圆柱壳纯弯曲时塑性失稳临界曲率半径模型  

A CRITICAL RADIUS MODEL FOR PLASTIC BUCKLING OF THE CYLINDRICAL SHELL UNDER PURE BENDING

作　　者：张子骞[1] 颜云辉[1] 杨会林[1] 

机构地区：[1]东北大学机械工程与自动化学院,沈阳110004

出　　处：《固体力学学报》2014年第4期347-356,共10页Chinese Journal of Solid Mechanics

基　　金：国家高技术研究发展计划863项目(2008AA04Z135)资助

摘　　要：薄壁管材在等曲率矫直生产中,塑性失稳临界曲率半径作为重要的工艺参数,直接决定了设备结构和产品质量.而目前现场仍沿用经验图表结合人工经验和反复试矫对其进行估定,亟待建立针对性的临界曲率半径数学模型以指导生产.在力学建模和分析时,就是确定具有初始曲率的圆柱壳体在纯弯曲条件下塑性失稳的临界曲率半径,为此从旋转壳体一般几何方程出发,基于J2形变理论和能量理论,运用里茨法建立了圆柱壳体在纯弯曲条件下塑性失稳时的临界弯矩,以此确定了临界曲率半径模型,并给出了数值解法.应用ANSYS/LS-DYNA进行了有限元动态仿真试验,证明了模型是近似正确的,并通过仿真对比分析证明了轴向起皱先于截面畸变是圆柱壳体在纯弯曲条件下塑性失稳的主要模态.In manufacturing of straightening thin-walled tubes with equal curvature, the critical curva- ture radius of thin-walled tubes is a main straightening technical parameter, which directly decides the structure of equipment and the quality of products; however, its estimation usually rests with the experien- tial data and experience of skilled laborers, thus a quantitative model for the critical radius is needed. For this purpose,a cylindrical shell under pure bending is analyzed and the critical bending-moment of plastic instability is obtained. Based these, a quantitative model of the critical radius is built, and a numerical meth- od is suggested to solve it. In order to validate it,the commercial software ANSYS/LS-DYNA is employed to simulate the plastic instability of thin-walled tubes. Results show that the present quantitative model is approximately correct, and wrinkling on the compression side of the cylindrical shell occurs before buckling due to ovalisation,which is a main instability mode of the cylindrical shell under pure bending.

关 键 词：薄壁管材 圆柱壳体 纯弯曲 塑性失稳 临界曲率半径 

分 类 号：O344[理学—固体力学]