3D-Kagome lattice sandwich panels are mainly composed of upper and lower panels and a series of symmetrically and periodically arranged lattices, known for their excellent high specific stiffness, high specific strength, and energy absorption capacity. The inherent geometrical symmetry of the 3D-Kagome lattice plays a crucial role in achieving superior mechanical stability and load distribution efficiency. This structural symmetry enhances the uniformity of stress distribution, making it highly suitable for automotive vibration suppression, such as battery protection for electric vehicles. In this study, a polyurethane foam-filled, symmetry-enhanced 3D-Kagome sandwich panel is designed following an optimization of the lattice structure. A novel fabrication method combining precision wire-cutting, interlocking core assembly, and in situ foam filling is employed to ensure a high degree of integration and manufacturability of the composite structure. Its mechanical properties and energy absorption characteristics are systematically evaluated through a series of experimental tests, including quasi-static compression, three-point bending, and low-speed impact. The study analyzes the effects of core height on the structural stiffness, strength, and energy absorption capacity under varying loads, elucidating the failure mechanisms inherent to the symmetrical lattice sandwich configurations. The results show that the foam-filled sandwich panels exhibit significant improvements in mechanical performance compared to the unfilled ones. Specifically, the panels with core heights of 15 mm, 20 mm, and 25 mm demonstrate increases in bending stiffness of 47.3%, 53.5%, and 51.3%, respectively, along with corresponding increases in bending strength of 45.5%, 53.1%, and 50.9%. The experimental findings provide a fundamental understanding of foam-filled lattice sandwich structures, offering insights into their structural optimization for lightweight energy-absorbing applications. This study establishes a foundation for the development of advanced crash-resistant materials for automotive, aerospace, and protective engineering applications. This work highlights the structural advantages and crashworthiness potential of foam-filled Kagome sandwich panels, providing a promising foundation for their application in electric vehicle battery enclosures, aerospace impact shields, and advanced protective systems.

Vibration is a prevalent phenomenon in mechanical systems, often adversely affecting equipment performance and operational stability. To address this issue, this study proposes a novel three-directional vibration absorber, which provides stiffness in three orthogonal directions. The mechanical properties of the isolator are theoretically analyzed, focusing on its load-bearing capacity and working stroke, which are influenced by the initial configuration angle of the spring assembly. The dynamic characteristics of the proposed isolator are evaluated by comparing its peak dynamic displacement and force transmissibility rate with those of a conventional linear vibration isolator. The results indicate that under low excitation amplitudes, the three-directional isolator achieves a lower peak force transmissibility but exhibits a higher dynamic displacement peak compared to the linear isolator. Furthermore, a dynamic model incorporating Coulomb friction damping is developed to assess its impact on the system’s dynamic response. The findings reveal that increasing the equivalent Coulomb friction factor effectively reduces the dynamic response amplitude and force transmission rate below the resonance frequency but exacerbates these parameters beyond the resonance point. Finally, experimental studies were conducted on the isolator prototype. The results show that the static theoretical model can well reflect the static characteristics of the isolator and the dynamic theoretical model can effectively fit the dynamic test curves of the isolator. This research provides a theoretical foundation for the further optimization and practical application of three-directional vibration isolators.