Evaluation of Vibroacoustic Performance of a Multilayered Submersible Hull using Energy Finite Element Analysis

Abstract Energy finite element analysis (EFEA) is a numerical technique that computes the vibration and the sound radiated from complex structures at higher frequencies where conventional finite element methods cannot operate efficiently. In order to advance the use of EFEA for evaluating the vibroacoustic characteristics of a full-scale underwater vehicle, we developed a capability that accounts for multiple decoupling layers attached on the outer hull of the submerged vehicle during the structural–acoustic computations. A development for modeling the exterior non-reverberant acoustic domain was also completed. The outer hull is modeled as a wave-bearing domain that carries bending, longitudinal, and in-plane shear waves. Each decoupling layer is modeled as a wave-bearing domain containing dilatational and shear waves. All wave fields in the aforementioned domains are considered as reverberant. The external fluid is modeled using the non-reverberant acoustic formulation. The coupling between waves in adjacent wave-bearing domains is considered by creating joints at the interfaces between them. EFEA results for a representative multilayered hull system under external or internal excitation are compared to two-dimensional analytical solutions. An analysis for a generic but representative bow sonar dome is also performed and its vibroacoustic response to an external excitation is calculated using the developed EFEA modeling capability. Subsequent simulations demonstrate how modifications in the material properties of the multiple decoupling layers impact the energy distribution within the vehicle system.