不同应力状态下膨胀管力学性能试验研究

An experimental study of the expandable tube in different stress conditions

通常膨胀管在变形后壁厚不均匀度、管体弯曲程度会增加,导致膨胀管的抗拉、抗挤毁等力学性能下降。利用网格法分析了不同应力状态下膨胀管在膨胀过程中的金属塑性流动过程,并通过室内试验进行了对比研究,详细分析膨胀过程中的宏观现象。结果表明,残余应力会增加膨胀管塑性变形力,使膨胀过程困难,膨胀后管体弯曲变形严重;处于应力状态的膨胀管膨胀后管体网格在一侧堆积,表明金属塑性流动过程沿轴向不均衡。

Generally speaking, the unevenness of wall thickness and the bending of the expandable tube will increase after it undergoes deformation, which leads to the decrease of its tensile and anti-collapse mechanical properties. The grid method was adopted to analyze the flow process of metal plasticity during the expansion process of the tube in different stress conditions. It was studied through the laboratory experiment and the macroscopic phenomenon in the expansion process was analyzed in detail. The result shows that the residual stress will increase the plastic deformation force of the tube and make the expansion process difficult. The tubular deformation bending becomes serious after expansion. The grids of the tube in the stress condition accumulate on one side, which shows that there is an axial unevenness in the flow process of metal plasticity.