共查询到19条相似文献,搜索用时 62 毫秒
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长轴类花键挤压成形极限研究 总被引:4,自引:0,他引:4
建立了长轴类花键无约束正挤压的力学条件,采用等挤压比流动模型对矩形花键挤压进行了上限分析,讨论了变形程度、凹模型腔尺寸、齿形参数、摩擦因子等对无约束正挤压挤压相对应力及成形极限的影响,给出了花键挤压相对应力的经验公式,为正确制定挤压工艺提供了理论依据。 相似文献
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先介绍铝合金型材等温挤压工艺参数的确定方法,即先通过模具尺寸优化,实现型材挤出流度相等,再通过工艺参数优化,实现型材挤出温度相等;将得出的数据及曲线录入挤压工艺数据库管理系统以提高挤压生产线的自动化水平,进而提高产品质量。 相似文献
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本文利用上限基元技术对杯形件反挤压进行了上限分析,提出了一种优化的流动模型。对各对参数进行优化分析,得到了各种挤压比下的挤压力的最佳上限解,同时也给出了反挤稳定变形区的高度的最佳取值T与挤压比G的关系。计算结果通过实验得到验证,为反挤压杯形件的工艺制定,提供了有价值的依据。 相似文献
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In Part 1 of this series of papers, six kinematically admissible velocity fields, along with the power terms, were developed for use in upper bound models for arbitrarily shaped dies for axisymmetric extrusion. The three base velocity fields in the deformation zone were derived:
- (1) assuming proportional angles in the deformation zone,
- (2) assuming proportional areas in the deformation zone, or
- (3) assuming proportional distances from the centerline in the deformation zone.
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NUMERICAL DESIGN OF DIE LAND FOR SHAPE EXTRUSION 总被引:3,自引:0,他引:3
Hao Nanhai Department of Mechanical Engineering Taiyuan Heavy Machinery Institutex Li Kezhi Northwestern Polytechnical University 《机械工程学报(英文版)》2001,(1):91-93
0 INTRODUCTIONIntheextrusionofshapeswithflat faceddies ,asthebigdifferenceinsectionbetweentheextrudedshapeandthebillet ,theseriousfrictiononthematerial/toolinterface ,non uniformmetalflowispresentinthedeformationzone .Thismayresults ,dependingonthecomplexit… 相似文献
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W.A. Gordon C.J. Van Tyne Y.H. Moon 《International Journal of Mechanical Sciences》2007,49(1):104-115
In Part 1 of this series of papers, six kinematically admissible velocity fields, as well as the power terms, were developed for use in upper bound models for arbitrarily shaped dies for axisymmetric extrusion. Part 2 compared the results obtained in upper bound models for the six velocity fields through a spherical die shape and demonstrated that the sine-based velocity field was the best. In this final part, the application of the sine-1 field to extrusion through streamlined dies is developed. By fixing the values of two additional constants in the radial flow flexibility function, the two surfaces of velocity discontinuity, which separate the deformation zone from the incoming and outgoing material, will have no shear. In effect, the analysis for streamlined dies can be modeled without the surface of velocity discontinuity power terms. The results for an arbitrarily curved streamlined die, as proposed by Yang and Han, using the sine-1 velocity field and the cylindrical velocity field from the work by Yang and Han are compared. It is found that the upper bound model using the sine-1 velocity field predicts lower values for the extrusion pressure. A method to determine a streamlined die shape is proposed. The method allows flexibility between the entrance and exit by the use of a Legendre polynomial series for representation of the die surface. The method is termed an adaptable die design. The adaptable die design method is used to determine streamlined die shapes, which will minimize the pressure required for the extrusion process. 相似文献
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An adaptable die is one that not only produces the correct geometrical shape, but also is designed through an adaptable method to impart other desirable properties to the product or process. In this first part of a series of papers, six kinematically admissible velocity fields are developed for use in upper bound models for axisymmetric extrusion through various dies, including extrusion through adaptable dies. Three base velocity fields are presented:
- (1) assuming proportional angles in the deformation zone,
- (2) assuming proportional areas in the deformation zone, or
- (3) assuming proportional distances from the centerline in the deformation zone.
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Liu Haijiang Wan De'an Department of Mechanical Engineering Tongji University 《机械工程学报(英文版)》1999,12(4)
0 INTRODUCTIONFortheneedofthehighscientifictechnologydeveloping,producingtechnologynotonlyneedsaccuracyandrapidefficiency,butalsothemeasuringtechnologythatistheproducingtechnology’sbackingandguaranteeneedsthemorehighaccurcysoastogettheproductionhigh… 相似文献