Honeycomb structures are widely used in automotive and aerospace applications because of their outstanding characteristics of high strength and light weight. In this paper, a new honeycomb structure named as bionic honeycomb thin-walled structure (BHTS) which filled the column in different way inspired by the internal structure of the ladybeetle is proposed. The energy absorption characteristics of two kinds of BHTSs have been investigated comparing an original honeycomb structure with the same type of material under axial impact loading using nonlinear finite element software LS-DYNA. Dynamic loading has been carried out under the weight of 500 kg and the speed of 10 m/s. The results show that the energy absorption characteristic of BHTS which filled columns on its walls is better than that filled columns in its walls. Then the parameter studies in energy absorption of BHTS-2 have been carried out. It is found that energy absorption performance of BHTS-2 is best when the filled column number is 6 and diameter is 8 mm.

Energy absorption characteristics of bio-inspired honeycomb structure under axial impact loading

Multi-cell tubes have been widely used in vehicle engineering for their excellent energy absorption capacity. In this paper, a group of bionic multi-cell tubes (BMCTs) with quadrilateral, hexagonal and octagonal sections were proposed. The BMCTs were constructed by filling the cylindrical tubes into different position of multi-cell tubes (MCTs), which was inspired by the microstructure of beetle forewings. The finite element (FE) models under axial impact loading were established and then validated by the Simplified Super Folding Element (SSFE) theory. The crashworthiness of different BMCTs and MCTs was compared, and the results showed that the sixth type of bionic multi-cell tube with octagonal section (O-BMCT-6) has the best crashing performance. Then, the multiobjective optimization design of O-BMCT-6 was conducted by using non-dominated sorting genetic algorithm II (NSGA-II) and radial basis function (RBF) metamodels. The optimal O-BMCT-6 showed superior crashworthiness and could be used as an energy absorber.

Crashworthiness design for bio-inspired multi-cell tubes with quadrilateral, hexagonal and octagonal sections

This article presents a novel approach to compatibilize Kraft lignin with polyethylene that involves the use of modified poly (styrene-co-ethylene-co-butylene-co-styrene) (SEBS) as unreactive compatibilizers. As SEBS shows no compatibilizing effect on Kraft lignin-polyethylene composites, SEBS was functionalized via nitration followed by amination to obtain nitrated (SEBS-NO2) and aminated (SEBS-NH2) SEBS. The compatibilizing effects of SEBS derivatives were studied by means of morphological and mechanical analyses. The results show that SEBS-NO2 is less effective than SEBS-NH2, the later displaying comparable compatibilizing efficiency to a commercial reactive compatibilizer based on maleated polyethylene. Overall, compatibilization was found to decrease lignin particle size. Addition of SEBS-NH2 varying between 1% and 10% improved the tensile strength of composites by up to 96%, elongation at break by up to 64%, and impact strength by up to 48%. Finally, the crystallinity and density of the resulting composites were also studied. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41040.

Compatibilization of kraft lignin‐polyethylene composites using unreactive compatibilizers

This work is aimed to study the mechanical properties of basalt fibers, and their adhesion to polypropylene (PP) matrices. Single filament tensile tests were used to calculate the strength of different types of fibers, characterized by different providers and surface treatment. Single fiber fragmentation tests (SFFT) were used to calculate the critical length of the fibers, in a homopolymer PP matrix and in a maleic anhydride modified PP matrix. It was shown that the tensile strength of the fibers is not significantly influenced by the origin or the surface treatment. Only fibers without any sizing show very reduced mechanical properties. On the other hand, the tensile strength was shown to be severely dependent on the filament length. Weibull theory was used in order to calculate the fitting parameters σ0 and β, which were necessary in order to extrapolate the tensile strength to the critical length determined by SFFT. This allowed calculating the adhesion properties of the basalt fibers. It was shown that fiber–matrix adhesion is dependent on both the presence of sizing on the fiber surface, as well as on the modification of the matrix.

Mechanical properties of basalt fibers and their adhesion to polypropylene matrices

Beetles have developed the elytra that are interesting and impressive strategy for thriving in their native environments. The elytra, although formed from simple biopolymer constituents, take on many effective designs. In present work, internal structure of elytra is discussed and three bionic structures named as the bio-inspired honeycomb column thin-walled structure (BHTS) are proposed. Then the crushing behavior and energy absorption characteristics of the BHTS under axial impact loading are investigated by numerical simulation. This study reveals not only the relationship between the adding mode and energy absorption characteristics, but also the influence of column diameter on the BHTS. The findings show that the BHTS represents a significant improvement over honeycomb structures and show potential applications in the field of protective equipment.

Energy absorption characteristics of bio-inspired honeycomb column thin-walled structure under impact loading.

Compressive and flexural properties of biomimetic integrated honeycomb plates

This study investigated the mechanisms, using microscopy and strength testing approaches, by which the addition of maleic anhydride grafted high-density polyethylene (MAPE) enhances the mechanical properties of basalt fiber-wood-plastic composites (BF-WPCs). The maximum values of the specific tensile and flexural strengths are achieved at a MAPE content of 5%-8%. The elongation increases rapidly at first and then continues slowly. The nearly complete integration of the wood fiber with the high-density polyethylene upon MAPE addition to WPC is examined, and two models of interfacial behavior are proposed. We examined the physical significance of both interfacial models and their ability to accurately describe the effects of MAPE addition. The mechanism of formation of the Model I interface and the integrated matrix is outlined based on the chemical reactions that may occur between the various components as a result of hydrogen bond formation or based on the principle of compatibility, resulting from similar polarity. The Model I fracture occurred on the outer surface of the interfacial layer, visually demonstrating the compatibilization effect of MAPE addition.

https://www.mdpi.com/1996-1944/6/6/2483/pdf

Enhancement of the mechanical properties of basalt fiber-wood-plastic composites via maleic anhydride grafted high-density polyethylene (MAPE) addition

Technological Parameters and Design of Bionic Integrated Honeycomb Plates

The invention relates to a forming process of an integrated cellular board with sealed edges. The forming process of the integrated cellular board with sealed edges is characterized by comprising the following steps of: cleaning a mold, and coating an oily mold release agent on the mold surface of a male mold, and airing; spraying a dry mold release agent uniformly on the mold surface of a female mold; inserting a paraffin male mold into a female mold positioning hole; then adding fiber and resin materials by adopting different methods according to the fiber content; curing, and demoulding; and putting a test sample after demoulding into a baking oven, and fusing the paraffin male mold, thereby obtaining an integrated cellular board test sample. The integrated cellular board with sealed edges, obtained by adopting the forming process disclosed by the invention is not provided with a panel-core layer cementing surface, and the final damage is controlled by material damage; and the forming process of the integrated cellular board with sealed edges has favorable flat crush resistance and bending property, and can develop performances of the materials well.

Jianxun Liu

Papers

Compressive and flexural properties of biomimetic integrated honeycomb plates

Enhancement of the mechanical properties of basalt fiber-wood-plastic composites via maleic anhydride grafted high-density polyethylene (MAPE) addition

Technological Parameters and Design of Bionic Integrated Honeycomb Plates

Forming process of integrated cellular board with sealed edges