In this paper, the responses of machined surface roughness and milling tool cutting forces under the different milling processing parameters (cutting speed v, feed rate f, and axial cutting depth a_p) are experimentally investigated to meet the increasing requirements for the mechanical machining of T2 pure copper. The effects of different milling processing parameters on cutting force and tool displacement acceleration are studied based on orthogonal and single-factor milling experiments. The three-dimensional morphologies of the workpieces are observed, and a white-light topography instrument measures the surface roughness. The results show that the degree of influence on S_a (surface arithmetic mean deviation) and S_q (surface root mean square deviation) from high to low level is the v, the f, and the a_p. When v = 600 m/min, a_p = 0.5 mm, f = 0.1 mm/r, S_a and S_q are 1.80 μm and 2.25 μm, respectively. The cutting forces in the three directions negatively correlate with increased cutting speed; when v = 600 m/min, F_x reaches its lowest value. In contrast, an increase in the feed rate and the axial cutting depth significantly increases F_x. The tool displacement acceleration amplitudes demonstrate a positive relationship. Variation of the tool displacement acceleration states leads to the different microstructure of the machined surfaces. Therefore, selecting the appropriate milling processing parameters has a positive effect on reducing the tool displacement acceleration, improving the machined surface quality of T2 pure copper, and extending the tool’s life. The optimal milling processing parameters in this paper are the v = 600 m/min, a_p = 0.5 mm, and f = 0.1 mm/r.

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.

Textured surfaces have been widely applied in the field of engineering for friction reduction, but research on the effects of different texture design parameters on the wear and fatigue resistance of bearing steel remains insufficiently explored. In order to improve the anti-wear and anti-fatigue performance and prolong the service life of bearing steel, surface texturing technology was applied to fabricate textured GCr15 bearing steel materials. In this work, micro-groove surface texture was designed by hydrodynamic theory, then, it was fabricated on the GCr15 bearing steel surface using nanosecond laser processing. The depths (15 μm, 30 μm), spacing (100 μm, 200 μm, 300 μm), and friction angles (30°, 60°, 90°) of micro groove were selected as the primary parameters for micro groove fabrication. The friction and wear tests and rolling contact fatigue (RCF) tests were conducted to investigate the lubrication tribological properties. The results indicated that micro-groove spacing of 300 μm significantly reduces the coefficient of friction (CoF), depth of 30 μm produces a higher hydrodynamic pressure, and friction angle of 60° has a lower CoF value. Compared to the untextured samples, the RCF life of micro-groove surface texture sample is improved, and the median RCF life is increased by 36.5%. And it could be attributed to the dispersion effect of micro-groove surface texture on stress concentration. The findings indicate that a well-designed micro-groove structure can enhance the fluid dynamic pressure lubrication effect to a certain degree. In comparison to smooth surface specimens, those with micro-grooves exhibit reduced friction.

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.

A magnetic field induced by an electromagnetic coil is the key variable that determines the performance of a magnetically driven actuator. The applicability of the empirical models of the coil turns, static resistance, and inductance were discussed. Then, the model of the mean magnetic field induced by the coil was established analytically. Based on the proposed model, the sinusoidal response and square-wave response were calculated with the wire diameter as the decision variable. The amplitude and phase lag of the sinusoidal response, the time-domain response, steady-state value, and the response time of the square-wave response were discussed under different wire diameters. From the experimental and computational results, the model was verified as the relative errors were acceptably low in computing various responses and characteristic variables. Additionally, the optimization on the wire diameter was carried out for the optimal amplitude and response time. The proposed model will be helpful for the analytical analysis of the mean magnetic field, and the optimization result of the wire diameter under limited space can be employed to improve the performance of a magnetically driven actuator.