【作者】 马明娟；

【导师】 詹梅；

【作者基本信息】 西北工业大学 ， 材料加工工程， 2007， 硕士

【摘要】 大型复杂薄壁壳体是广泛应用于航空航天、兵器等领域的一类重要的空心回转体零件。由于受到材料成形极限等因素的限制，成形此类回转体零件往往需要采用多道次旋压工艺。了解和掌握大型复杂薄壁壳体多道次旋压成形机理及规律是研究和发展该技术迫切需要解决的关键问题。为此，本文基于ABAQUS弹塑性显式和隐式有限元平台Explicit & Standard，研究建立了该成形过程的三维有限元模型，并分析了其成形机理及工艺参数对成形过程的影响规律。主要研究内容和结果如下： 建立了包含回弹和退火工序的符合实际并兼顾计算精度和效率的大型复杂薄壁壳体多道次旋压的三维弹塑性有限元模型，解决了其中涉及到的关键问题，并验证了模型可靠性。该模型的建立，为深入揭示大型薄壁壳体多道次旋压成形机理及工艺参数对其成形过程的影响规律奠定了基础。 基于上述模型，研究获得了大型复杂薄壁壳体多道次旋压成形过程中的应力应变及壁厚的分布和变化特征：随着成形过程的进行，多道次旋压成形过程中应力应变极值呈现增大趋势；并且应力应变最大值出现在旋轮与坯料接触处(即成形区)。沿工件母线方向，壁厚逐渐减小，在旋轮与毛坯接触处壁厚剧烈减薄。回弹对应变和壁厚的分布影响不大，但是对应力分布有较大影响。 进而研究揭示了旋轮安装角、摩擦系数、旋轮进给比对大型复杂薄壁壳体旋压成形过程中第一道次旋压的应力应变、壁厚和直径差的影响规律。结果表明：旋轮安装角对应变和壁厚影响不大，对工件直径差影响较大；随着摩擦系数的增大，工件壁厚的均匀性明显改善，但是直径差越来越大；当旋轮进给比较大时，壁厚分布不均匀。 最后研究揭示了摩擦系数和旋轮进给比对大型复杂薄壁壳体第二、三道次旋压的应力应变、壁厚和直径差的影响规律。结果表明：随着摩擦系数的增大，壁厚极大值变化不大，壁厚极小值先增大后减小，壁厚差极大值先减小后增大；直径差先增大后减小。随着旋轮进给比的增大，壁厚差极大值逐渐减小；直径差先增大后减小。这些结果可为相关工艺参数的确定和优化设计提供理论依据。更多还原

【Abstract】 A large complex thin-walled shell is a kind of important hollow rotary parts, widely used in aerospace, aeronautics and military industry. Because of the limitation of material forming limit and other factors, it is necessary to produce this kind of parts by multi-pass spinning technology. Research on the deformation mechanism and deformation laws of the multi-pass spinning of large complex thin-walled shell is a key problem urgently to be solved for the research and development of the spinning technology. So, in this dissertation, based on ABAQUS/Explicit & Standard, a 3D FEM model of this forming process is established firstly, and then the deformation mechanism and the influencing laws of technological parameters on the process are investigated. A brief introduction to the project and its main results are as follows:At first, a 3D Elasto-plastic FEM model including springback and annealing operation of multi-pass spinning of large complex thin-walled shell has been developed. Both computation accuracy and efficiency are taken in account, and some key technologies during the establishing process of the model have been solved. The model has been tested to be reliable. The establishment of the model lays a foundation for the research on the deformation mechanism and the influencing laws of forming parameters on the process.Then, based on the model established above, the distribution and variation features of the stress and strain, the wall thickness during the process of multi-pass spinning of the large complex thin-walled shell have been obtained. In the forming process, the maximal stress and equivalent plastic strain, which lie in the zone contacting with rollers all the time, increase during multi-pass spinning process. The wall thickness decreases gradually along generating curve of parts from its bottom to opening, and the wall thickness at the place which rollers contact with blank is the thinnest. Springback has no dramatic effect on equivalent plastic strain and wall thickness but brings about notable influence on stress.Further more, the influence laws of roller setting angle, friction coefficient between roller and blank and feed rate of roller on stress, strain, the wall thickness and diameter difference have been revealed during the first pass spinning process of large complex更多还原