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.

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 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 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.

Effect of insulation core type on thermal conductivity of sandwich structure

2017 ◽  
Vol 52 (17) ◽  
pp. 2273-2280 ◽  
Author(s):  
Zheng Chen ◽  
Zhen Jia ◽  
Ning Yan
Keyword(s):  
Thermal Conductivity ◽  
Layer Thickness ◽  
Sandwich Structure ◽  
Core Layer ◽  
Element Model ◽  
Mineral Wool ◽  
Expanded Polystyrene ◽  
Insulation Material ◽  
Expanded Polystyrene Foam ◽  
Building Components

The influence of the layer thickness on the thermal conductivity of a sandwich structure containing an insulation material as the core layer was investigated by developing a corresponding finite element model simulating the structure. The insulation core studied included expanded polystyrene foam, polyurethane and mineral wool core. It was found that an increase in the ratio of core thickness to total surface layer thickness (shelling ratio) resulted in the decrease in the thermal conductivity of the sandwich structure. This change was significant when the shelling ratio was less than one. Regression analysis was conducted to describe the relationships among shelling ratio and thermal conductivities of the sandwich structure and each of its components. The evaluation of the thermal transmittance of the window system containing the sandwich structure used in window or other building components can be more accurate and simple.

scholarly journals The blast relief sandwich panel fixing under the explosion energy action

2021 ◽  
Vol 264 ◽  
pp. 02002
Author(s):  
Vladimir Rybakov ◽  
Olga Gracheva ◽  
Mikhail Ogurtsov ◽  
Saydiolimkhon Abdusattarhuzha ◽  
Ikbaloy Raimova
Keyword(s):  
Polymer Coating ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Mineral Wool ◽  
Excess Pressure ◽  
Explosion Energy ◽  
Galvanized Steel ◽  
Technical Solution ◽  
The Moment

This article is devoted to the assessment of the efficiency of using wall sandwich panels with mineral wool core, sheathing made of galvanized steel with a polymer coating, used as blast-relief panels. The article presents the developed seating unit for the wall sandwich panel at the moment of the explosion energy influence. As a result of the experiments carried out, when an excess pressure of no more than 3.0 kPa in the room is reached, the safety shut-off devices ensure the discharge of the displaced element, which avoids damage to the main elements of the frame. According to the results of 2 tests, the actual value of the overpressure for opening the displaced element is 2.7 kPa, which allows the discharge of the displaced element to be ensured. In the course of the study, the expediency of using blast-relief panels(BRP) in the form of wall sandwich panels was substantiated, and this technical solution was implemented at the facility with the possibility of a deflagration explosion

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.

Experimental investigation of the use of blind rivets in sandwich panels

2020 ◽  
pp. 109963622093614 ◽  
Author(s):  
Robert Studziński
Keyword(s):  
Laboratory Tests ◽  
3D Model ◽  
Sandwich Panel ◽  
Mechanical Characteristics ◽  
Mechanical Response ◽  
Experimental Studies ◽  
Sandwich Panels ◽  
Ultimate Capacity ◽  
Load Paths ◽  
Pull Out

The paper presents experimental studies of the use of blind rivets (one side connection/blind connection) in sandwich panels with polyisocyanurate foam core. The laboratory pull-out tests of the rivets from the panel facing involved two types of blind rivets (with three and four clamping arms), two types of the sandwich panel facing material (steel and laminate) and an occurrence or lack of a primer layer, which is applied between the external facing and the polyisocyanurate foam during its emerging. As a result of the laboratory tests the mechanical characteristics of the varied types of the blind connections (the equilibrium load paths, the initial and the elastic stiffnesses, the elastic and the ultimate capacity, and the ductility) as well as the failure mechanisms were obtained. The provided research data was used to verify the finite element 3D model created in the Abaqus\CAE environment. This numerical model correctly predicts the results of laboratory tests in the elastic range of the mechanical response of the blind connection with steel facing.

Thermal and Drying Cyclic Loading for Cement Based Mortars and Expanded Polystyrene Foam Layers

2012 ◽  
Vol 204-208 ◽  
pp. 3648-3651 ◽  
Author(s):  
Dimitra S. Passa ◽  
Anastasia B. Sotiropoulou ◽  
Zacharias G. Pandermarakis ◽  
George D. Mitsopoulos
Keyword(s):  
Experimental Investigation ◽  
Cyclic Loading ◽  
Hydrated Lime ◽  
Expanded Polystyrene ◽  
Polystyrene Foam ◽  
Critical Problem ◽  
Expanded Polystyrene Foam ◽  
External Insulation ◽  
Cyclic Changes

The results of the experimental investigation of the developing expansion and contraction strains of both plastering mortar and Expanded Polystyrene Foam (EPS) coatings, during thermal and drying cyclic loading are presented. The mortar used, is cement based with hydrated lime and fine marble aggregates. The EPS specimens were cut from boards of various qualities, appropriate for the external insulation of buildings. Mortar and EPS specimens were subjected to temperature cyclic changes, during which the occurring expansion and contraction strains were recorded. Based on these data, assumptions were made for the nature and the mechanism of the growing strains, in order to collect the necessary information to develop solutions for the critical problem of mortar cracking when applied over EPS insulating boards.

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.

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