【作者】 徐照；

【导师】 林俊峰；

【作者基本信息】 哈尔滨工业大学 ， 材料加工工程， 2010， 硕士

【摘要】 板料成形在汽车、飞机、仪表等制造业中,有着广泛的应用。随着航空航天工业的高速发展,对零部件提出了轻量化、高精度、低消耗的要求。铝镁合金等轻质合金板料得到了广泛应用。但是,这些材料塑性低、成形性能差成为其加工成形的瓶颈。与传统成形工艺相比,板料液压成形技术由于其工艺柔性高,既能保证质量,又可降低成本和缩短试制周期,且一次变形量大等优点成为铝镁合金等难成形轻质板材零件提高成形极限的有效途径之一。双向加压拉深成形技术是在传统充液拉深的基础上,在成形坯料的上表面也施加液压来配合充液拉深,由于正向压力的存在,改善了变形区的受力情况,降低了传力区的负荷,从而增大了允许的变形程度,更有效地抑制减薄,提高成形极限,为复杂板材零件成形加工提供了新的途径。本文以铝合金锥底筒形件为研究对象,采用模拟与实验相结合的方法研究了工艺参数对零件成形性的影响规律。采用LS-DYNA3D对5A06铝合金双向加压拉深成形过程进行了数值模拟研究。提出了正向压力的施加方法,研究了正向压力与液室压力的匹配对零件壁厚分布的影响规律,得到了正向压力与液室压力的合理匹配关系。对成形结果进行了应力分析,分析了成形过程中塑性变形的发生发展规律,给出了典型点的应力路径在屈服轨迹上的变化。对5A06铝合金筒形件双向加压拉深成形过程进行了实验研究。设计了双向加压拉深成形工艺的模具结构,给出了提高成形极限的最佳工艺参数,总结了工艺参数对壁厚分布的影响规律,分析了成形的失效形式和失效机理,并成形出合格零件,通过对成形过程的应变测量,给出了零件在成形过程中最大厚向应变的变化规律。更多还原

【Abstract】 Sheet metal forming is widely used in the manufacturing of automobile, airplane and meters. With the high speed development of aerospace industry, the component requirements of lightweight, high-intensity, high-precision, high efficiency, low consumption were proposed, aluminum-magnesium alloy and other light-weight materials are widely applied. However, the application of light-weight materials is confined for its low plasticity and poor formability. Comparing with the conventional deep drawing, the sheet metal hydroforming is one of the effective forming methods to increase the forming limitation of the aluminum-magnesium and other low plasticity, poor formability sheets, meanwhile this technology has the super flexibility and guaranty of quality, reducing the cost and trial period..On the basis of the traditional hydromechanical deep drawing, drawing with double side pressure (DDSP) technology is also loading hydraulic pressure on the upper surface of the blank. As the exist on positive pressure, the situation of the force deformation zone was improved, reducing the loading of transfer zone, increasing the allowable deformation, inhibiting the thinning effectively, improving the forming limit. PNPH technology provides a new way for the complex parts processing of sheet metal forming.In this paper, the component of aluminum alloy with tapered bottom is as a subject, the combination of method on simulation and experiment is adopted to investigate the relation between process parameters and part formability.The numerical simulation software ETA/Dynaform5.6 is employed which is based on LS-DYNA3D to investigate the forming process of DDSP aluminum alloy (5A06) part. The loading means of positive pressure was processed. The effects of different match relation of negative pressure and positive pressure on the thickness distribution were studied and the reasonable match relation of negative and positive pressure was obtained. And the stress analysis of the forming results was made and the developing regularity of plastic deformation of PNPH was analyzed. The change of stress trace of representative points in yield ellipse has been given out.The experimental research on the DDSP of aluminum alloy (5A06) part was made. The die structure of DDSP was designed and the best process parameters to improve the forming limit were given. The effect of process parameters on thickness distribution was summarized. The failure modes and failure mechanism were analyzed. And the qualified part was obtained. The variation rule of the maximum thickness strain in the forming process was given by measuring the strain on the forming process.更多还原