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To develop new, environmentally friendly prefabricated building materials, the effects of individual changes in structural parameters on the mechanical and thermal insulation properties of straw sandwich concrete beetle elytron plates (SCBEPs), i.e., sandwich plates with trabeculae constituting the core layer structure, were analyzed by ABAQUS. In addition, based on the analysis results, the structural parameters were preliminarily optimized. The results revealed the following. 1) The bearing capacity of a SCBEP is mainly controlled by deformation (i.e., the maximum deflection). The two most influencing factors on the deflection are the panel thickness T and the trabecular radius R. In contrast, although the panel area is very large, the influence of changing the panel thickness on the thermal insulation performance ranks only third. This demonstrates that the thermal bridge effect of the concrete trabeculae and edges is the primary limitation on further improvements to the thermal insulation performance of SCBEPs. 2) Based on the effects of individual changes in structural parameters on the performance of SCBEPs and their actual processing and application requirements, the structural parameters of a SCBEP with optimized mechanical properties and thermal insulation properties are determined. 3) Compared with aerated concrete wallboards, the optimized SCBEP has a higher rigidity, more compacted surface and better durability. Compared with straw concrete wallboards, the optimized SCBEP has a higher straw content and better thermal insulation performance. Thus, it provides a new avenue for the development of a new, lightweight wallboard., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

This paper discusses the progress made in China in terms of the structural colors, microstructure and mechanical properties of the beetle forewing. 1) The forewing microstructures can be classified into six phases, the first three of which are characterized by sandwich, multilayer and fiber layer structures, respectively. The fracture behaviors resulting from these three phases suggest that different scale microstructures or coupled adjacent scale microstructures can determine the macroscopic mechanical behavior of the forewing. 2) The forewing colors are derived from three features: regulation of the structural parameters of the internal optical structures, i.e., a sculpted multilayer composite two-dimensional nanopillar structure grating system; scattering on the three-dimensional surface of the bowl-shaped structure; and reversible color changes due to changes in the physical microstructure of fluffs. Their formation mechanisms were clarified, and fibers with ecological biomimetic structural colors have been developed. 3) Beetles exhibit a lightweight sectional frame structure with a trabecular core structure. Both of the joints on the left and right are concave-convex butt-joint structures with burrs, which provide an efficient docking mechanism with high intensity. The forewing of dichotoma exhibits a non-equiangular layered structure, which results in anisotropy in its tensile strength. Finally, the authors propose potential new research directions for the next 20 years., (Copyright © 2015 Elsevier B.V. All rights reserved.)