高应变率下金属柱壳动态变形及形成破片特性研究

Dynamic Deformation and Fracture Fragmentation Behavior of Metal Cylindrical Shell at High Strain Rates

针对高应变率下金属柱壳动态变形及断裂响应问题,以50SiMnVB钢和40CrMnSiB钢壳体材料为研究对象,应用超高速摄影技术以及Autodyn数值模拟软件研究了壳体在高应变率下的动态变形过程。获得了壳体外壁自由面径向位移以及速度变化规律,并对回收所得破片的尺度分布规律以及断裂特性进行了分析。结果表明:壳体内部裂纹贯穿整个壁厚发生在20~25μs之间;40CrMnSiB钢壳体达到的稳定速度比50SiMnVB钢壳体提高了8.1%;试验回收所得壳体环向方向断裂形成的破片宽度变化呈正态分布,且40CrMnSiB钢壳体形成的破片质量在0.1 g以上数目比50SiMnVB钢壳体增加了49%,破碎程度更加严重。

To understand the complex dynamic response of deformation and fracture of metal cylindrical shell at high-strain rates loading,the cylinder shells fabricated from 50 SiMnVB steel and 40 CrMnSiB steel were selected as the objects for study. The ultra-high speed photographic technology and AUTODYN-2 D finite element software are applied to research the dynamic deformation of shell at high strainrates,which obtaine the variation of radial displacement and velocities of outer-wall from the shell,and the fragment mass distribution and fracture fragmentation behavior of the resulting fracture fragments are analyzed. The results reveal that the phase of cracks penetrating the entire casing wall thickness occurs within the time range of 20-25 μs,and the velocity of 40 CrMnSiB steel shell is increased by 8. 1%,compared with that of 50 SiMnVB steel shell. Moreover,the distribution of fragments width is of Gaussian-distribution,the fragmentation degree of fragments formed by 40 CrMnSiB steel shell is more serious,and the number of fragments with mass of more than 0. 1 g is increased by 49% compared with that of50 SiMnVB steel shell.