This review examines the application of aramid fiber-reinforced plastics (AFRPs) in the aerospace industry, highlighting their significance in enhancing aircraft performance. Aramid fibers, such as Kevlar^® and Twaron^®, have emerged as key materials due to their exceptional tensile strength, low density, and thermal stability. However, challenges persist in manufacturing, durability, and multifunctionality. This paper evaluates the latest advancements in AFRP, focusing on how molecular structure, interfacial engineering, and manufacturing innovations influence performance. It addresses questions on improving adhesion, efficient manufacturing methods, enhancing durability under extreme conditions, and developing multifunctional AFRP. By analyzing breakthroughs from 2020 to 2025 and proposing targeted solutions, this review aims to help AFRP meet the demands of future aerospace systems.

In aeronautical applications, composite additive manufacturing (CAM) is transforming aircraft design by enabling unprecedented lightweighting and functional integration. However, industrial adoption remains limited due to insufficient understanding of the complex interplay among materials, processes, designs, and performance. Existing reviews lack an integrated analytical framework; thus, this study pioneers a closed-loop “Material-Process-Design-Performance (MPDP)” framework for critical analysis. We systematically categorize aerospace-relevant composite systems and core AM technologies, emphasizing their interactions and constraints. Crucially, we demonstrate how AM design bridges material limitations and performance breakthroughs. Validation via aerospace case studies confirms the framework’s efficacy and reveals core bottlenecks: performance consistency, quality control, and certification gaps. We argue that transitioning from isolated optimization to collaborative co-optimization of materials, processes, and design is essential for CAM’s advancement. Finally, we propose a strategic development pathway to guide future research and industrial translation, particularly for next-generation aircraft and spacecraft systems.

The solidification cracking behavior in laser welds of steel/copper dissimilar metals was systematically investigated. T2 copper and SUS304 stainless steel were used in the study. The results showed that the occurrence of solidification cracking in welds was the synergistic effect of ε phase liquation, inclusions and composition segregation. During the welding process, the liquation of grain boundaries substantially reduced the cohesion between adjacent grains, as well as the resistance for intergranular crack propagation. The composition segregation inside the grains could induce lattice distortion, thus reducing the plastic deformation capacity of the material itself and concurrently increasing the susceptibility to cracks. In addition, an effective solution for inhibiting solidification cracking was proposed by using an oscillating laser, and the inhibition mechanism was further discussed. Laser oscillating welding significantly promoted grain refinement, solute diffusion and the formation of uniformly distributed ε-Cu precipitated phases in welds. It can improve the intergranular bonding, reduce the susceptibility to solidification cracking and increase the resistance to plastic deformation. The tensile strength of joints using laser oscillating welding is 251 MPa, 35.7% more than 185 MPa using laser welding. Meanwhile, the strain of joints using laser oscillating welding is 3.69, a 96% increase compared to 1.88 using laser welding.

A novel resonator-based metasurface is devised to control reflected underwater waves. Each metasurface unit is constructed with an aluminum plate attached to a lead mass. By tailoring the thickness of the plate, full 2π phase shift of the reflected wave can be achieved. Examples of redirection, focusing, and directional carpet cloaking are demonstrated as applications. The target frequency can be as low as 500 Hz and it can operate in a broadband range. Slight modifications allow the design to perform excellently from tens to thousands of hertz. This metasurface provides a new design paradigm when there is a need to manipulate low frequency underwater waves, such as in submarines for stealth operation or detection-signal manipulation to provide deceptive information.

An extremely thin metasurface is proposed for manipulating underwater reflected waves. Each metasurface unit is only 1/61.7 of the target wavelength in thickness and comprises an air cavity capped with a thin vibration plate held in place by rubber spacers on steel supports. The unit-cell design is thin, simple, and can be adjusted to obtain a full 2π phase shift in water waves that are reflected from the metasurface. It also provides this phase shift for a broad frequency range of 20–800 Hz for incident waves. The effectiveness of the design and the resolution of the expected effect is demonstrated for sharp focusing, self-bending, and directional carpet cloaking, which are applications with great potential in energy harvesting, underwater communication, and submarine stealth and antidetection.

Based on the concept of sustainable development, to promote the development and application of renewable energy and enhance the capacity of renewable energy consumption, this paper studies the design and optimization of renewable energy hydrogen production systems. For this paper, six different scenarios for grid-connected and off-grid renewable energy hydrogen production systems were designed and analyzed economically and technically, and the optimal grid-connected and off-grid systems were selected. Subsequently, the optimal system solution was optimized by analyzing the impact of the load data and component capacity on the grid dependency of the grid-connected hydrogen production system and the excess power rate of the off-grid hydrogen production system. Based on the simulation results, the most matched load data and component capacity of different systems after optimization were determined. The grid-supplied power of the optimized grid-connected hydrogen production system decreased by 3347 kWh, and the excess power rate of the off-grid hydrogen production system decreased from 38.6% to 10.3%, resulting in a significant improvement in the technical and economic performance of the system.