Jinhuo Wang

This study focuses on structural biomimetics, using bamboo as the biomimetic object. Owing to the porous and lightweight characteristics of bamboo, its macroscopic structure was simplified and simulated to design a pipeline. The changes in pore structure and quantity gradient (number ratio of inner-to-outer pores) parameters were imported into ABAQUS for simulation. The photopolymerization three-dimensional printing technology was used to prepare test specimens for investigating the compression performance of bamboo-like structural pipelines. Under the same pore structure, the simulation and experimental results were consistent. The pipeline structure at a quantity gradient ratio of 11:17 exhibited the most stable compression performance among different quantity gradients. Under the same quantity gradient, the optimal comprehensive compression performance and lightest material structure were achieved when the pore structure became circular. The change in the quantity gradient significantly impacted the compression performance of the pipeline. Therefore, the quantity gradient was the main factor affecting the compression performance of the pipeline.

All solid-state lithium batteries have high energy density, good safety, and broad prospects. However, the poor compatibility of the electrolyte/electrode interface limits its development. To improve the interface contact performance of batteries, this study proposes an ultrasonic-press fusion method. The electrolyte/electrode structure was pressed by an ultrasonic sonotrode, and fused tightly via thermal and mechanical effects produced by ultrasonic-press fusion. The results showed that the charge transfer impedance at the battery interface was reduced by 80.3% in AC impedance testing, and the battery interface impedance performance was significantly improved. By observing the surface and interface morphology of the electrolyte, it was found that ultrasonic-press fusion improved the electrolyte interface contact. The electrolyte melted and produced microscale rheological behavior under the action of ultrasonic-press fusion, ultimately filling the capillary structure of anode in the battery, improving contact performance of the interface. Furthermore, a molecular dynamics model of the interface was constructed to calculate the contact performance. It was found that ultrasonic-press fusion generates thermal and mechanical effects. The thermal effect facilitates the electrolyte melts, and the mechanical effect causes the melt to vibrate, which coordinate and act on the electrolyte and cause the electrolyte to solder to the anode.

Carbon fiber reinforced polymer (CFRP) blades are often exposed to wild and even harsh environments. The durability of the blade can be greatly improved by adhesively bonding a Ni erosion shield to the leading edge. In a traditional bonding process, the permeation of adhesive is poor at the interface, which gives an insufficient micromechanical interlocking. In this study, ultrasonic vibration was applied during the bonding process of sandblasted Ni plates and CFRP laminates. The values of shear strength were measured by tensile tests to verify the strengthening effect of applying ultrasonication. The cross-section of the bonded interface was characterized by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), and the surfaces with different treatments were explored by atomic force microscopy (AFM). The cross-sectional morphology and failure model of the samples were investigated. The strengthening mechanism was then studied by a molecular dynamics method. For the simulation of molecular dynamics, the CFRP/Ni bonding interface model was designed using the Materials Studio software package. The Perl scripts were used to simulate the ultrasonic vibration with different frequencies and amplitudes. The results showed that the ultrasonic process could improve the permeability and uniformity of the adhesive, enhancing the micromechanical interlocking effect.

All-solid-state polymer lithium batteries have good safety, stability, and high energy densities and are employed in wireless sensors. However, the solid contact between the polymer electrolyte and the cathode leads to high interface resistance, limiting the broad application of solid-state lithium batteries. This paper proposes an ultrasonic fusion method to reduce the interface resistance between the polymer electrolyte and the cathode. The method applied a high-frequency ultrasonic vibration technique to impact the polymer electrolyte/cathode structure, melting the electrolyte at the interface and thus generating good contact at the interface. The experimental results showed that the ultrasonic fusion method decreased the interface resistance between the polymer electrolyte and the cathode by 96.2%. During the ultrasonic fusion process, high-frequency ultrasonic vibrations generated high temperatures at the interface, and the polymer electrolyte became molten, improving the contact between the electrolyte and the cathode. The ultrasonic fusion method eliminated the gaps at the interface, and the interface became more compact. Furthermore, ultrasonic vibrations made the molten electrolyte fill the holes in the cathode, and the contact area was enhanced, providing more Li⁺ ions transmission paths.

Despite widespread attention to solid polymer electrolytes owing to their excellent safety performance and flexibility, low ionic conductivity at room temperature limits their practical applications. Here, the experimental method and molecular dynamics simulation method are performed to explore the effect of ultrasonic vibration on solid polymer electrolytes. The experimental results show that the electrolyte possesses good electronic insulation and electrochemical stability, and the ionic conductivity of the electrolyte with ultrasonic treatment is increased by 72.72% at room temperature. Molecular dynamics simulation results reveal that ultrasonic vibration promotes the dissociation of lithium salt and increases the number of effective Li⁺ ions in the electrolyte. In addition, ultrasonic vibration increases free volume of the electrolyte. It provides more space for the transmission of Li⁺ ions, thus benefits the conduction of Li⁺ ions of the solid polymer electrolyte.