爆轰加载下金属柱壳膨胀破裂过程研究

Expanding fracture of steel cylinder shell by detonation driving

采用前照明的高速分幅照相对不同壁厚的45钢柱壳在爆轰加载下的膨胀破裂过程进行了研究,实验成功拍摄到45钢柱壳前表面裂纹生成、扩展及产物泄漏的过程图像。研究表明:膨胀应变率在104s-1附近时,随着应变率的增加,45钢柱壳的各特征应变均有所增加,断裂模式由拉剪混合向单一剪切转变;45钢柱壳的膨胀破裂有一个过程,从柱壳的外壁面可以观察到裂纹生成至产物开始泄漏经历时间历程的长短与柱壳壁厚相关,柱壳壁越厚,从外壁出现裂纹到产物开始泄漏的时间间隔越长;由回收破片厚度测量推算出的膨胀断裂应变与动态实验过程中产物开始泄漏时的断裂应变基本一致。

The high-speed photography has been applied to observe the expanding fracture of the steel cylinder shells, which is driven by detonation. The clear photos of expanding process of steel cylinder shells have been obtained. The fracture strain of the expanding steel shell becomes larger when the strain rate increase to around 104 s-1; and the fracture model becomes to simple shear from tensile-shear. The time between cracks initiating on the out surface of the steel shell and the detonation product getting out gets longer when the thickness is increased. The deduced strain from the average thickness of the recovered fragments agrees with that obtained from dynamic photos.