内部爆炸加载条件下圆柱钢壳的动态断裂

DYNAMIC FRACTURE OF CYLINDRICAL STEEL SHELL UNDER INSIDE-EXPLOSION LOADING

在内部爆炸冲击波载荷作用下,爆炸容器的动态断裂是进行爆炸容器安全评估和失效分析的基础。为了研究爆炸容器的动态断裂特征,进行圆柱钢壳在中心装药的爆炸加载实验,采用非线性动力有限元分析程序LS-DYNA分析圆柱钢壳的弹塑性动力响应,研究圆柱钢壳的宏观变形和断口的宏观、细观形貌,分析圆柱钢壳的断裂模式及断裂机理。结果表明,圆柱钢壳纵向断口具有微孔聚集型剪切韧窝断裂特征,呈现出微孔聚集型剪切韧性断裂模式。内部爆炸冲击波加载下圆柱钢壳因径向膨胀发生动态塑性变形,产生剪切带,由于剪切带的软化效应而成为优先断裂通道,剪切带和环向拉应力的共同作用是形成微孔聚集型剪切韧窝断裂这种混合韧性断裂模式的原因。

Dynamic fracture of explosion containment vessels（ECVs） subjected to internal blast loads is the foundation for conducting safety assessment and failure analysis of ECVs. The experiments were carried out to investigate dynamic fracture characteristics of cylindrical steel shells subjected to internal blast loadings at the centers. The elastic-plastic response of cylindrical steel shells was conducted using nonlinear dynamic finite element analysis（FEA） code LS-DYNA. The fracture mode and fracture mechanism of a cylindrical shell were specially studied through analysis of deformation, macrographs and mecrographs of fracture surface and elastic-plastic respouse. The results show that the axial direction fracture surface of the cylindrical steel shell exhibits a mixed ductile fracture mode with shearing dimple by micro-void coalescence. D3~narnieal ductility deformations appear and the shear bands form when the cylindrical steel shell expands under internal blast loading. The cylindrical steel shell fractures preferentially along the shear bands due to its softening effect. The fracture mechanism is that the shear bands tear under tensile circumferential stress. The shear bands and the tensile circumferential stress dominate the final fracture mode. The fracture mode is of the ductile fracture.