Experimental and analytical investigations on vibro-acoustic characteristics of a submerged submarine hull coupled with multiple inner substructures

Inner substructures, which can be generally compartmentalized into axisymmetric and non-axisymmetric ones, are believed to significantly affect the vibro-acoustic characteristics of submarine hulls. In this paper, the vibro-acoustic behaviors of a submerged submarine hull coupled with multiple inner substructures are experimentally and analytically studied. The vibration of the stiffened hull is uniformly expressed by Flügge shell theory and power series method. The sound pressure is described by surface Helmhotlz integral. Diverse types of non-axisymmetric internal substructures are modeled by FEM. The analytical model of the hull and FE models of inner substructures are perfectly coupled in 6 DOFs through the matrix reduction technique. By assembling the generalized stiffness matrices of two types of subsystems, the final governing equation of the coupled model is established. To validate the reliability of the present method and examine the effects of non-axisymmetric inner substructures on vibro-acoustic behaviors of the hull, a large-scaled submarine hull with several axisymmetric and non-axisymmetric interior substructures is manufactured, and the underwater responses of the hull with and without non-axisymmetric substructures are tested and compared. Meanwhile, effects of non-axisymmetric inner substructures on vibro-acoustic characteristics of the hull are analytically discussed in wave domain and some significant phenomena are discovered.