Mechanical behaviour of a lightweight, three-layered sandwich panel based on the raw material maize

Holzforschung ◽  
2017 ◽  
Vol 72 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Moira P. Burnett ◽  
Alireza Kharazipour
Keyword(s):  
Sandwich Panel ◽  
Core Layer ◽  
Raw Material ◽  
Furniture Industry ◽  
Wood Composites ◽  
Lightweight Construction ◽  
The Core ◽  
Mechanical And Physical Properties ◽  
Reduced Density ◽  
Material Saving

AbstractLightweight construction of composites is one of the strategies for developing material-saving panels, whereas light honeycomb boards or sandwich panels (SPs) based on foam or wood materials seem to be very promising in this context. The objective of the present work was the development of an SP with a reduced density based on nearly 100% expanded maize granular in the core layer, which was combined with 3 mm thin and stiff poplar plywood as face materials. In focus were mechanical and physical properties of the SPs, which should be applicable in the furniture industry and competitive with conventional wood composites such as fibreboards or particle boards.

scholarly journals Testing of Precast Lightweight Foamed Concrete Sandwich Panel with Single and Double Symmetrical Shear Truss Connectors under Eccentric Loading

2011 ◽  
Vol 335-336 ◽  
pp. 1107-1116 ◽  
Author(s):  
Noridah Mohamad ◽  
Hilmi Mahdi Muhammad
Keyword(s):  
Sandwich Panel ◽  
Core Layer ◽  
Surface Strain ◽  
Structural Performance ◽  
Eccentric Load ◽  
Composite Action ◽  
The Core ◽  
Steel Rebar ◽  
Foamed Concrete ◽  
Single Shear

This paper reports the structural behavior of precast lightweight foamed concrete sandwich panel, PLFP, subjected to eccentric loading. An experiment was conducted to investigate the structural performance of PLFP under this load. Two PLFP panels, PE-1 and PE-2 were cast with 2000 mm in heights, 750 mm in width and 100 mm in thickness. The thickness of the wall is actually a combination of three layers. Skin layers were cast from lightweight foamed concrete while the core layer is made of polystyrene. The skin layers were connected to each other by 9 mm steel shear truss connector which were embedded through the layers. Panel PE-1 was strengthened with single diagonal shear truss connectors made of 6 mm steel rebar while panel PE-2 was strengthened with symmetrical diagonal shear truss connectors of similar steel diameter. Both panels were tested under eccentric load till failure. The results showed that panel with symmetrical double truss connectors, PE-2, is able to sustain higher load compared to panel with single shear truss connector. The load-deflection profiles indicate that both panels achieved certain degree of composite action especially during the later stage of loading where the wythes tend to move in the same direction until they reached failure. The load-strain curves for both panels highlight the inconsistent distribution of surface strain along the height of panels. The overall trend of the strain curves show that they are under compression.

scholarly journals Blast Test and Failure Mechanisms of Soft-Core Sandwich Panels for Storage Halls Applications

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 70 ◽  
Author(s):  
Robert Studziński ◽  
Tomasz Gajewski ◽  
Michał Malendowski ◽  
Wojciech Sumelka ◽  
Hasan Al-Rifaie ◽  
...  
Keyword(s):  
Sandwich Panel ◽  
Shear Failure ◽  
Failure Mechanisms ◽  
Sandwich Panels ◽  
Core Layer ◽  
Mineral Wool ◽  
Expanded Polystyrene ◽  
Blast Load ◽  
Steel Columns ◽  
The Core

In this paper, an experimental investigation is presented for sandwich panels with various core layer materials (polyisocyanurate foam, mineral wool, and expanded polystyrene) when subjected to a justified blast load. The field tests simulated the case for when 5 kg of trinitrotoluene (TNT) is localized outside a building’s facade with a 5150 mm stand-off distance. The size and distance of the blast load from the obstacle can be understood as the case of both accidental action and a real terroristic threat. The sandwich panels have a nominal thickness, with the core layer equal 100 mm and total exterior dimensions of 1180 mm × 3430 mm. Each sandwich panel was connected with two steel columns made of I140 PE section using three self-drilling fasteners per panel width, which is a standard number of fasteners suggested by the producers. The steel columns were attached to massive reinforced concrete blocks via wedge anchors. The conducted tests revealed that the weakest links of a single sandwich panel, subjected to a blast load, were both the fasteners and the strength of the core. Due to the shear failure of the fasteners, the integrity between the sandwich panel and the main structure is not provided. A comparison between the failure mechanisms for continuous (polyisocyanurate foam and expanded polystyrene) and non-continuous (mineral wool) core layer materials were conducted.

scholarly journals Oversized Planer Shavings for the Core Layer of Lightweight Particleboard

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1125
Author(s):  
Jakob Gößwald ◽  
Marius Cătălin Barbu ◽  
Alexander Petutschnigg ◽  
Ľuboš Krišťák ◽  
Eugenia Mariana Tudor
Keyword(s):  
Mechanical Properties ◽  
Internal Bond ◽  
Urea Formaldehyde ◽  
Core Layer ◽  
Solid Wood ◽  
Raw Material ◽  
Modulus Of Rupture ◽  
Low Density ◽  
The Core ◽  
Adhesive Application

Planer shavings (PS) are side-products generated during the processing of solid wood, typically used for heating, packaging, or insulation purposes. PS has been used for decades in particleboard manufacture, particularly in the core layer. The aim of this research is to investigate the use of PS with a length over 4 mm in low-density one-layer particleboard manufacturing with a thickness of 10 mm, as an option to reduce the raw material demand for wood-based panels. Correlations towards the mechanical properties of the particleboards, fabricated at a density of 475 kg/m3, could be drawn by analyzing the effects of different urea-formaldehyde adhesive contents (6%, 9%, and 12%). Two methods of adhesive application (pouring and spraying) and two types of blending of PS with adhesive (plowshare mixer and drum mixer) were investigated, with the aim that PS will have controlled resin application. The difference between the adhesive application methods was examined by analyzing the mechanical properties as an internal bond, modulus of rupture, and modulus of elasticity as well as indirectly by visualizing the adhesive distribution by adding a green pigment to the adhesive before application. PS demonstrated reduced bending properties in comparison with the EN 312 standard requirements of particleboards for internal use in dry conditions (type P2), due to the low density. The internal bond strength in the case of the particleboard without pigment application (up to 0.5 N/mm2) was higher compared to the P2 requirements (0.4 N/mm2), and significantly lower (0.15 N/mm2) in combination with the pigment (2.5% based on the board weight, compared to 0.1%, specific for such industry applications), but still superior to the values of the reference panel manufactured with wood particles.

scholarly journals Preparation and application of carbon and hollow TiO2 microspheres by microwave heating at a low temperature

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 200-209
Author(s):  
Caiyun Zhang ◽  
Chunhong Li ◽  
Bolin Ji ◽  
Zhaohui Jiang
Keyword(s):  
Low Temperature ◽  
Microwave Heating ◽  
Raw Material ◽  
Carbon Microspheres ◽  
Microwave Assisted ◽  
The Core ◽  
Good Crystallinity ◽  
Carbon Core ◽  
Microwave Assisted Method ◽  
Uniform Particle Size

Abstract A fast, simple, and energy-saving microwave-assisted approach was successfully developed to prepare carbon microspheres. The carbon microspheres with a uniform particle size and good dispersity were prepared using glucose as the raw material and HCl as the dehydrating agent at low temperature (90°C) in an open system with the assistance of microwave heating. The carbon microspheres were characterized by elemental analysis, XRD, SEM, FTIR, TG, and Raman. The results showed that the carbon microspheres prepared under the condition of 18.5% (v/v) HCl and heating for 30 min by microwave had a narrow size distribution. The core–shell structure of the carbon core and TiO2 shell was prepared with (NH4)2TiF6, H3BO3 using the microwave-assisted method. The hollow TiO2 microspheres with good crystallinity and high photocatalytic properties were successfully prepared by sacrificing the carbon microspheres.

scholarly journals A numerical study of the impact perforation of sandwich panels with graded hollow sphere cores

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110094
Author(s):  
Ibrahim Elnasri ◽  
Han Zhao
Keyword(s):  
Boundary Conditions ◽  
Hollow Sphere ◽  
Sandwich Panel ◽  
Numerical Study ◽  
Sandwich Panels ◽  
Hopkinson Bar ◽  
Core Density ◽  
The Core ◽  
The Impact ◽  
Force Displacement

In this study, we numerically investigate the impact perforation of sandwich panels made of 0.8 mm 2024-T3 aluminum alloy skin sheets and graded polymeric hollow sphere cores with four different gradient profiles. A suitable numerical model was conducted using the LS-DYNA code, calibrated with an inverse perforation test, instrumented with a Hopkinson bar, and validated using experimental data from the literature. Moreover, the effects of quasi-static loading, landing rates, and boundary conditions on the perforation resistance of the studied graded core sandwich panels were discussed. The simulation results showed that the piercing force–displacement response of the graded core sandwich panels is affected by the core density gradient profiles. Besides, the energy absorption capability can be effectively enhanced by modifying the arrangement of the core layers with unclumping boundary conditions in the graded core sandwich panel, which is rather too hard to achieve with clumping boundary conditions.

scholarly journals Spin-Orbit Matrix Elements for a Combined Spin-Flip and IP/EA Approach

2020 ◽  
Author(s):  
Oinam Meitei ◽  
Shannon Houck ◽  
Nicholas Mayhall
Keyword(s):  
Mean Field ◽  
Coupling Constants ◽  
Basis Set ◽  
Reduced Density Matrix ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Matrix Elements ◽  
Dynamical Correlation ◽  
The Core ◽  
Reduced Density

We present a practical approach for computing the Breit-Pauli spin-orbit matrix elements of multiconfigurational systems with both spin and spatial degeneracies based on our recently developed RAS-nSF-IP/EA method (JCTC, 15,<br>2278, 2019). The spin-orbit matrix elements over all the multiplet components are computed using a single one-particle reduced density matrix as a result of the Wigner-Eckart theorem. A mean field spin-orbit approximation was used to account for the two-electron contributions. Basis set dependence as well as the effect of including additional excitations is presented. The effect of correlating the core and semi-core orbitals is also examined. Surprisingly accurate results are obtained for spin-orbit coupling constants, despite the fact that the efficient wavefunction approximations we explore neglect the bulk of dynamical correlation.<br>

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