Deformation of metal pipe due to underwater shock wave

The deformation process of the metal pipes,:accelerated by underwater shock wave resulting from the underwater detonation of explosive inside the meta l pipe, was investigated by means of both the optical observation experimen t and the numerical calculation. The expanding deformation of metal pipes w as experimentally viewed by both framing and streak photographic means. A c omputer code based on the arbitrary Lagrangian and Eulerian (ALE) method wa s used to perform the numerical simulation on this problem. It has confirme d that the deformations of the metal pipes obtained from the streak photogr aphs agree quite well with those obtained by the numerical calculation. The experimental and numerical results both show that the expanding velocity a long the radial direction in aluminum pipe is larger than that in copper pi pe, under the same loading conditions; and also, the time needed to reach t he maximum radial velocity is shorter in aluminum pipe than in copper piper The calculations clearly indicate that the metal pipes are able to acquire a maximum expanding velocity along the radial direction in a very short ti me after the beginning of the action of underwater shock wave, and also thi s maximum velocity value only decreases a little in the later time period.