THE DEVELOPMENT OF A METHOD FOR DETERMINING THE RESPONSE OF A THIN HEMISPHERICAL SHELL TO THE INITIAL PRESSURE PULSE OF AN UNDERWATER EXPLOSION.

Abstract : A method is derived for determining the dynamic, elastic response of a thin hemispherical shell subjected to a head-on attack by the initial shock wave of an underwater explosion. The shell which is fastened to the end of a fixed, semi-infinite tube of the same radius is surrounded by a high density fluid similar to water, and the internal cavity of the shell is filled with a low density fluid similar to air. The initial shock wave moves through the high density fluid. In the neighborhood of the obstacle, the shock front propagates in the direction of the axis of the semi-infinite tube and at time equal to zero (+) makes initial contact with the obstruction at the tip of the hemisphere. The problem is approached entirely by analytical methods. Approximate expressions which are valid for small time are obtained. Numerical results are calculated for a steel shell immersed in sea water: these results are presented in the form of tables and plots. (Author)