• International conference on construction engineering and project management
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• 2022.06a
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• pp.436-442
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• 2022

Hurricanes and tornadoes are the most destructive natural disasters in some central and southern states. Thus, storm shelters, which can provide emergency protections for low-rise building residents, are becoming popular nowadays. Both FEMA and ICC have published a series of manuals on storm shelter design. However, the authors found that the materials for related products in the market are heavyweight and hard to deliver and install; renovations are necessary. The authors' previous studies found that lightweight and high-performance composite materials can withstand extreme wind pressure, but some building codes are designated in wind-borne debris areas. In these areas, wind debris can reach greater than 100 mph speed. In addition, the impact damage on the composite materials is an increasing safety issue in many engineering fields; some can cause catastrophic results. Therefore, studying composite structures subjected to wind debris impact is essential. The finite element models are set up using the software Abaqus 2.0 to conduct the simulations to observe the impact resistance behavior of the carbon fiber composite sandwich panels. The selected wood debris models meet the FEMA requirements. The outcome of this study is then employed in future lab tests and compared with other material models.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.121-124
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• 2005

This paper was about experimental test properties by mechnical joint of CF1263/Epoxy Al honeycomb panels. In case of mechanical joint using screw, nut shall be secured over than minimize third screw pitch. In case of insert backsheet for increase of joint force, increase weight for assemble by screw pitch. In case of insert backsheet with CF1263/Epoxy, predominant save weight and minimazer of displacement by tensile weight moreover predominant strength. In case of mechanical joint by rivet, rivet of Monobolt has over-hole in hole of CF1263/Epoxy but rivet of PROTRUDING has predominant of mechanical joint.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.105-110
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• 2002

In this study, a MMA modified polymer mortal sandwich panels was developed : Core was made with the MMA modified polymer mortar whose compressive strength was about 1020 kgf/cm$^2$, and both facings were made with the glass fiber reinforced plastics (GFRP). The results showed that the strain energies increased 20-33 times, respectively, as the thicknesses of facings increased from 1.50 to 2.76 mm with fixing the core thickness to constants (30-50 mm). On the other hand, these values showed a tendency of decrease as the core thickness increased regardless of thickness of facings. A set of basic data for the structural analysis could be provided by investigating the correlations, within the scope of this research, between the resisting moment and the thicknesses of core and facings.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.126-133
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• 1997

For each construction material used, there is certain theoretical limit in sizes. For tall building construction, the reduction in slab weight is the first step to take in order to break such size limits. In this paper, the feasibility of such objective is proven and given by numerical analysis result. For a typical building slab, both concrete and advanced composite sandwich panels are considered. The concrete slab is treated as a special orthotropic plate to obtain more accurate result. For each panel, the deflection under the dead and live loads is compared, since both tensile and compressive strengths of the composites are far more higher than those of concrete. All types of sandwich panels considered, except one case, have weights less than one tenth of that of reinforced concrete slab, with deflections less than that of the concrete slab. The cost analysis result and manufacturing methods will be reported later.

• Fire Science and Engineering
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• v.31 no.3
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• pp.79-87
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• 2017

Sandwich panels which are having the both sides are bonded with a heat insulating material with an iron plate are used as factories, warehouse structures as advantages of convenience in construction at economic efficiency of material cost. However, in a panel structure constructed by continuous joining of sandwich panels, a joint portion where a panel and a panel are connected is generated. The joint part is a part which is easily vulnerable to fire because flames easily flow into the melting and deformation of the iron plate during fire. The flames flowing into the panel induce diffusion of fire by rapid burning, causing damage of human life and property. In this research, we developed a flame spread prevention plate to prevent spreading of sandwich panel. This is an improvement of the workability by the anti-spreading construction method of the existing previous research, it can be applied independently to the connecting part where the panel and the panel are coupled, designed to prevent inflow and spreading of flame did. The actual fire test of the test method of KS F ISO 13784-1 of the sandwich panel specimen was conducted and the burning behavior corresponding to the presence or absence of application of the flame spread prevention plate was grasped at the panel connection part and its effect was measured. Inserting a fire spreading plate into the test result panel connecting part is measured by delaying the flashover, prevention of collapse of the specimen, and temperature rise of the opening, effectively improving the fire safety of the panel structure It was confirmed as a method that can be secured. It is judged that panel structure will contribute to ensuring fire safety by applying the fire spread prevention construction method of various methods ensuring the workability and economy of panel connection vulnerable to fire.

• Composites Research
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• v.19 no.1
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• pp.9-14
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• 2006

Experimental investigation on heat transfer ratio was firstly performed with three types of sandwich panels such as the Carbon/Epoxy Skin-Aluminum Honeycomb and Balsa Core Sandwich Panel of 37mm thickness, the Carbon/Epoxy Aluminum Skin-Honeycomb Core Sandwich Panel of 57mm thickness (including insulator) and the Carbon/Epoxy Skin-Aluminum Honeycomb Core Sandwich Panel of 37mm thickness based on the KS F 2278:2003(Insulation test method of windows). In additional to this investigation, experimental tests were also done for evaluation of heat transportation ratio with the Aluminum Skin- Aluminium Honeycomb Sandwich Panels of 27mm and 35mm thickness, and Aluminum Skin-Foaming Aluminum Sandwich Panel of 27mm thickness by the KS F2277:2002 (Insulation measuring method of construction component-Calibration heat box method or protective heat box method). In this study, it was found that the larger net heat transfer cross sectional area between the skin and the sandwich core is given, the higher heat transportation ratio occurs. It was also found that the hybrid type insulation had better insulation characteristics compared to the non-hybrid type insulation.

• Structural Engineering and Mechanics
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• v.47 no.5
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• pp.623-641
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• 2013

The fiber-reinforced polymer (FRP) composite panel, with the benefits of light weight, high strength, good corrosion resistance, and long-term durability, has been considered as one of the prosperous alternatives for structural retrofits and replacements. Although with these advantages, a further application of FRPs in bridge engineering may be restricted, and that is partly due to some unsatisfied thermal performance observed in recent studies. In this regard, Kansas Department of Transportation (DOT) conducted a field monitoring program on a bridge with glass FRP (GFRP) honeycomb hollow section sandwich panels. The temperatures of the panel surfaces and ambient air were measured from December 2002 to July 2004. In this paper, the temperature distributing behaviors of the panels are firstly demonstrated and discussed based on the field measurements. Then, a numerical modeling procedure of temperature fields is developed and verified. This model is capable of predicting the temperature distributions with the local environmental conditions and material's thermal properties. Finally, a parametric study is employed to examine the sensitivities of several temperature influencing factors, including the hollow section configurations, environmental conditions, and material properties.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.8
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• pp.798-805
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• 2010

Whole composite structure small class (150kg) satellite, STSAT-3, was initially developed in Korea. The structure does have aluminum frames that support the structure, and it is composed of only composite sandwich panels. A number of electronic boxes and mechanical apparatus will be shielded within the compartments built up by the composite panels. This study focused on the random vibration responses of the satellite. For this objective, vibration tests and analyses have been successfully performed with respect to STM (structure and thermal model) of the satellite. Additionally, through the experiment and theoretical analyses, the both results' accuracy was verified by comparison each other.

• Structural Engineering and Mechanics
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• v.68 no.6
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• pp.721-733
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• 2018

The modal frequency responses of functionally graded (FG) sandwich doubly curved shell panels are investigated using a higher-order finite element formulation. The system of equations of the panel structure derived using Hamilton's principle for the evaluation of natural frequencies. The present shell panel model is discretised using the isoparametric Lagrangian element (nine nodes and nine degrees of freedom per node). An in-house MATLAB code is prepared using higher-order kinematics in association with the finite element scheme for the calculation of modal values. The stability of the opted numerical vibration frequency solutions for the various shell geometries i.e., single and doubly curved FG sandwich structure are proven via the convergence test. Further, close conformance of the finite element frequency solutions for the FG sandwich structures is found when compared with the published theoretical predictions (numerical, analytical and 3D elasticity solutions). Subsequently, appropriate numerical examples are solved pertaining to various design factors (curvature ratio, core-face thickness ratio, aspect ratio, support conditions, power-law index and sandwich symmetry type) those have the significant influence on the free vibration modal data of the FG sandwich curved structure.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.12 s.105
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• pp.1361-1369
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• 2005

Based on a full layerwise displacement shell theory, the nitration and damping characteristics of cylindrical sandwiched panels with viscoelastic layers are investigated. The transverse shear deformation and the normal strain of the cylindrical hybrid panels are fully taken into account for the structural damping modelling. The present finite element model Is formulated by using Hamilton's virtual work principle and the cylindrical curvature of hybrid panels is exactly modeled. Modal loss factors and frequency response functions are analyzed for various structural parameters of cylindrical sandwich panels. Present results show that the full layerwise finite element method can accurately predict the vibration and damping characteristics of the cylindrical hybrid panels with surface damping treatments and constrained layer damping.