超长圆锥管无芯模旋拉过程的有限元数值模拟

【作者】 陈平；

【导师】 贺地求；

【作者基本信息】 中南大学 ， 机械电子工程， 2003， 硕士

【摘要】 旋拉联合成形工艺是有色金属特种型材——超长无缝锥管的无芯模高效加工工艺，具有生产效率高、设备投资小、加工成本低、材料利用率高等特点。发达国家自80年代以来，大力发展这一新工艺和成套设备，现这种特种型材，尤其是铝合金质的，作为高杆(电杆、灯杆、旗杆等)用材，在城市和道路建设中得到了广泛的应用。我国在该方面的研究还处于落后状态，至今还没有形成一条旋拉生产线投入生产，另一方面，我国城市化进程和道路建设正方兴未艾，对这种铝型材存在巨大的需求，因此开发旋拉联合成形设备并研究其机理具有重要的理论和现实意义。 旋拉工艺的金属变形过程具备锻造、挤压、拉伸、弯曲、环轧和滚压等工艺的特点，变形区外部条件为无芯模、轴向拉拔力强化和旋轮接触加载，本文针对这些特点，运用弹塑性理论(Mises屈服准则、塑性流动定律、变分原理等)，利用ANSYS软件建立了无芯模旋拉过程的有限元模型。 无芯模旋拉过程是一个具有材料非线性、几何非线性和接触非线性的弹塑性变形过程，由此必须建立非线性控制方程，而非线性方程求解的关键是解决收敛性问题，因此如何设置影响收敛性的参数问题成为本文有限元模拟的难题。本文对程序经过反复的调试后，最终确定主要参数法向接触刚度因子FKN为模型收敛性主要影响因素，并确定FKN的最佳值，使无芯旋拉成形有限元模型收敛性问题得到了很好的解决。 无芯模旋拉过程的有限元模拟结果深入地揭示了旋拉工艺的变形特点： 1、旋拉加工具有典型的局部变形特点。 2、整个工件沿轴向伸长。 3、管坯在旋拉缩径的同时，壁厚有增厚的趋势。 本文进行的可旋性实验，其结果与有限元模拟的理论结果基本相符，有力地证明了本有限元模型和程序的正确性，以及本文结论的可靠性。更多还原

【Abstract】 Stretch Planishing and Drawing Combined Process (SPDCP) is a high efficient process technology of a non-mandril model for the extra long and non-seamed conical pipe-the nonferrous special type of profiled pipe. This technology has many characteristics such as high efficiency, small investment in equipments, lower machining cost and high efficient utilization of materials etc. Since 1980s, this new technology and its equipment have been developing in developed countries. Now, this special type of profiled pipe, especially the aluminium alloy profiled pipe has been used widely as high pole such as telegraph pole, lamp pole and flagpole etc in the city and road construction. On the one hand, the research on SPDCP in our country falls far behind developed countries, as yet there is even not a product line for Stretch Planishing and Drawing process. On the other hand, the urbanization progress and road construction are in the ascendant and there is a big demand for this alluminium alloy profiled pipe, so the development for Stretch Planishing and Drawing Combined equipment and the research on its mechanism has important theoretical and realistic significance,.In this paper, according to the characteristic of SPDCP, such as without mandril, the drawing force strengthened in the axial direction, contact loaded by rollers and so on , the theory of elastic-plastic(Mises yield criterion the flow theory of plasticity variation principle) and ANSYS have been applied to establish the FEM model of SPDCP without mandril.Stretch Planishing and Drawing Combined Process is a process of elastic-plastic deformation which has the following property: material non-linearity geometry non-linearity and contact non-linearity, therefore nonlinear equilibrium equations must be created Moreover, the key to solve non-linear equation is convergence, so the difficult problem of FEM simulation in this paper is how to set parameters which will influence convergence After repeating debug the ANSYS program, it is found that FKN is the main parameter which influences convergence, and finally the optimum value of FKN has been gained, which make the convergence problem of the FEM model of SPDCP without mandril has been well solved.The FEM simulation results of Stretch Planishing and Drawing Combined Process without mandril deeply disclosed the deformation characteristics of the SPDCP:1 There are typical local deformation characteristics in the SPDCP.2 The whole work-piece has elongated along the axial direction.3 The pipe’s thickness is prone to increase while the pipe’s diameters aredwindling away in the SPDCP.The results of the experiment involved in the paper basically accord with the FEM simulation ones, which pithily has proved that the FEM model and its program are correct and the conclusion drawn in the paper is credible更多还原