微缺陷对圆管膨胀断裂的影响

通过理论和数值模拟分析了缺陷方向和位置对圆管膨胀破裂的影响，采用微缺陷研究方法进行了新的解释。采用含微缺陷的圆管模型探讨了微缺陷对圆管膨胀断裂影响，表明微缺陷将加速圆管径向扩展和剪切扩展相互贯通的过程。分析了实验获得的膨胀断裂应变与作为材料基本参数提供给计算程序的断裂（失效）应变的关系，说明在考虑圆管沿壁厚的破裂过程中，两者不是同一概念，只有将实验获得的断裂应变经过一定的推导后才能作为材料基本参数用于程序计算。

Influences of microdefects on expanding fracture of a metal cylinder

By theory and numerical simulation, influences of direction and location of defects on expanding fracture of a metal cylinder were analyzed and a new explanation was preasented by the microdefect methods. A computational model for the cylinder containing microdefects was adopted to explore influences of microdefects on expanding fracture of a metal cylinder. Computational results show that microdefects can quicken the radial extension of the cylinder and mutual impenetration of shear extensions. Analysis indicates that the experimental expanding fracture strain is different from the fracture strain as a material parameter offered to the computational program during rupture of the cylinder along its wall thickness directoion, and the two strains have a certain relation.