was employed to analyze the loading process and implicit formulation to unloading
    process. This method not only overcomes the time consuming and convergence
    problem in explicit algorithm but also avoids the contact difficult in implicit
    algorithm, with go
引文
1. 李明哲,中村敬一. 基本的な成形原理の检讨(板材多点成形法の研究 第 1 报).平成
     4 年度塑性加工春季讲演会论文集, 1992, 519~522
    2. M. Z. Li, Z. Y. Cai, Z. Sui, Q.G. Yan. Multi-point forming technology for sheet metal,
     Journal of Materials Processing Technology, 2002, 129(1-3):333~338
    3. O.C.Zikiwicz, S.valliappa and I.P. King. Elastic-plastic simlations of engineering
     problems “initial stress” finite element approach. Intenatioal Joural for umerical methods
     in engineering,1969, 1:75~100
    4. P.V.Marcal. Large strain, large displacement analysis on finite element methods in
     continuum mechanics. edited by J.T.Ode and E.R.de Arantes, The University of Alabama
     in Huntsville press, 1973, 535~561
    5. Y.Yamada, N.Yoshimura and T.Sakurai. Plastic stress –strain matrix and its application
     for the solution of elastic-plastic problems by the finite element method. Int, J.Mech, Sci.,
     1968, 10:343~54
    6. Y.Yamada, T.Kawai, N.Yoshimura and T.Sakura. Analysis of the elastic-plastic problem
     by the matrix displacement method, Proceedings of the second conferece of matrix
     methods in structural mechanics. Wright-Parrerso Air Force Base, Ohio, 1969, 1271~1299
    7. O.C.Zikiwicz ad P.N.Godole. Flow of plastic and viso-plastic solids with special referece
     to extrusion and formig processes. In, Joul, METH, Eng.,1974,8:3~16
    8. O.C.Zikiwicz, and P.N.Godole. A penalty function approach to problems of plastic flow
     of metals with large surface deforomations. J.Strain analysis,1975 ansysis, 1975,
     10:180~183
    9. N.M.Wang. A rigid-plastic rate-sensitive finite element analysis of hydrostatical
     processes . Pro.um Analysis Form, EdPiftma JFT, O.C.Zikiwicz et al.Joh Wiley and
     SONS. 1984:117~164
    10. C.H.Lee and S.Kobayashi. New solution to rigid-plastic deformation problem using
     matrix method. Trans.ASME, J.Engng.Ind., 1973,7:865~873
    11. Iseki H, Jimma T. Finite element method of ansysis of the hydrostatic bulging of a sheet
     metal. Bulletin of the JSME, 17, 1974, 112:1240~1246
    12. Wifi A .S. An incremental complete solution of the stretch-forming and deep-drawing of a
     circular blank using a hemispherical punch. Int .J.Mech.Sci ., 1976, 18:105~110
    13. Kobayashi S.Kim J.H. Deformation ansysis of axisymmetric sheet formig processes by
     rigid-plastic finite elemt method. In :Koistinen D.P.Wang, N.M (eds). Plenum Press, 1978:
     367~391
    14. Wang N.M., Wenner M, L. Elastic-viscoplastic ansysis of simple stretching forming
     processes. In: Koistinen D.P.Wang n.m (eds). Mechanics of sheet metal Forming.Plenum
     Press, 1978:367~391
    62
    
    
    参考文献
    15. E.Onate & O.C.Zienkiewicz. A viscous shell formulation for the analysis of thin sheet
     metal forming. Int, J.Mech, Sci, 1983, Vol.25:158~163
    16. C.H.Lee & S.Kobayashi. New solution to rigid-plastic of deformation problems using a
     matrix method. Trans.ASME, J, Engr, Ind. 1973,Vol., 95:210~214
    17. S.Kobayashi & j.h.Kin. Deformation axisymmetric sheet forming processes by the rigid-
     plastic finite element method. In: D.P.Koisthen & N.M.Wang (eds), Mechanics of sheet
     Metal Forming, Prenum Press, New York, 1978,54~58
    18. N.M.Wang. A rigid-plastic rate sensitive finite element method for modeling sheet metal
     forming processes. In: N.M.Wang & S.S.Tang (eds), Computer Modeling of Sheet
     Forming Processes, AIME, 1985:78~81
    19. P.V.Marcal & I.P.King. Elastic-plastic analysis of two-dimentional systems by the finite
     element method. Int.J.Mech.Sci, 1967, Vol, 9:96~100
    20. Y.Yamada et al. Plastic stress-strain matrix and its Application for the solution of elastic-
     plastic problems by the finite element method. Int.J.Mech. Sci, 1968, Vol, 10:5~10
    21. H.D.Hibbit et al. A finite element formulation for problems of large strain and large
     displacement. Int, J.Solids Structurews, 1970, Vol, 6:112~118
    22. J.R.Osias et al. Finite elastic-plastic deformation. In: Int.J.Solids Structures, 1974, Vol, 10
    23. R.M.McMeeking & J.R.Rice. Finite Element formulation for Problems of Large Elastic-
     plastic Deformation. Int. J.Structures, 1975, Vol.11:179~183
    24. Wang, N. M. Budiansky, B. Analysis of sheet metal stamping by a finite-element method.
     In: Mathematical Techiques Finite Element Method, 1978,vol 45(3): 73~82
    25. A.S.Wifi. An increamental complete solution of the Stretch-dorming and Deep-drawing of
     a Circular Blank Using a Hemispherical unch. Int, J. Mech. Sci., 1976, Vol, 18:86~91
    26. B.S.Anderson. A numerical study of the deep drawing processes. In J.F.T.Pittman et
     al.(eds), Proc. Numerical Methodsin Industrial Forming Processses, Pineridge, Swansea,
     1982, 709~721
    27. A.Makinouchi. Elastic-plastic stress analysis of bending and hemming of sheet metal. In;
     N.M.Wang&S.C.Tang (eds) Computer Model Forming Processes AIME, 1985, 161~176
    28. R.D.Mindlin. Influence of rotary inertia and shear on flexural motions of isotropic, Elastic
     Plates. J. Appl.Mech., 1951, 18:31~38
    29. T.Belytschko et al. Hourglass control in linear and nomlinear problems. Comput. Meths,
     Appl.Mech. Engrg. 1984, 43:251~276
    30. Wang.S.P, Nakamachi E. Nonlinear contact and friction modeling in dynamic explicit
     finite element ansysis. Numisheer’96, Dearborn, 1996,145~153
    31. Guo Y.Q.Batoz J.L.et al. Finite procedures for strain estimation of shet metal forming
     parts. Int.J.Num. Methods Eng., 1990, 30:1385~1401
    32. Chou.C.H.et al. Ansysis of sheet metal forming operations by a stress resultant constiutive
     law. Int. J.Numer Methods Eng., 1994, 37(5): 717~735
    33. Tang S.C.et. al. Quarsratatic ansysis of sheet metal forming processes a design evaluation
     tool.J.Mater . Process Technol., 1994, 45:261~266
    34. E.Harpell, C.Lamontagne, M.J.Worswick, P.Martin, M.Finn, &C.Galbraith. Deep drawing
     and stretching of Al 5754 sheet LS-DYNA3D simulation and validation. In: Proceedings
     63
    
    
    吉林大学硕士研究生学位论文
     of the 3rd International Conference: NUMISHEET’96 Numerical Simulation of 3-d Sheet
     Forming PROCESSES- Verification of Simulations with Experiments, J.K.Lee, Kinzel, &
     R.H.Wagoner (eds.), 386~393
    35. MARC-CDC. General purpose finite element analysis program. MARC analysis. Corp.
     Providence RI, 1990:196~202
    36. J.O.Halquist. DYNA2D An explicit finite element and finite different code for
     axisymmteric and plate strain calculation. Uiversity of California, Lawerence Livermore
     National Lab Rept,1989:215~221
    37. J.O.Hallquist, NIKE3D. An implicit, finite deformation, finite element code for ansyzling
     the static and dynamic response of three-dimensional solids. Uiversity of California,
     Lawrence Livermore National Laboratory, Rept. ICD-18822, EV. 1, 1984
    38. LS-NIKE3D User’s Manual Livermore Sofrware Technology Corporation ,1995
    39. Y.Nagai and K.Ito. An advance ansysis of axisymmteric plastic sheet banding include
     transverse shear deformation. Int.J.Mech.Sci., 1991, 33: 717~728
    40. M.Kawka and A.Makinouchi. Finite element simulation of sheet metal forming processes
     by processes. NUMIFORM’ 92, A.A.Balkemma, Rotterdam 1992, 491~496
    41. M.Kawka and A.Makinouchi. Shell-element formulation in the swtatic explicit FEM code
     for the simulation of sheet stamping. Joural of Materials Processing Technology, 1995,
     54(1-4): 105~115
    42. E.Nakamachi and A.Makinouchi. Development of process simulationm system for
     autobody panel forming by FE ansysis and laser atereolithography techniques. 17th
     Biennial Congress. IDDRG Congress Proc., 1992, 461~466
    43. A.Makinouchi, A.B.D.Santos and E.Nakamachi. Comparison of different contact
     description in finite element simulation of 3-Dsheet metal forming processes.
     MECAMAT’91,Teodosiu, Raphanel & Sidoroff (eds), Balkema, Rotterdam,1993,
     443~440
    44. K.Kassem, F.Fuchs, M.Hillmann et al. Mathematical modeling of the sheet metal forming
     process with INDEED. Num.Mech.in Industrial Forming processes, ED, Chont, Wood
     &Zienkiewicz, 1992, 461~466
    45. 李尧臣,金属板料冲压成形的有限元法模拟.力学学报,1995,27(3):351~364.
    46. Tang SC. Computer predictiong of the deformed sharp of a draw blank during the boinder
     –wrap stge. J.Appl.Metal working.1980, (3): 695~712
    47. 董相怀.轴对称其三维金属板料成形的有限元模拟. 武汉:华中理工大学,1992.
    48. 柳玉起.板料成形塑性流动规律及起皱破裂回弹的数值模拟研究.长春:吉林工业大
     学,1995:34~39
    49. Du CO, et al.. Springback predition in sheet forming simulation. SAE Trans.Section5,
     940937: 707~717
    50. Kawka M.Makinouchi A. Ansysis of multroperation automotive sheet metal forming
     processes. Advanceed Tech.of Plasticity. Proc.4th ITP, Beijing 1993, (ICTP’93),
     1811~1816
    64
    
    
    参考文献
    51. Toshihiko Kuwabara, Susumu Takahashi, Yohsuke Miyashita. 2-D Springback Analysis
     for Stretch-Bending Processes Based on Total Strain Theory. SAE International Congress
     and Exposition, Detroit, Michigan, 1995: 1~10
    52. 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
    53. N.He, R.HWayoner, Springback simulation in sheet metal forming.
     Nmuisheet’96
    54. N.Montmayeur.C.Staub. Springback prediction with Optris Numisheet’99,
     France, 1999
    55. Mattiasson. Kjell. Numerical results from large deflection beam and frame problems
     anlysed by means of elliptic integrals. Mathematical Techematical Techniques -Numerical
     Numerical Analysis, 1981, vol. 17:145~153
    56. Luc Papeleux, Lean-Philippe Ponthot. Finite element simulation of springback in sheet
     metal forming. In: Journal of Material Processing Technology, 2002, 125-126:785~791
    57. Volakan Esat, Haluk Darendeliler, Mustafa Ilhan Gokler. Finite element analysis of
     springback in bending of aluminiunm sheet. In: Materials and Design, 2002, 23: 223~229
    58. K.J. Bathe, R.Slavkovic and M.Kojic. On large strain elastic–plastic and creep analysis.
     Finite element methods for nonlinear problems. Europe–US Symposium, Trondheim,
     Norway, 1985, 175~190
    59. 蔡中义, 李明哲, 李湘吉. 板材成形回弹数值分析的静力隐式方法. 中国机械工程,
     2002,13(17): 1458~1461
    60. 李明哲, 李淑慧, 陈建军等. 板材多点成形不同工艺方法的数值模拟研究, 中国机械工
     程, 2000, 11(9): 1042~1046
    61. 张立力、戴映荣、齐恬. 数值模拟参数和工艺参数对板材成形回弹影响的研究. 锻压
     技术,2002 Vol.27 No.6:65~72
    62. Narkeeran Narasimhan, Michael Lovell. Predicting springback in sheet metal forming an
     explicit implicit sequential solution procedure. Finite Elements in Analysis and Design
     1999,33: 29~42
    63. W.D. Cardena, L.M. Genga, D.K. Matlockb. Measurement of springback. International
     Journal of Mechanical Sciences, 2002, 44: 79~101
    64. 李广权,板材无模多点成形过程数值模拟研究,吉林工业大学博士学位论文,1997
    65. 李广权,李明哲,苏世忠,李淑慧,刘纯国.板材多点成形时摩擦边界条件的处理
     方法,农业机械学报,1999,30(2):99~103
    66. 李广权,李达,李东平,李明哲.板材多点成形时复杂边界条件的研究. 哈尔滨工
     业大学学报,2000,32(5):75~77
    67. 李明哲,李广权,苏世忠,付沛福.板材多点成形时非连续性边界条件的处理. 农
     业机械学报,1997,28:85~89
    68. 蔡中义. 板材多点成形过程数值模拟与最优成形路径研究. 吉林大学博士学位论
     文,2000
     65
    
    
    吉林大学硕士研究生学位论文
    69. 李明哲,蔡中义,刘纯国.板材多点反复成形的残余应力分析. 机械工程学报,
     2000,36(1):50~54
    70. 蔡中义,李明哲,陈建军.板材多点成形隐式算法数值模拟专用软件及关键技术.哈
     尔滨工业大学学报,2000,32(4):82~88
    71. 蔡中义,李明哲,李广权.金属成形数值模拟中的接触单元法.中国机械工程,
     2000,11(8):933~935
    72. 蔡中义,李明哲,陈建军.板材多点成形隐式算法数值模拟专用软件及关键技术,
     哈尔滨工业大学学报,2000,32(4):82~88
    73. Cai Zhongyi, Li Mingzhe, Feng Zhaohua. Theory and method of optimum path forming
     for sheet metal. Chinese Journal of Aeronautics,2001,14(2):118~122
    74. 苏世忠.基于有限元多晶体弹塑模型模拟板材无模多点成形过程的研究.吉林大学博
     士学位论文,2000
    75. 苏世忠,李明哲,陈建军.有限元多晶体模型模拟铝板多点成形过程.哈尔滨工业大
     学学报,2000,32(4):117~119
    76. 李明哲,苏世忠,陈庆敏,付沛福.有限元多晶体模型预测不同加载方式对板条多
     点弯曲成形的影响.吉林工业大学学报自然科学学报,2000,30(3):25~29
    77. 李淑慧.板材多点成形工艺的有限元仿真研究.吉林工业大学博士学位论文,1999
    78. 李明哲,李淑惠,柳泽,陈建军,李广权.板材多点成形过程起皱现象数值模拟研
     究,中国机械工程.1998,9(10):34~38
    79. 李淑惠,李明哲,蔡中义,姚建国.板材多点弯曲过程及回弹现象的数值模拟.农业
     机械学报,2000,31(1):112~115
    80. 李明哲,李淑惠,柳泽,陈建军,李广权.板材多点成形过程起皱现象数值模拟研
     究.中国机械工程,1998,9(10):34~38
    81. 李淑惠,李明哲,蔡中义,姚建国.板材多点弯曲过程及回弹现象的数值模拟.农业
     机械学报,2000,31(1),112~115
    82. 李明哲,李淑惠,柳泽,陈建军,李广权.板材多点成形过程起皱现象数值模拟研
     究.中国机械工程,1998,9(10):34~38
    83. 李淑慧,李明哲,陈建军.板材多点分段成形工艺的数值模拟研究.机械工程学报,
     2000,36(8):88~91
    84. 李尚健,董湘怀.金属板材成形过程模拟.北京:机械工业出版社,1999
    85. E. Onate, J. Rojeck, CG. Garino, NUMISTAMP A research project for assessment of
     finite element models for stamp processes. Journal of Materials processing Technology,
     1995, 50(1): 17~38
    86. J.O. Hallquist D. J. Benson and G.L. Goudreau. Implementation of a modified Hughes-
     Liu shell into a fully vectorized explicit finite element code. Proc. of the International
     Symposium on Finite Element Methods for Nonlinear problems, Trondhiem, Norway,
     1985:310~318
    66
    
    
    参考文献
    87. M. Papadrakakis,A Method for the automated evaluation of the dynamic relaxation
     parameters,Computer Methods for Applied Mechanical Engineering, 1981(25):35~48
    88. P. Underwood, Dynamic relaxation, computational method for transient analysis, T.
     Belytschko, T.J.R. Hughes, Eds, 1986(1): 245~263
    89. 徐涛.数值计算方法.长春:吉林科学技术出版社,1998
     67

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700