摘要
对于铝合金挤压成形而言,凹模型腔轮廓设计是挤压工艺设计中一个重要方面。不适当的凹模型腔轮廓设计会导致过多的材料内部剪切,模口附近金属流动方向急剧变化以及材料挤出速度不均匀等现象的发生。因此,为了控制金属流动,保证模具的应力、应变分布均匀,减小挤压力,需要对凹模型腔轮廓设计进行研究分析。
本文运用上限法建立铝合金棒材挤压成形的流动模型,推导了坯料在五种不同曲线型腔模具中变形时的动可容速度场、应变速率场及上限功率的表达式。同时,以挤压力最小为优化目标,对成形过程进行优化,获得最低能耗下的型腔曲线长度。为验证上限解的可靠性,对最佳型腔曲线长度下棒材成形过程进行二维有限元数值模拟,得到了挤压力与型腔曲线表面接触应力的分布曲线,数值解与理论解相吻合。
引入流函数法和保角映射方法,完成了凹模型腔曲面的数学描述,并建立了铝合金壁板扁挤压筒挤压模型。在此基础上,综合考虑型线长度、定径带长度、摩擦因子、挤压速度和型腔形状这五个因素,通过三维有限元模拟,获得了各种不同因素组合下的挤压力以及凹模在该挤压过程中所受到的最大等效应力等信息。从而得出最优的挤压工艺参数与模具设计参数的组合,实现了对铝合金壁板挤压的优化设计。
本文的研究成果对于完善铝合金挤压模具设计理论具有一定的指导意义。
During the aluminum alloy forming process, die cavity surface design is very important. If the die cavity surface shape is improper, the shearing force will be increased, the direction of metal flow near the die outlet will change rapidly, and the metal flow velocity will not be uniform. In order to avoid these problems and reduce the die pressure, the design of a suitable die cavity surface seems to be necessary.
An extrusion flow model of aluminum alloy cylinder is built by the upper-bound method, the kinematically admissible velocity field, the strain rate field and the deformation power are deduced with five different die containers. In addition, aiming at reducing the extrusion power, the length of the die containers is optimized. FEM is used to simulate the extrusion process with the best die container length, and then the distribution of extrusion power and die contact stress are obtained. It can be seen that the theoretical results are in good accordance with the simulation results. The results show, with the best die container length and the same area reduction ratio, the third-order polynomial die and the cosine die are the best amongst the profiles considered.
The mathematic function of die cavity surface is established, and the model for aluminum alloy flat-plate extrusion is constructed. Based on this, the extrusion power and maximum equivalent stress are obtained by using FEM. During this process, some related factors are considered, including die cavity surface length, die calibrating strap length, friction factor, extrusion speed and die cavity surface shape. As a result, the optimal design for aluminum alloy flat extrusion is achieved, and from which the optimum parameters of extrusion process and die design are got.
The research results have great signification in improving the extruding die design theory for aluminum alloy.
引文
[1] 潘复生,张丁非.铝合金及应用[M].北京:化学工业出版社,2006.1
[2] 刘静安.铝型材挤压模具设计、制造、使用及维修[M].北京:冶金工业出版社,1999.10
[3] 黄成华.铝合金圆棒挤压模拟研究.东北大学硕士学位论文[D],2006.2
[4] 赵云路,唐志玉.铝塑型材挤压成形技术[M].北京:机械工业出版社,2000.9:1~2
[5] 郑军,傅建等.铝型材挤压模具优化设计现状和趋势[J].四川工业学院学报,2003,22(1):73~75
[6] 黄克坚,包忠诩.关于挤压变形规律理论研究方法的一些探讨[J].塑性工程学报,2003,10(4):45-48
[7] 蔡微,柳瑞清.高温挤压变形的模拟实验研究[J].锻压技术,1999(1):7~9
[8] 顾迎新,陈淑利.空心铝型材挤压成形过程的有限元数值模拟[J].沈阳大学学报,2004,16(2):36~37
[9] 刘全坤,许在文,王美芹等.扁挤压筒应力的光弹性与有限元分析[J].中国机械工程,2005,16(9):839~843
[10] 马立安.铝型材挤压模具参数优化及关键技术的研究[D].山东大学硕士学位论文,2002.10
[11] O. C. Zienkiewicz, J. Z. Zhu. A Simple Error Estimator and Adaptive for Practical Engineering Analysis[J]. Int. J. Numer. Meth. Engng., 1987, 24(6): 337~357
[12] O. C. Zienkiewicz, Y. C. Liu, G. C. Huang. Error Estimation and Adaptivity in Flow Formulation for Forming Problems[J]. Int. J. Numer. Meth. Engng., 1988, 25(3): 423~442
[13] C. K. Lee, S. H. Lo. An Automatic Adaptive Refinement Finite Element Procedure for 2D Elatostatic Analysis[J]. Int. J. Numer. Meth. Engng., 1992, 35(10): 1967~1989
[14] J. E. Bas, Van Rens. Finite Element Simulation of the Aluminum Extrusion Process: Shape Prediction for Complex Profiles[J]. Technology University of Eindhoven PhD thesis, 1993
[15] K.Park, D. Y. Yang. Mismatching Refinement with Domain Decomposition for the Analysis of Steady-state Metal Forming Process Accepted for Publication[J]. Int. J. Numer. Meth. Engng, 1999, 35(11): 1245~1256
[16] Hyun-Woo,Shin, Dong-Won, Kim, Naksoo Kim. A simplified threedimensional finite-element analysis of the non-axisymmetrie extrusion processes[J]. Journal of Materials Processing Technology, 1993, 38(3): 567~587
[17] 于沪平,彭颖红,阮雪榆.平面分流焊合模成型过程的数值模拟[J].锻压技术,1999,24(5):9~11
[18] 周飞,彭颖红,阮雪榆.铝型材挤压过程有限元数值模拟[J].中国有色金属学报,1998,8(4):637~642
[19] 闫洪,夏巨谌,包忠诩等.型材挤压模工作带长度设计计算的数学建模[J].塑性工程学报,2002,9(1):70~73
[20] Hong Yan, Juchen Xia. An approach to the optimal design of technological parameters in the profile extrusion process[J]. Science and Technology of Advanced Materials, 2006, 7(1): 127~131
[21] 刘汉武,丁桦,崔建忠.铝型材挤压分流组合模有限元分析与计算[J].模具工业,1999(4):9~11
[22] 闫洪,包忠诩.型材挤压过程三维弹塑性有限元模拟[J].轻合金加工技术,2000,28(11):30~33
[23] Sheppard T, Nisaratanaporn E, McShane H B. Material flow and pressure prediction when extruding through bridge dies[J]. Zeitschrift fuer Metallkunde/Materials Research and Advanced Techniques, 1998,89(5): 327~337
[24] 冷艳.铝棒材等温挤压技术的研究.北方工业大学硕士学位论文[D],2003.5
[25] 张君,杨合等.基于有限元技术的大型6061无缝管挤压温度变化规律研究[J].重型机械,2004(5):40~45
[26] Wu Xianghong, Zhao Guoqun, Luan Yiguo. Numerical simulation and die structure optimization of an aluminum rectangular hollow pipe extrusion process[J]. Materials Science and Engineering, 2006, 435~436(5): 266~274
[27] 林高用,陈兴科,蒋杰等.铝型材挤压模工作带优化[J].中国有色金属学报,2006,16(4):561~566
[28] Zou Lin, Xia Ju-Chen, Hu Guo-An. Optimizing of aluminum sections extrusion die based on BP neural network[J]. Journal of Plasticity Engineering, 2003, 10(2): 42
[29] Vadim L.Berezhnoy. Friction-assisted extrusion as an alternative to the indirect and direct extrusion of hard aluminum alloys[J]. Light Metal Age, 1997, 55(3~4): 8~13
[30] Saha.Pradip K. Thermodynamics and tribology in aluminum extrusion[J]. Wear, 1998, 218(2): 179~190
[31] M. Schikorra, L. Donati, L. Tomesani b. The role of friction in the extrusion of AA6060 aluminum alloy,process analysis and monitoring[J]. Journal of Materials Processing Technology, 2007(191): 288~292
[32] S.H.Kim, S.W.Chung, S.Padmanaban. Investigation of lubrication effect on the backward extrusion of thin-walled rectangular aluminum case with large aspect ratio[J]. Journal of Materials Processing Technology, 2006, 180(1~3): 185~192
[33] Huang,Guang-Fa, Lin,Gao-Yong, Jiang,Jic. Numerical simulation of extrusion process of aluminum profile with large extrusion ratio[J]. Zhongguo Youse Jinshu Xuebao/Chincsc Journal of Nonferrous Metals, 2006, 16(5): 887~893
[34] 吴向红,赵国群,马新武等.模具锥角对铝材挤压过程影响规律的研究[J].特种成形,2005(5):75~78
[35] 陈泽中,娄臻亮等.复杂铝型材挤压成形有限体积仿真[J].上海交通大学学报,2005,39(1):27~31
[36] 中国模具设计大典编委会.中国模具设计大典[M].南昌:江西科学技术出版社,2003.1:439
[37] Ales Mihelic, Boris Stok. Tool design optimization in extrusion process[J]. Computers and Structures, 1998(68): 283~293
[38] 邹琳,夏巨谌等.挤压模具型腔轮廊曲线优化拟合分析[J].锻压技术,2002(6):51~54
[39] 陈维民,詹艳然.挤压过程的数值模拟及锥角优化[J].中国机械工程,1994,5(4):12~14
[40] 王富耻,张朝晖,李树奎.不同型线凹模钨合金静液挤压过程数值仿真研究[J].兵工学报,2001,22(4):525~528
[41] 赵德文,王晓文,刘相华.轴对称冲入半无限体的参量积分解法[J].应用科学学报,2003,21(2):161~165
[42] N.Venkata Reddy, P.M.Dixit, G..K.Lal. Die design for axisymmetric extrusion[J]. Journal of materials processing technology, 1994(55): 332~339
[43] 黄克坚,包忠诩,黄志超.型材宽展挤压的数值仿真[J].模具工业,2005(3):53~58
[44] 李国俊,张治民,李旭.大变形零件温挤压凹模型孔设计技巧[J].轻合金加工技术,2005,33(9):27~30
[45] 温景林.金属挤压与拉拔工艺学[M].沈阳:东北大学出版社,1996.12:45
[46] 贾俐俐,高锦张.实心铝型材挤压导流模应用研究[J].塑性工程学报,2000,7(2):66~69
[47] 冯秋红.组合式扁挤压筒的结构优化设计.合肥工业大学硕士学位论文[D],2006.3:18~19
[48] 于沪平,阮雪榆,李绍林.墩挤复合变形力的理论解[J].模具技术,1998(2):15~19
[49] 汪大年.金属塑性成形原理[M].北京:机械工程出版社,1986.11
[50] 赵志业.金属塑性加工力学[M].北京:冶金工业出版社,1987.3
[51] 徐慧,郭胜利等.两种坐标系下上限法求解棒材挤压变形力的对比研究[J].重型机械,2006(1):17~21
[52] B.艾维超.金属成形工艺与分析[M].北京:国防工业出版社,1988.9
[53] 滕宏春,林桂霞.带有动芯轴的管料壁厚减薄缩口成形的理论解析[J].机械工程学报,2005(7):1~10
[54] #12
[55] W.A.Gordon, C.J.Van Tyne, Y.H.Moon. Axisymmetric extrusion through adaptable dies-Part3: Minimum pressure streamlined die shapes[J]. International Journal of Mechanical Sciences, 2007, 47: 104~115
[56] 施晓红,周佳.精通GUI图形界面编程[M].北京:北京大学出版社,2003.1
[57] 王家文,王皓等.MATLAB7.0编程基础[M].北京:机械工程出版社,2005.7
[58] 王祝堂,田荣璋.铝合金及其加工手册[M].湖南:中南工业大学出版社,1989
[59] 刘斌,王敏杰,刘耀中.面向数值优化设计的挤出模参数化建模方法[J].模具工业,2003(1):17~19
[60] 贾俐俐.多边形截面工件挤压的上限研究.合肥工业大学硕士学位论文[D],1988.3:11~13
[61] 刘斌,王敏杰,刘耀中.流线型挤出模参数化建模方法研究[J].中国塑料,2003,17(8):83~87
[62] 数学弹性力学中的几个基本问题[M].北京:科学出版社,1958.2
[63] #12
[64] 胡龙飞,刘全坤,冯秋红.基于共形映射的壁板型材挤压模具型腔建模研究机械工程学报[J].已录用
[65] 高锦张,贾俐俐.宽截面铝型材挤压导流模应用研究[J].东南大学学报,2000,30(2):97~100
[66] 赵云路,刘静安.实心铝型材挤压模具优化设计(2)[J].轻合金加工技术 1997,25(6):38~42
[67] 温景林.金属挤压与拉拔工艺学[M].沈阳:东北大学出版社,2003.8
[68] 邓小民,孙中建等.铝合金挤压时的摩擦与摩擦因数[J].中国有色金属学报,2003,13(3):599~605
[69] 闫洪,夏巨谌,李志刚等.工艺参数对铝型材挤压变形规律的影响[J].中国有色金属学报,2002,12(6):1154~1160
[70] 黄克坚,包忠诩,周天瑞.有限体积数值模拟技术在型材挤压变形规律研究中的运用[J].轻合金加工技术,2003,31(4):29~31
[71] 颜建辉,柳瑞清.正确选择铝型材挤压速度的方法[J].轻合金加工技术,2002,30(7):36~37
[72] 吴贵生.试验设计与数据处理[M].北京:冶金工业出版社,1997.1
[73] 唐乃梅.基于响应面法的膜结构截面优化及其在MSC.Nastran上的二次开发[D].北京工业大学硕士学位论文,2005.5