RESONANT WAVE-PROPAGATION IN GUN TUBES WITH ECCENTRIC BORES

An analysis of the steady-state vibrations of gun tubes with eccentric bores is performed entirely within the framework of three-dimensional linear elasticity. The dispersion curves for the eccentric cylindrica l tube are obtained by satisfying the differential equations and bound ary conditions on the external cylindrical surface exactly and the bou ndary conditions on the eccentric inner cylindrical surface variationa lly. The resulting solutions clearly exhibit the coupling between the extensional and flexural motions. The forced vibrations are treated by satisfying the continuity conditions at the interface of the moving s tep in bore pressure using a variational principle in which all condit ions, i.e., those of both constraint- and natural-type, appear as natu ral conditions. The calculations reveal the existence of resonance at critical velocities and increasing coupling to flexural motions with i ncreasing eccentricities.