On fracture of a thin spherical shell under blast loading

The nature of fracture under impulsive loading is examined. It is shown as a consequence to Drucker's stability hypothesis that, under impulsive loading, it is strain rate and not total strain that plays the dominant role in determining fracture criteria. Rinehart and Pearson's criteria for rupture of cylindrical shells, which are consistent with the above, are extended to spherical shells. Experimental program on polystyreneplastic shells of different sizes is reported. Dominant fracture pattern observed was brittle. Also, critical velocity of straining (V _cr) was found to be directly proportional to the cube of the diameter of the shell. On the basis of dimensional considerations, it is shown that the shell-wall thickness has no effect upon the number of fragments. The effect of material properties on fracture is also examined.