基于塑性失稳的圆管对称压缩研究

Symmetry compression based on plastic instability of circular tubes

基于塑性失稳的管-管连接工艺是新研发的管类连接技术。为了获得管-管连接所需参数,针对圆管压缩形成失稳褶皱的行为进行了试验和仿真研究。进行了圆管单向拉伸试验和自由压缩试验,通过圆管自由压缩和约束压缩过程的有限元仿真,深入讨论了管坯细长比对压缩失稳形成的褶皱数目和形态的影响规律以及褶皱形成与压力的关系。结果表明：圆管压缩失稳形成的褶皱数目和褶皱形态与管的细长比（定义为l/r0）密切相关。当管坯细长比在0-0.375内,不能形成褶皱;在0.438-1.5范围内可形成单个褶皱,在1.56-2.43范围内可形成2个褶皱,大于2.5则形成3个或更多褶皱。

A new technology of joining two tubes was developed based on plastic instability. In order to obtain parameters of this join method,the unstable wrinkles produced by compressing circular tubes were investigated,and their experiments and finite element simulation were conducted. By means of uniaxial tension and free compression tests,focusing on finite element simulation of tube free compression and constraints compression processes,the influences of the slenderness ratio of tubes on the number and formation of wrinkles formed by compression instability and the relationship bewteen wrinkle and pressure were further discussed. It is shown that the slenderness ratio（ l/r0） has an obvious effect on the formation and wrinkle numbers. When l/r0 is from 0 to 0. 375,the compression wrinkles cannot be formed. When l / r0 is from 0. 438 to 1. 5,one wrinkle is formed. If l / r0 is from 1. 56 to 2. 43,two wrinkles are formed. If l / r0 is larger than 2. 5,three or more wrinkls will be formed.