Vehicle sound package system plays a critical role in determining vehicle’s noise, vibration, and harshness (NVH) performance. With the advent of new energy vehicles, novel acoustic challenges arise in the absence of the masking effect provided by engine noise. The need for more efficient sound package is an important topic for both automotive Original Equipment Manufacturers (OEMs) and academic researchers. Despite the wealth of research on the sound package, a comprehensive review of the state-of-the-art has been lacking. This review aims to fill this gap by providing a concise and up-to-date overview of the various noise sources and transmission paths, functions, materials, components, and study approaches involved in the vehicle sound package technology. Vehicle sound package is fundamental in controlling the engine noise, road noise, and wind noise inside the vehicle, with functions that include sound absorption, sound insulation, damping, and sealing. To optimize these functions, an assortment of materials have been employed, from conventional options like foam and fiber to more innovative solutions like plastic and rubber, as well as functional materials and multilayer composites. To enhance vehicle sound package performance, both experimental and numerical methods, such as finite element analysis (FEA) and statistical energy analysis (SEA), artificial intelligence (AI)-driven optimization are employed in academic research, while the industrial development process often involves a more intricate and practical approach. This review also makes some recommendations for future research work in this area. It is expected that this review will provide useful information for further development of vehicle sound package technology.

Underwater sound absorption materials with a stable performance at various hydrostatic pressures are important for marine applications. However, most studies about underwater sound absorption materials only focused on the performance at atmospheric hydrostatic pressure, while ignoring the influence of various hydrostatic pressures. Aiming to improve the underwater sound absorption stability of a metamaterial at various hydrostatic pressures, different structures and a Nelder–Mead algorithm with an acoustic-structure fully coupled finite element method (FEM) model are developed to optimize the structure of the metamaterial at various hydrostatic pressures. In this numerical modeling, the metamaterial is a PDMS matrix embedded with periodic cylinders. Firstly, the effect of hydrostatic pressure on the metamaterial is evaluated in the frequency range [0, 8 kHz]. Secondly, different cases are designed to improve the underwater sound absorption stability at various hydrostatic pressures, including different cylinder radii, different distances between the air cylinder and the steel backing, and different void shapes. Then two layers of air and/or steel cylinders are introduced to further improve sound absorption performance under various hydrostatic pressures. The results indicate that PDMS with two layers of air cylinders have the optimal sound absorption stability performance under various hydrostatic pressures, which can be attributed to the top layer of air cylinders absorbing the main deformation. Lastly, the optimization algorithm significantly improves the sound absorption performance of the metamaterials at various hydrostatic pressures. This combination of an optimistic algorithm and FEM can guide the design of underwater sound absorption metamaterials at various hydrostatic pressures.

Underwater sound absorption materials with broadband and resistance to high pressure are crucial for noise control in the ocean. Herein a new method is presented to synergistically improve material's resistance to high pressure with broadband by hybridizing carbon nanotubes (CNTs) with graphene nanoplatelets (GNPs) in polydimethylsiloxane (PDMS) matrix. The micro‐structure shows the geometrical synergy between the nanoplatelets (GNPs) and nanotubes (MWCNT‐COOH). Besides, GNPs also form junctions with air micro‐voids. The underwater acoustic tests reveal that, compared with equivalent nanocomposites containing only CNTs or GNPs, the hybridized materials show significantly better sound absorption performance with a high hydrostatic pressure increased from 0.4 MPa to 1.0 MPa at the frequency range of 1500 Hz to 7000 Hz. Therefore, the hybridization of one‐dimensional (1D) and two‐dimensional (2D) nano‐carbon materials provides a new route for increasing the underwater sound absorption performance at high hydrostatic pressure.