Core configuration and panel reinforcement affect compression properties of wood-based 2-D straight column lattice truss sandwich structure

In some applications such as roofs and walls, it is important to supply low thermal conductivity and high bending stiffness to structures. Generally, foam materials are preferred, which have low thermal conductivity. However, bending stiffness and compression properties of foam materials are low. In this study, composite tubes were inserted to the foam core material to improve the compression and bending properties of the sandwich structure. Vacuum infusion method was used to manufacture the sandwich structure. The bending and compression performance of the structures with and without composite tubes were compared. To measure the bending stiffness and compression properties of the structure, three-point bending and compression tests were conducted according to American Society for Testing and Materials (ASTM) standards. The manufacturing procedure can be easily automated and applied to large and complex shape panels. In addition, a parametric analysis was done to investigate the effect of the number of tubes and the diameter of the tubes on bending and compression stiffness of the structure. According to the test results, the samples including the composite tubes gave six times higher bending stiffness as compared to the samples without the composite tubes. As the diameter of the tubes increased the bending stiffness and the ultimate core shear strength increased. In addition, the structures including 14 mm diameter tubes had higher specific absorbed energy values under compression loading.

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Compression Properties and Its Prediction of Wood-Based Sandwich Panels with a Novel Taiji Honeycomb Core

Forests ◽

10.3390/f11080886 ◽

2020 ◽

Vol 11 (8) ◽

pp. 886 ◽

Cited By ~ 1

Author(s):

Jingxin Hao ◽

Xinfeng Wu ◽

Gloria Oporto-Velasquez ◽

Jingxin Wang ◽

Gregory Dahle

Keyword(s):

Compression Strength ◽

Sandwich Structure ◽

Mechanical Performance ◽

Compression Modulus ◽

Honeycomb Core ◽

Compression Behavior ◽

Measurement Systems ◽

Compression Properties ◽

Entire Structure ◽

Core Thickness

The transverse compression property is one of most important aspects of the mechanical performance of a sandwich structure with a soft core. An experiment, analytical method and three digital strain measurement systems were applied to investigate the compression behavior and the failure mechanism for a wood-based sandwich structure with a novel Taiji honeycomb core. The results show that the structure of the Taiji honeycomb can improve dramatically on compression strength and modulus of composite compared to that of a traditional hexagonal one. There was no obvious deflection in the transverse direction detected by the three digital images before the buckling of the honeycomb occurred. An analytical equation between the key structure parameters and properties of the composite were applied to predict its threshold stresses and modulus. The properties of the core determine the strength of the entire structure, but the compression strength decreases slightly with an elevated core thickness, and its effect on the compression modulus can be neglected. Both the surface sheets and loading speed have little impact on the compression strength and modulus, respectively.

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Evaluation Equation of the Flat Compression Properties of Corrugated Sandwich Structure

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.202 ◽

2011 ◽

Vol 189-193 ◽

pp. 202-207 ◽

Cited By ~ 1

Author(s):

Dong Mei Wang

Keyword(s):

Mechanical Properties ◽

Cell Wall ◽

Critical Stress ◽

Sandwich Structure ◽

Beam Theory ◽

Bending Moment ◽

Optimized Design ◽

Basis Material ◽

Compression Properties ◽

Compression Direction

The flat compression properties of corrugated sandwich structure are an important factor to evaluate their cushioning properties. At present, more research has been made on the mechanical properties in the cross direction (CD) and machine direction (MD), but less has been made in the flat compression direction. Selecting corrugated paperboards as samples, we analyzed the flat compression properties of the corrugated sandwich structure and explored the critical stress which is a key element for evaluating the cushioning properties based on theory and experiment. It is convenient to evaluate the cushioning properties and optimize the corrugated sandwich structure. Simplifying the corrugated structure into the struts, and referring to the bending theory of the standard beam theory, we explored the evaluating equation of the critical stress for corrugated sandwich structure by the bending moment and Euler formulas. The critical stress is in direct proportion to the elastic modulus and the thickness of the basis material. It is also closely related to the length of the corrugated cell-wall and the pasted width between the corrugated cell-wall and the linerboard. Changing the above parameters, we can change the compression resistance of the corrugated sandwich structure. The theoretical value of the critical stress of the corrugated sandwich structure is higher than the experimental value, since the mechanical properties are lost when the basis material is manufactured into corrugated sandwiches and corrugated boards. Therefore, the lost coefficient is introduced into the theoretic equation which can not only help optimize and design the corrugated sandwich structure, but also find application in optimized design of cushioning pads of corrugated sandwich structure.

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Imaging magnetic microstructure with SEMPA

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015099x ◽

1993 ◽

Vol 51 ◽

pp. 1032-1033

Author(s):

M. H. Kelley ◽

J. Unguris ◽

R. J. Celotta ◽

D. T. Pierce

Keyword(s):

Electron Microscopy ◽

Thin Films ◽

Scanning Electron Microscopy ◽

Sandwich Structure ◽

Magnetic Coupling ◽

Polarization Analysis ◽

Secondary Electrons ◽

Magnetic Microstructure ◽

Escape Depth ◽

Scanning Electron

By measuring the spin polarization of secondary electrons generated in a scanning electron microscope, scanning electron microscopy with polarization analysis (SEMPA) can directly image the magnitude and direction of a material’s magnetization. Because the escape depth of the secondaries is only on the order of 1 nm, SEMPA is especially well-suited for investigating the magnetization of ultra-thin films and surfaces. We have exploited this feature of SEMPA to study the magnetic microstrcture and magnetic coupling in ferromagnetic multilayers where the layers may only be a few atomic layers thick. For example, we have measured the magnetic coupling in Fe/Cr/Fe(100) and Fe/Ag/Fe(100) trilayers and have found that the coupling oscillates between ferromagnetic and antiferromagnetic as a function of the Cr or Ag spacer thickness.The SEMPA apparatus has been described in detail elsewhere. The sample consisted of a magnetic sandwich structure with a wedge-shaped interlayer as shown in Fig. 1.

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Enhanced performance of supercapacitors by constructing a “mini parallel-plate capacitor” in an electrode with high dielectric constant materials

Journal of Materials Chemistry A ◽

10.1039/d0ta04364h ◽

2020 ◽

Vol 8 (32) ◽

pp. 16661-16668

Author(s):

Huayao Tu ◽

Shouzhi Wang ◽

Hehe Jiang ◽

Zhenyan Liang ◽

Dong Shi ◽

...

Keyword(s):

Dielectric Constant ◽

Carbon Fiber ◽

Parallel Plate ◽

Sandwich Structure ◽

High Dielectric Constant ◽

Parallel Plate Capacitor ◽

Plate Capacitor ◽

Fiber Metal ◽

High Dielectric ◽

Mini Plate

The carbon fiber/metal oxide/metal oxynitride layer sandwich structure is constructed in the electrode to form a mini-plate capacitor. High dielectric constant metal oxides act as dielectric to increase their capacitance.

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