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 Use of Blind Rivets in Sandwich Panels—Experimental Investigation of Static and Quasi-Cyclic Loading

Buildings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 155
Author(s):  
Robert Studziński ◽  
Katarzyna Ciesielczyk
Keyword(s):  
Experimental Investigation ◽  
Cyclic Loading ◽  
Sandwich Panel ◽  
Tensile Force ◽  
Sandwich Panels ◽  
Core Layer ◽  
Mineral Wool ◽  
Expanded Polystyrene ◽  
Eccentric Load ◽  
Pull Out

In this paper, we present an original experimental investigation on a pull-out test of a blind rivet from the external facing of sandwich panels with various core layer materials (polyisocyanurate foam, mineral wool, and expanded polystyrene). The blind rivets were subjected to an axial and eccentric tensile force introduced as static and quasi-cyclic loading. The statistical sample size was 5. The laboratory results depicted that the core layer of a sandwich panel influenced the load-displacement path of the investigated blind rivet connections, regardless of the nature of the load (static, quasi-cyclic) and the point of the load application (axial, eccentric). It was observed that the blind connection with the polyisocyanurate foam core sandwich panel was characterized by a reduction of both the capacity and the secant stiffness when compared with the blind connection with the mineral wool or the expanded polystyrene core sandwich panels. Moreover, the tested connections demonstrated that the eccentric load gave a higher flexural stiffness than the axial load and that the quasi-cyclic load did not reduce their stiffness and capacity.

Numerical Simulation of Dynamic Response of Foam Aluminum Sandwich Panel Under Impact Load

2020 ◽  
Author(s):  
Wenchao Wan ◽  
Xiaobin Li ◽  
Li Jiang ◽  
Pu Li
Keyword(s):  
Dynamic Response ◽  
Sandwich Panel ◽  
Shear Failure ◽  
Impact Load ◽  
Impact Resistance ◽  
Sandwich Panels ◽  
Core Layer ◽  
Foam Aluminum ◽  
Element Analysis ◽  
The Impact

Abstract The impact resistance of protective structure directly affects the vitality of the ship. Since the excellent energy absorption characteristics and lightweight structural forms, foamed aluminum sandwich panels have gradually replaced stiffened panels and are widely used in local structures and components of vessels. In order to improve the protective ability of the ship structure, the impact resistance of the foam aluminum sandwich panel is studied in this paper. The deformation mechanism of the foam aluminum sandwich panel under the impact of the foam aluminum projectile is simulated by the finite element analysis, and the effect of different core thickness and core strength on the dynamic response of the sandwich panel is studied. An optimized structural form is proposed for the shear failure of foam aluminum sandwich panels. The results show that the optimized structure improves the impact resistance of foam aluminum sandwich panel and the shear resistance of the intermediate core layer. The research of this paper provides reference for the optimization of foam metal sandwich structure and its application in ship protection structure.

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.

Shear-Lag Effect in Sandwich Panels With Stiffeners Under Three-Point Bending

1980 ◽  
Vol 47 (2) ◽  
pp. 383-388 ◽  
Author(s):  
K. Kemmochi ◽  
T. Akasaka ◽  
R. Hayashi ◽  
K. Ishiwata
Keyword(s):  
Strain Distribution ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Bending Rigidity ◽  
Shear Lag ◽  
Shear Lag Effect ◽  
Three Point Bending ◽  
The Core ◽  
Lag Effect ◽  
Modified Theory

In this paper, a modified theory based upon Reissner’s procedure for the shear-lag effect of the sandwich panel is presented, which includes the effects of the anisotropy of the faces and the shearing rigidity of the core. In order to verify this theory, bending experiments were performed with sandwich panels composed of a soft core, stiffeners, and orthotropic faces. It was found that the effective bending rigidity calculated from this theory was lower than that derived from the classical bending theory and that the theoretical strain distribution on the faces agreed well with the experimental results.

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.

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 Impact perforation of sandwich panels with graded hollow sphere cores: Numerical and Analytical investigations

2021 ◽  
Vol 250 ◽  
pp. 02027
Author(s):  
Ibrahim Elnasri
Keyword(s):  
Boundary Conditions ◽  
Hollow Sphere ◽  
Sandwich Panel ◽  
Peak Load ◽  
Sandwich Panels ◽  
Core Density ◽  
Plateau Stress ◽  
The Core ◽  
The Impact ◽  
Force Displacement

In this study, we numerically and analytically 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 effect of boundary conditions on the perforation resistance of the studied graded core sandwich panels was 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 un-clumping boundary conditions in the graded core sandwich panel, which is rather too hard to achieve with clumping boundary conditions. Finally, an analytical model, taken account only gradient in the quasi-static plateau stress, is developed to predict the top skin pic peak load of the graded sandwich panel.

Analysis of Sandwich Panels for an Energy Efficient and Self-Supporting Residential Roof

Solar Energy ◽  
2005 ◽  
Author(s):  
Daniel Thomas ◽  
Susan C. Mantell ◽  
Jane H. Davidson ◽  
Louise F. Goldberg ◽  
John Carmody
Keyword(s):  
Energy Efficient ◽  
Shear Failure ◽  
Oriented Strand Board ◽  
Residential Buildings ◽  
Sandwich Panels ◽  
The United States ◽  
Expanded Polystyrene ◽  
Face Sheet ◽  
Base Case ◽  
Wide Range

The structural and thermal feasibility of a self-supporting sandwich panel for energy efficient residential roof applications is assessed. The assessment is limited to symmetric sandwich panels comprising two face sheets and an insulating core. Feasible panel designs are presented for loading conditions, corresponding to southern and northern climates in the United States. The base case panel is 5.5 m long for a nominal 4.6 m horizontal span and an 8/12 roof pitch. Face sheet materials considered are oriented strand board, steel, and fiber reinforced plastic. Core materials considered are expanded polystyrene, extruded polystyrene, polyurethane and poly(vinyl-chloride) foams. A wide range of material options meet building code limits on deflection and weight and prevent face sheet fracture and buckling, and core shear failure. Panels are identified that have structural depths similar to conventional wood rafter construction. Shortening the overall panel length provides greater choice in the use of materials and decreases the required panel thickness. Suggestions for improved panel designs address uncertainty in the ability of the plastic core to withstand long term loading over the expected life of residential buildings.

scholarly journals Moisture Dry-Out Capability of Steel-Faced Mineral Wool Insulated Sandwich Panels

2020 ◽  
Vol 12 (21) ◽  
pp. 9020
Author(s):  
Kristo Kalbe ◽  
Hubert Piikov ◽  
Targo Kalamees
Keyword(s):  
Moisture Transport ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Internal Surface ◽  
Mineral Wool ◽  
Construction Time ◽  
Knowledge Based ◽  
Time Of Wetness ◽  
Dry Out ◽  
Vertical Joint

Moisture dry-out from steel-faced insulated sandwich panels has previously received little attention from researchers. This paper reports the results from laboratory tests and dynamic heat, air, and moisture transport simulations of the moisture dry-out capabilities of a steel-faced sandwich panel with a mineral wool core. Three test walls (TWs) with dimensions of 1.2 m × 0.4 m × 0.23 m were put above water containers to examine the moisture transport through the TWs. A calibrated simulation model was used to investigate the hygrothermal regime of a sandwich panel wall enclosure with different initial moisture contents and panel joint tightening tapes. The moisture dry-out capacity of the studied sandwich panels is limited (up to 2 g/day through a 30-mm-wide and 3-m-long vertical joint without tapes). When the vertical joint was covered with a vapour-permeable tape, the moisture dry-out was reduced to 1 g/day and when the joint was covered with a vapour-retarding tape, the dry-out was negligible. A very small amount of rain would be enough to raise the moisture content to water vapour saturation levels inside the sandwich wall, had the rain ingressed the enclosure. The calculated time of wetness (TOW) on the internal surface of the outer steel sheet stayed indefinitely at about 5500 h/year when vapour-retarding tapes were used and the initial relative humidity (RH) was over 80%. TOW stabilised to about 2000 h/year when a vapour-permeable tape was used regardless of the initial humidity inside the panel. A vapour-permeable tape allowed moisture dry-out but also vapour diffusion from the outside environment. To minimise the risk of moisture damage, avoiding moisture ingress during construction time or due to accidents is necessary. Additionally, a knowledge-based method is recommended to manage moisture safety during the construction process.

Numerical Study on the Response of Functionally Graded PVC Foam Core Sandwich Panels Subjected to Non-Contact Underwater Explosion

2018 ◽  
Author(s):  
Tianyu Zhou ◽  
Pan Zhang ◽  
Yuansheng Cheng ◽  
Manxia Liu ◽  
Jun Liu
Keyword(s):  
Sandwich Panel ◽  
Blast Resistance ◽  
Sandwich Panels ◽  
Underwater Explosion ◽  
Functionally Graded ◽  
Front Face ◽  
Foam Core ◽  
Compression Phase ◽  
The Core ◽  
Back Face

In this paper, the numerical model was developed by using the commercial code LS/DYNA to investigate the dynamic response of sandwich panels with three PVC foam core layers subjected to non-contact underwater explosion. The simulation results showed that the structural response of the sandwich panel could be divided into four sequential regimes: (1) interaction between the shock wave and structure, (2) compression phase of sandwich core, (3) collapse of cavitation bubbles and (4) overall bending and stretching of sandwich panel under its own inertia. Main attention of present study was placed at the blast resistance improvement by tailoring the core layer gradation under the condition of same weight expense and same blast load. Using the minimization of back face deflection as the criteria for evaluating the blast resistant of panel, the panels with core gradation of high/middle/low or middle/low/high (relative densities) from the front face to back face demonstrated the optimal resistance. Moreover, the comparative studies on the blast resistance of the functionally graded sandwich panels and equivalent ungraded ones were carried out. The optimum functionally graded sandwich panel outperformed the equivalent ungraded one for relatively small charge masses. The energy absorption characteristics as well as the core compression were also discussed. It is found that the core gradation has a negligible effect on the whole energy dissipation of panel, but would significantly affect the energy distribution among sandwich panel components and the compression value of core.

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