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In this study, a three-rib intersecting composite diamond honeycomb structure is fabricated by interlocking technology. The mechanical properties of the composite interlocked diamond honeycomb (CIDH) and corresponding sandwich structure (CIDHSS) are experimentally tested. The stiffness, strength, and failure characteristics of CIDH and CIDHSS are analyzed. The results show that CIDH has better mechanical properties than the interlocked Kagome and square honeycombs. The edge effect limits the edge compressive strength and stiffness of CIDH. Debonding is the main failure mode that limits both bending and compressive strength of CIDHSS. The reinforced plate added to the edge effectively improves the anti-debonding ability. [ABSTRACT FROM AUTHOR]

In this study, dynamically loaded sandwich panels with two different core materials and face sheets made of aluminum alloys (6061-T6) were investigated experimentally and numerically under low-velocity impact. Polypropylene, PP (C3H6)n honeycomb and extruded polystyrene foam, XPS (C8H8)n were preferred as core material. By using the contact force and kinetic energy changes, which were the impact test results of the sandwich panels, the contact and impact resistance was examined. As a result of the tests, damaged regions and permanent central displacement were determined and energy absorption capabilities were demonstrated for two different structures. The results obtained were compared with the results obtained by the open finite element method. In this study, it was shown that the face-sheet thickness of sandwich panels was an important parameter affecting the impact behavior. The behavior of the core material when the face-sheet loses its rigidity was investigated and it was found that polystyrene foam was more effective in preventing impact damage. However, it was found that using the PP honeycomb or XPS was affected the impact behavior in different points. [ABSTRACT FROM AUTHOR]

In this study, mechanical performance of octagonal structure subjected to out-of-plane compression was investigated theoretically and numerically. Theoretical derivation was carried out according to super folding element, formulas were constructed in terms of relative density, half-wave length, average force, mean stress as well as specific energy absorption (SEA). To validate, full scale numerical finite element (FE) models were created to analyze the mechanical behavior of the present structure computationally. Analytical solutions were in good agreement with computational results. Parametric study shows that different geometric configurations heavily influence the mechanical performances. Detailed comparisons between octagonal and conventional hexagonal honeycomb were performed. [ABSTRACT FROM AUTHOR]

This study presents numerical and theoretical investigation for the vertex-based hierarchical honeycomb structure subjected to axial compression. Mechanical behavior as well as predictable formulas were explored based on folded element and Minimal Energy Principle. Parametric studies were numerically conducted with different scale ratio, and the influence of wall thickness on mechanical performance was determined. Good agreement was observed between the numerical results and theoretical solutions, which validates the analytical model well. Furthermore, deformation mode comparisons were conducted between vertex-based hierarchical honeycomb and other filled-type honeycomb structures. Evident promotion on energy absorption was obtained for vertex-based hierarchical honeycomb. [ABSTRACT FROM AUTHOR]

A numerical model based on one-dimensional cell wall behavior is used to study the influence of changes in the cell wall properties on the global stiffness parameters of two-dimensional open-celled honeycombs. Following validation of results for intact microstructures, cases are considered, including regular and irregular cellular structures, structures with missing/broken cell walls, and structures with cell walls of non-uniform thickness. The influence of each of these flaws or changes in microstructure is quantified, with broken cell walls dominating changes in bulk behavior and varying cell wall thickness resulting in changes to bulk properties that can be considered negligible. [ABSTRACT FROM AUTHOR]