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• A PMI foam-filled multibeam antenna structure (PFMAS) is proposed for mutibeam radiation and load-bearing integrating. • The FR-4 adding can effectively enhance dispersion characteristics of the SSPPs structures, while increasing the load-bearing performances obviously. • By controlling the position of FR-4 laminates, the radiation direction of PFMAS can be controlled, like four-beam and eight-beam radiation. • Besides EM radiation properties the proposed PFMAS also has load-bearing and energy absorption advantages. The conventional antennas will increase the radar cross section of aircrafts and affect their aerodynamic performances, a novel antenna scheme for radiation and load-bearing integrated design based on composite sandwich structure is proposed. By constructing spoof surface plasmon polaritons (SSPPs) structure and combining it with glass fiber composite (FR-4) plates, the radiation direction of the monopole can be controlled and the antenna will be endowed with load-bearing capacity. At the meantime, polymethacrylimide (PMI) foam is filled in its spacing to improve the mechanical performances greatly. Through electromagnetic (EM) simulation and test, it is found that four-beam radiation in different directions and eight-beam radiation can be realized by changing the position of the FR-4 laminates, and the bandwidth is all about 1 GHz with a peak gain about 6.5 dBi. Out-of-plane compression experiment indicates that the proposed PMI foam-filled multibeam antenna structure (PFMAS) gathers the high load-bearing capacity of multibeam antenna structure (MAS) and the high energy absorption characteristics of PMI foam, showing an obvious coupling effect. Its specific compressive strength is 150.10 % and 6.28 %, and energy absorption capacity per unit volume is 169.91 % and 362.08 % higher than that of PMI foam and MAS, respectively. The proposed PFMAS improves the structural utilization efficiency, and can be applied to some interlocking units of square honeycomb structure to endow multibeam radiation characteristics, which can expand the application of integrated antenna structures effectively. [ABSTRACT FROM AUTHOR]

This paper considers the problem of optimal coordination of active steering and direct yaw moment for general electric vehicles equipped with in-wheel motors and steer-by-wire devices. As a typical over-actuated system, vehicle planar motion shows flexible control performance under different wheel actuations, thus achieving the optimal integration among them is of critical significance. Based on the modeling from wheel actuations of motor torques and wheel angles to vehicle planar motion states, this paper proposes an optimal hierarchical control framework composed of a reference state generator, a linear time-varying model predictive controller (LTV-MPC), and an optimal control allocator. Motor torques and wheel angles are decoupled as equivalent distributed variables by linearization technique. Then an optimal allocation framework is formed towards the trade-off between driving security and power saving, and a compensation module based on the back-propagation neural network (BPNN) is designed to guarantee the control allocation accuracy. Holistic multi-objective optimization is demonstrated through Co-simulations with Matlab/Simulink and TruckSim. Results verify the effectiveness of the proposed control strategy. • LTV-MPC based hierarchical control framework is proposed for an n -axle distributed-driven electric vehicle. • Active steering and direct yaw moment are integrated through the optimal coordination of distributed wheel actuations. • Multi-objective optimization towards the tradeoff between tire force utilization and motor power consumption is realized. [ABSTRACT FROM AUTHOR]

Carbon fiber (CF) which has both mechanical and electromagnetic (EM) characteristics can achieve multiple functions by special designing, such as load bearing and EM wave absorption. In this work, based on the excellent mechanical properties of hierarchical corrugated sandwich structure (HCSS), a novel CF interlaminar reinforced hierarchical corrugated metamaterial absorber (HCMMA) is constructed. By stitching CF arrays onto the core member face of HCSS, the spoof surface plasmon polaritons (SSPPs) structure is constructed, endowing HCSS with EM wave absorption ability and enhancing its interlaminar mechanical properties. Simulation and experimental results show that the proposed structure achieves efficient absorption (average over 90 %) of 4 - 12 GHz EM wave with an incident angle of 0 - 60°, which realized by the dielectric loss of EM wave and local strong E-filed formed by SSPPs structure. In addition, the stitching of CF arrays effectively limit the local buckling-debonding deformation region of the core member face, which greatly improves its mechanical performances. Thereby the compressive strength and specific compressive strength of the proposed structure is increased by 32.7 % and 16.7 %, respectively. Based on the multifunctional design characteristics of CF, the proposed structure effectively expands the application of composite sandwich structures in the field of multifunctional design. [ABSTRACT FROM AUTHOR]

Aiming to enhance electromagnetic (EM) wave absorption and compressive properties of sandwich structure, a novel scheme of structure/function integrated design was proposed based on composite square honeycomb structure (SHS). By using the EM characteristic of carbon fiber (CF), a novel spoof surface plasmon polaritons (SSPPs) structure that serves as the core of EM wave absorption can be obtained through winding continuous CF wires around orthogonal honeycomb walls. Numerical simulation and experimental verification show that the interlocked SHS realizes broadband (5–20 GHz), multiangle (0-70°) and efficient (average over 90%) absorption performance for EM wave incident from all directions. In addition, to further improve its mechanical properties, polymethacrylimide (PMI) foam was cut and inserted into the space of honeycomb core, forming PMI foam-filled SHS. Out-of-plane compression result indicates that due to coupling effects between honeycomb walls and PMI foam, its specific stiffness and specific compressive strength can be dramatically increased by 42% and 121%, respectively. Therefore, based on its excellent EM wave absorption and mechanical performances, the proposed interlocked SHS is highly competitive in EM wave absorption and load-bearing applications. [ABSTRACT FROM AUTHOR]

Despite the promise for stem cell-based tissue engineering for regenerative therapy, slow and insufficient vascularization of large tissue constructs negatively impacts the survival and function of these transplanted cells. A combination of channeled porous silk scaffolds and prevascularization with endothelial cells was investigated to test the ability of this tissue engineering strategy to support rapid and extensive vascularization process. We report that hollow channels promote in vitro prevascularization by facilitating endothelial cell growth, VEGF secretion, and capillary-like tube formation. When implanted in vivo , the pre-established vascular networks in the hollow channel scaffolds anastomose with host vessels and exhibit accelerated vascular infiltration throughout the whole tissue construct, which provides timely and sufficient nutrients to ensure the survival of the transplanted stem cells. This tissue engineering strategy can promote the effective application of stem cell-based regeneration to improve future clinical applications. [ABSTRACT FROM AUTHOR]