薄壁圆管轴向冲击下的动态特性研究

Study on Dynamic Properties of Thin-walled Circular Tubes under Axial Compression

采用落锤冲击实验机和材料实验机(MTS)研究薄壁圆管轴向载荷下的动态力学特性,得到不同冲击速度下的轴向力-位移曲线.发现惯性对薄壁圆管轴向压缩的动态吸能特性影响不大,而落锤不同冲击加载速度即代表应变率的变化引起的薄壁圆管材料屈服应力的提高,使得薄壁圆管比吸能SEA(单位质量结构所吸收的能量)和平均轴向压缩力Pm随着应变率的增加而呈上升趋势.对不同应变率下的Pm进行无量纲化处理,发现实验结果与前人推导的理论结果趋势一致.对比动态和准静态实验结果,发现圆管的动态变形模态相比准静态结果发生了改变,更高速度冲击下薄壁圆管的动态特性有待进一步研究.

The dynamic properties of thin-walled circular tubes under axial compression are studied using Drop Hammer and MTS （Material Test System）. Axial load-displacement curves under different crushing speeds are obtained from the tests. On observation of the behavior of thin-walled circular tubes under axial compression, it implies that the inertia effect has negligible influence on dynamic properties while the increment of strain-rate enhances the specific energy absorption （SEA） and mean force （Pm） of the tubes. Based on dimensionless analysis of Pm under different strain-rates, it shows that the experimental results are in good agreement with the theoretical ones obtained by former researchers. It is found from experimenting that the deformation mode of the tubes under impact is different from that under quasi-static, and further study is needed on the dynamic behavior of thin-walled circular tubes at higher speeds.