管材流体高压成形起皱行为与皱纹控制研究进展

The wrinkling behavior of tube and its control method are the research foci in the field of hydroforming, which is of great significance to the manufacturing of integral complex thin-walled parts with high performance and lightweight used in automobile, aerospace and other important fields. The plastic buckling and wrinkling behavior of tubes under axial or combined axial and internal pressure are reviewed firstly in view of the wrinkling instability of thin-walled tubes due to the complicated loading conditions during the hydroforming process. Then, the commonly used axial critical wrinkling stress models and their application in tube hydroforming are discussed. It is found that the forming limit of the tube can be significantly improved by preforming useful wrinkles, which can accumulate materials in the deformation area in advance. In addition, the control methods of wrinkling behavior in the process of tube hydroforming are introduced emphatically. The stress distribution and the evolution of the wrinkle geometry during the wrinkling process are analyzed. Finally, it is proposed that the wrinkling behavior of tubes under three-dimensional stress state and nonuniform temperature field can be regarded as the key research direction. This is not only helpful to construct the theoretical system of wrinkling instability of tube under complex loading conditions and inhomogeneous tube, but also can improve the manufacturing capability of hard-to-deform materials tubular components with large expansion ratio.