Calculation method with experimental validation of underwater acoustic radiation of composite laminate structures

Enhancing the acoustic radiation performance of typical composite structural parts of underwater vehicles is crucial for reducing the risk of acoustic detection and improving low-noise capabilities. This paper conducts an in-depth exploration of the acoustic radiation characteristics of composite laminate structures and introduces a numerical simulation method based on the three-dimensional (3D) sonoelasticity theory. The study analyzes and evaluates the underwater acoustic radiation of composite laminates by combining calculation method and experimentation. First, we use finite element method (FEM) to perform dynamic modeling and modal analysis of the typical laminates. The composite plate is modeled by defining the ply angle of each layer with shell elements, in order to obtain their natural frequencies and vibration modes with satisfactory calculation accuracy and efficiency. Subsequently, we use the 3D sonoelastic analysis software THAFTS-Acoustic to perform a detailed analysis of the acoustic radiation characteristics. To form a closed surface of the wet elements, a cuboid box is proposed to model the wet surface in present method. The results for the composite cylindrical shell demonstrate the good agreement of present method with the reference solution. Lastly, this paper compares the experimental results of underwater acoustic radiation of composite laminates with numerical simulation data. The calculated and experimental sound pressure level (SPL) curves are consistent in the 20–420 Hz, with differences of maximum and total SPL at each measuring point within 3 dB. This further validates the proposed numerical method. In summary, the paper proposes a numerical method for the acoustic radiation of typical composite structures, providing a scientific basis for the low-noise design of new composite materials in marine engineering equipment.