Search

AbstractDrawing inspiration from hierarchical structures, axisymmetric design layouts were introduced, and hybrid hierarchical chiral structures (HHCS) based on four- and six-chiral structures were proposed. The performance of HHCSs under in-plane compression is investigated using finite element methods and experiments. The effect of different loading conditions on the behavior of HHCSs is discussed. Under low-speed impact, HHCSs exhibit a negative Poisson’s ratio (NPR) effect, which diminishes as the velocity increases and the inertial effects gradually become dominant. The parameter study shows that increasing the connectivity between subunits and the thickness can enhance the energy absorption capacity of the structure while maintaining a good NPR effect. The conventional inclined deformation mode of the chiral structure is improved by the axisymmetric layout, which effectively improves the energy absorption. [ABSTRACT FROM AUTHOR]

This study extensively characterizes the out‐of‐plane stiffness and energy harvesting capabilities of a newly proposed anti‐trichiral hierarchical auxetic honeycomb structure, both mechanically and deformationally. By introducing a design concept based on the anti‐trichiral honeycomb (ATCH), a structure with superior out‐of‐plane load‐carrying capacity and excellent auxeticity is achieved. To validate the finite element model, compression simulations are conducted. Comparative investigations into the morphing characteristics and energy harvesting performance between the novel structure and the ATCH are performed. Additionally, the influence of various parameters on the comprehensive performance of the novel auxetic structure is explored. It has been found that the angle φ is most sensitive to the auxetic properties, while the ratio k significantly impacts energy absorption. This research advances the design of novel auxetic structures for potential applications in protective engineering. [ABSTRACT FROM AUTHOR]

In order to improve the crashworthiness of traditional Thin-Walled Struct, a new method for designing multicellular tubes is presented in this paper. In this work, multicellular columns based on origami centripetal folding method (MCOCFM) are proposed. The cross section of MCOCFM is designed in the way of origami. The mechanical properties of MCOCFM under uniaxial compression are analyzed by numerical simulation. Studies have shown that increased levels and wall thickness facilitate energy absorption. In addition, the theoretical prediction of MCF is in good agreement with the simulation results. Compared with some existing structures, MCOCFM has better crashworthiness. [ABSTRACT FROM AUTHOR]

AbstractDrawing inspiration from the branching structure of trees, a novel Tree-like Hierarchical Multi-cellular Bi-tube (THMBT) has been devised. This design merges the hierarchical distribution traits of tree branches with the superior crashworthiness of double square tube structures. Utilizing a validated finite element model, this study investigates the crashworthiness of THMBT, examining the impacts of wall thickness, bifurcation angle, and bifurcation length on its performance. The Simplified Super Folding Element theory is employed for theoretical analysis, facilitating the calculation of the mean crushing force of THMBT. Findings reveal that wall thickness exerts the most pronounced influence on crashworthiness. As wall thickness increases, THMBT-3 demonstrates a substantial 88.07% enhancement in specific energy absorption, accompanied by a notable increase in peak crushing force. Particularly noteworthy is the exceptional crashworthiness of THMBT-3 with a bifurcation angle (θ) of 60°. For instance, the crushing force efficiency of THMBT-3 with a wall thickness of 0.5 mm reaches 92.08%. Furthermore, when considering different bifurcation lengths under the same wall thickness and bifurcation coefficients (c) set to 1/3, both THMBT-2 and THMBT-3 exhibit superior impact resistance within their respective structures. This study marks a significant advancement by integrating biomimetic design with double square tubes, resulting in a substantial improvement in structural crashworthiness. The findings offer valuable insights for the further development of biomimetic and double square tubes. [ABSTRACT FROM AUTHOR]

In this study, the carbon steel substrates were coated with nickel (Ni), zinc oxide (ZnO) and ZnO/Ni coatings by electrodeposition approach and modified with stearic acid (STA)-ethanol solution to obtain STA-Ni, STA-ZnO and STA-ZnO/Ni coatings, respectively. The surface morphologies, chemical compositions and surface roughnesses of the modified coatings were characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and confocal laser scanning microscope (CLSM), respectively. The wettability tests shows that the water contact angle (WCA) of the modified coatings with micro/nanostructure are all greater than 150° and the sliding angle (SA) are all less than 10°, especially the STA-ZnO/Ni coating with a WCA of 164.3° and a SA of 2.3°, displaying the prominent superhydrophobicity. Interestingly, the three modified coatings all exhibited excellent mechanical stabilities and self-cleaning properties after being scratched by a knife blade, peeled off by adhesive tape, abrased by sandpaper, and contaminated by chalk dust. Moreover, the corrosion resistance tests confirms that the STA-ZnO/Ni superhydrophobic coating possess higher durability and anticorrosion performance than that of STA-ZnO and STA-Ni coatings. The superhydrophobic STA-ZnO/Ni composite coating prepared by two-step electrodeposition combined with low surface energy material modification designed in this work shows great potential and prospect in industrial application. [ABSTRACT FROM AUTHOR]

A quasicrystalline approximate monoclinic phase η-Al5(Mn,Cr) with a plate-like or rod-like morphology in AA5083 aluminium alloy was investigated using transmission electron microscopy. Several types of orientation relationships (ORs) between the η-Al5(Mn,Cr) phase and the α-Al matrix were observed and these ORs could be correlated with a rotation operation around the axis [ 001 ] η with an angle that is an integer times 18.5°. These multiple ORs were interpreted by utilizing an invariant deformation element model – a simplified version of three-dimensional invariant line strain analysis. [ABSTRACT FROM AUTHOR]