【作者】 赵刚要；

【导师】 刘郁丽；

【作者基本信息】 西北工业大学 ， 材料加工工程， 2007， 硕士

【摘要】 铝合金薄壁矩形波导管是雷达和无线电通讯系统中的关键部件，绕弯成形是矩形波导管的主要加工方法。但在薄壁矩形管绕弯成形过程中极易产生失稳起皱、截面畸变、拉裂等缺陷；特别是失稳起皱，严重地影响着矩形波导管的弯曲成形质量。因此，本文采用三维有限元数值模拟技术，对薄壁矩形管绕弯成形过程失稳起皱及工艺参数对失稳起皱的影响规律进行了系统的研究。该研究对薄壁矩形管弯曲成形技术的发展及该成形过程工艺参数的选取与优化具有重要的理论意义和参考价值。本文主要研究内容和结果如下： 实验获得了3A21铝合金薄壁矩形管材料的基本力学性能，建立了材料的本构模型。在解决薄壁矩形管绕弯成形有限元建模过程所涉及的关键技术问题的基础上，采用动态显式有限元平台ABAQUS／Explicit，建立了既符合实际又兼顾计算精度和计算效率的该成形过程的三维有限元模型，并对所建模型的可靠性进行了验证。该模型的建立，为系统研究失稳起皱的产生机理及工艺参数对其的影响规律奠定了基础。 基于验证的有限元模型，系统研究了绕弯成形过程中切向应力及切向应变场的分知规律，并分析了该成形过程中压缩变形区随弯曲进程的变化规律，发现随着弯曲过程的进行压缩变形区的大小及其相对弯曲切点的位置基本保持不变，失稳起皱主要发生在弯曲初始阶段的40°内。为系统地研究工艺参数对薄壁矩形管绕弯成形失稳起皱的影响规律提供了依据。 采用所建立的有限元模型，模拟分析了工艺参数对薄壁矩形管绕弯成形失稳起皱的影响规律。结果表明：减小弯曲模与管坯的间隙、增大弯曲半径、增大弯曲模与管坯的摩擦和增加芯棒伸出量，都有利于减小失稳起皱。但当芯棒伸出量超过一定值时，芯棒支撑的管坯外侧部位就会出现凸起现象。随着芯棒与管坯间隙、防皱块与管坯间隙的增加以及芯棒与管坯摩擦系数的增大，失稳起皱波纹度先减小后增大；压块的助推速度、压块与管坯的间隙和压块与管坯的摩擦对失稳起皱的影响不显著。更多还原

【Abstract】 Aluminum alloy thin-walled rectangular waveguide tube is a key component widely used in the field of radar and radio communication system, and the rotary draw bending is the main forming method of rectangular waveguide. But wrinkling, distortion, tension crack etc are easily produced during the rotary draw bending process, especially the wrinkling seriously influence the quality of rectangular waveguide. Therefore, the wrinkling mechanism and the influencing laws of processing parameters on wrinkling in the bending process have been investigated systematically by using the 3D-FE numerical simulation technology. The achievements of this research are important to the development of rectangular tube bending technology and the determination and optimization of processing parameters. A brief introduction to the project and its main results are as follows:The primary mechanical property data of 3A21 aluminum alloy thin-walled rectangular tube has been obtained through the experiment, and then the constitutive equation has been established. Based on solving some key technological problems of the modeling in the rotary draw bending process of thin-walled rectangular tube, a 3D Elasto-plastic dynamic explicit FE model of the process has been established under the environment of the dynamic explicit FEM code ABAQUS/Explicit. And both computation accuracy and efficiency are taken into account during the establishing process of the model. And the reliability of the model has been verified by literature. The establishment of the model lay a foundation for the research on the wrinkling mechanism and the influencing laws of processing parameters on the process.Then, based on the model established above, the distribution laws of tangential stress and tangential strain have been investigated during the different stages of the bending process, and the variation rule of compression deformation area of the inner side of the tube has been also analyzed. The results indicate that the size and the relative position of the compression deformation area nearly keep unchanged with the progress of the bending process, and the bending angle at which the wrinkling is produced during the initial stage of bending process is less than 40°. The results of更多还原