Sandwich Panels Research Articles

The analysis and prediction of nonlinear damping characteristics of partially filled all-composite honeycomb-core sandwich panels

In this paper, a comprehensive nonlinear damping prediction model of partially filled all-composite honeycomb-core sandwich panels (PF-ALHCSP) is proposed. Based on integrating high-order shear theory and Hamilton's principle, a theoretical model of the structure is established. Then, the energy equations are deduced by the finite element method. Thus, the nonlinear damping is obtained by the introduced complex modulus method. To validate the overall performance of the material and the accuracy of the theoretical model, the corresponding specimens are fabricated and a self-designed vibration testing platform is established. The results indicate that this material exhibits higher damping capacities compared to traditional metals or composite materials. To further enhance the material optimization, in conjunction with the proposed theoretical model, an investigation on the influence of three variables, filler density, honeycomb cell thickness, and panel thickness, on the structural damping characteristics across three different filling ratios is conducted. The proposed novel composite material and nonlinear damping prediction model can be adjusted according to practical applications for structural parameters, meanwhile effectively reducing material replacement frequency. The theoretical model provides a relatively accurate computational method for studying the nonlinear damping characteristics of partially filled foam honeycomb core sandwich structures, offering valuable insights for research in this field.

Lightweight design optimization of two-layer corrugated cored sandwich panel under blast loading using surrogate-assisted different evolution for mixed-integer variables

The sandwich structure stands out as an ideal candidate for blast-resistant armor due to its excellent performance, of which the optimization typically involves time-consuming finite element simulations. Recently, surrogate models have emerged as a promising alternative for time-consuming simulations to accelerate the optimization process of blast-resistant sandwich panels. However, existing methods are limited to optimizing a handful of continuous variables, and often focus on single-layer core sandwich panels. This article introduces a novel constrained optimization model for Two-layer composite Corrugated cored Sandwich Panels (TCSP). The design variables include not only continuous variables such as structural component heights and thicknesses, but also integer variables such as material selection and the number of core unit-cells. To tackle this complex optimization problem with mixed-integer variables, a surrogate-assisted differential evolution (SADE-TCSP) is proposed. This algorithm utilizes the predictive capabilities of surrogate models to guide the optimization process towards a high-quality feasible solution within a very limited computational budget. In order to validate our approach, an optimization framework integrating MATLAB and ABAQUS is developed to conduct numerical experiments. Experimental results show that the proposed method can achieve a 51.04 % reduction in total structural mass while satisfying performance constraints, which is significantly better than existing methods.

Response of circular type sandwich panel using JUCO-glass fiber with PU foam under three-point bending loading

In this study, a circular type honeycomb sandwich panel using natural JUCO and synthetic woven glass fiber was fabricated, and the bending properties like bending strength, modulus of rupture (MOR), and modulus of elasticity (MOE) were evaluated. Polyurethane (PU) foam was injected into the core structure to improve the bending strength. The orientation of jute and cotton fiber was varied to investigate the best stiffness and strength. In addition, twill-type JUCO fiber mat and synthetic woven glass fiber were also used to fabricate the circular type honeycomb sandwich panel. Finite element modeling was undertaken to validate the experimental results. Prior to the finite element analysis, a tensile test was carried out to determine the boundary conditions. Injecting polyurethane foam into the honeycomb core does not show any significant impact on bending properties. However, the deformation rate increased considerably by adding PU foam in the core structure. According to the results, honeycomb sandwich panels made of woven glass fiber with PU foam exhibited more homogenous deflection and bending compliance compared with others.

Nonlinear vibration characteristics of all-composite honeycomb-core sandwich panel: Theoretical and experimental investigation

Nonlinear vibration characteristics of all-composite honeycomb-core sandwich panel: Theoretical and experimental investigation

Analysis of the ballistic impact on sandwich panel: influence of attack angle and target location in structure–bullet interaction

Analysis of the ballistic impact on sandwich panel: influence of attack angle and target location in structure–bullet interaction

Global buckling response of sandwich panels with additively manufactured lattice cores

This paper deals with the analytical and numerical global buckling analysis of rectangular sandwich plates utilized AlSi10 Mg in both facesheets and lattice cores. In this study, six different strut-based lattice core models are designed. Additionally, the buckling resistance of lattice panels is compared with a typical honeycomb panel. Analytical studies were carried out using Kirchoff plate theory (CLPT), first-order shear deformation theory (FSDT) coded on MATLAB and finite element (FE) analyses in Abaqus. In the theoretical approaches, the Navier solution is derived for sandwich plates with simply supported boundary conditions at all edges. In the FE analyses, validated homogenized lattice structures models were used to avoid excessive numbers of elements and to save computational time. The parametric effects of side-to-thickness ratio, and different designed core cells on global buckling responses are investigated. As a result of comparing the analytical results with the FE model, a good agreement is obtained, and it is found that analytical buckling analyses FSDT can be used within certain size limits for the global buckling analysis of lattice core sandwich structures.

Development of an electromagnetic compatible composite-insert embedded in a double-curved sandwich panel

Composite sandwich structures, which are widely employed in engineering structures, require a multitude of inserts. In certain instances, the necessity for a specialized insert arises from the unique characteristics of a particular application. In applications such as weather radar radomes, double-curved sandwich panels should be designed with electromagnetic (EM) transparency as a primary objective. The use of metal inserts should be restricted to the absolute minimum. Given the limitations of using metal materials to protect against EM radiation and the need to enhance the load-bearing capacity of the joint against pull-out loads, a composite insert has developed as an innovative solution. In this study, a composite insert of a double-curved sandwich dome has been developed using silica nanoparticles, and its mechanical strength against pull-out load has been evaluated through both experimental and numerical analysis. The strength results obtained have been compared with analytical estimates. Additionally, the buckling of the double-curved sandwich dome against a wind speed of 220 km/h has been investigated numerically. The critical buckling load for wind loading for the full-scale sandwich radome was estimated to be 16,303 N. According to the numerical results obtained with the Abaqus finite element (FE) software, the maximum pull-out force applied to the connection area is approximately 10.7 kN. A parametric study of geometric variables and experimental results showed that it is possible to achieve a stronger composite insert (by 1 wt % nano silica particles) by 20.7% lighter and 102.65% more bearing capacity.

Numerical study on structured sandwich panels exposed to spherical air explosions

There is a need to develop innovative protective shield structures to withstand extreme loads, such as impact and blast loading. Sandwich structures that absorb significant kinetic energy as strain energy through plastic deformation offer superior protection. This study conducts a numerical analysis of structured sandwich protective structures subjected to airblast loads using finite element modeling. First, an experimental result from the literature was used to validate and verify finite element models of an architected sandwich structure modeled in Abaqus/Explicit software. Second, parametric studies were conducted on sandwich structures with additional layers of insert plates and newly proposed core topologies for viable shield protection against airblast loading. The finite element analysis results indicated that, under the same impulsive load, the control sandwich panel exhibited higher kinetic energy, demanding a proportionally larger internal energy. Conversely, sandwich structures with additional inner core insert plates dissipated the imposed kinetic energy more efficiently, due to the inelastic plastic deformation of the proposed core configurations. Moreover, the energy absorption capacity and back sheet displacement time-history were significantly improved by dense-hierarchical inner core configurations. Additionally, the parametric study analysis showed that increasing the number of insert plates and designing the core topology of cellular walls to be redundant, dense-hierarchical, and braced against buckling significantly reduced core collapse mechanisms such as folding, buckling, and crushing. However, despite these benefits, a reversed effect on the areal specific energy absorption index was observed.

To Study the Construction Techniques for Slum Rehabilitation In Metro Cites

With increasing urbanization, the need for adequate affordable shelter also increases. Housing shortage is one of the major challenges faced in developing countries like India. It is imperative to provide housing that caters to all income groups with special focus on the low and middle income groups. In order to provide low cost housing, it is essential to adopt innovative sustainable technologies which are affordable, fast track, cost effective, durable as well as environment friendly. This seminar discusses emerging innovative technologies that can be adopted in the country to lower housing construction cost and help in provision of mass affordable housing. Some of the technologies discussed are Tunnel form, Sismo building technology, Light Gauge Steel Framed Structural technology, Precast Sandwich Panel technology etc. These technologies are reviewed on various parameters like local availability, affordability, energy efficiency, structural stability, quality, speed, cost effectiveness, eco friendliness and suitability for high rise construction. The advantages and limitations of the technologies are also mentioned. The seminar highlights the potential barriers for adoption of these technologies in the Indian urban scenario and methods which can be employed to overcome those barriers in order to provide affordable housing for the low and middle income groups. Fast track construction is very much essential for the mass housing projects like slum rehabilitation . For this rapid wall technique can be best option for construction

Development and characterization of a novel AA6061 composite reinforced with titanium aluminide via friction stir processing

Current research work emphasizes on the development of particulate titanium aluminide (TiAl), an intermetallic class of material, through mechanical alloying (MA) from elemental powders and usage of same as reinforcement in AA6061 aluminum matrix to enhance its mechanical and tribological performance. TiAl, being a light weight, strong and abrasion-resistant material, is found to be a suitable candidate to replace dense ceramic-based reinforcements in aluminum composite. Friction stir processing (FSP), a well-established surface severe plastic deformation tool, is used to develop the composite in this study. Several strategies on improving the stirring action and particle distribution during FSP is employed and their scientific effect is studied in detail. Microstructural evolution was studied through scanning electron microscopy (SEM) combined with electron backscattered diffraction (EBSD) analysis which revealed uniform particle distribution of reinforcement in the friction stir processed (FSPed) zone with 88.23 % reduction in grain size of composite as compared to base material. Hardness studied showed an increase in the hardness by 33 % for composite material as compared to un-reinforced FSPed material, showing the positive effect of reinforcement alone on the mechanical strength of the material. Tensile results showed an improvement in yield tensile strength from 156 MPa in base to 186.8 MPa in the composite material without significant compromise in the ductility 26.86 % for composite and 28.14 % for base. Mechanisms aiding uniform particle distribution, and the reasons for improvement in mechanical performance of the developed composite is discussed in detail with the help of microstructural studies and post-deformation fractograph.

Magnetic solid phase extraction of methiocarb pesticide from food samples prior to HPLC analysis with magnetic activated carbon cloth/zinc aluminate (magnetic ACC@ZnAl2O4) composite

Methiocarb is a carbamate pesticide and is widely used due to its short lifetime but is a health concern due to its toxicity. To address this challenge, a novel nano-sorbent (zinc aluminate hybrid doped onto a magnetic activated carbon cloth (magnetic ACC@ZnAl2O4)) was synthesized. The characterization of the composite was done using FTIR spectroscopy, SEM, XRD, and EDX. The synthesized composite was then employed for the efficient extraction of methiocarb from food samples. Under the optimum conditions of (pH: 7.0, vortex time: 0.5 min, adsorbent dose: 5 mg, initial volume of sample: 50 mL, volume of eluent: 1.0 mL), quantitative recovery values of methiocarb in food samples were obtained (80–114%). This method impresses with its exceptional sensitivity, achieving incredibly low detection (LOD: 20 µg L−1) and quantification (LOQ: 67 µg L−1) limits for methiocarb. Its efficiency is equally impressive, with high values of preconcentration factor (PF: 50) and enhancement factor (EF: 49.4), ensuring accurate and reliable analysis with a low value of relative standard deviation (RSD: 4.8%). The method’s impressive selectivity, evident in its minimal interference from other pesticides, paves the way for reliable methiocarb analysis in food samples.

Numerical Investigation on Dynamic Response of Carbon Fiber Honeycomb Sandwich Panels Subject to Underwater Impact Load

This study investigates the dynamic response and failure mechanisms of carbon fiber honeycomb sandwich structures under underwater impact loads using finite element numerical simulation. The geometric modeling was performed using HyperMesh, and the dynamic response simulations were carried out in ABAQUS, focusing on honeycomb core configurations with varying edge lengths, heights, and gradient forms. The Hashin damage model was employed to describe the damage evolution of the composite materials. The simulation results revealed that the dynamic response was significantly influenced by the initial shock wave pressure and the geometrical parameters of the honeycomb cells. Larger cell-edge lengths and heights generally resulted in improved energy absorption and reduced rear panel displacement. Among the different configurations, interlayer gradient honeycomb structures demonstrated superior impact resistance compared to homogeneous and in-plane gradient structures, particularly under higher initial shock wave pressures. These findings contribute to optimizing the design of carbon fiber honeycomb sandwich structures for enhanced impact resistance in relevant applications.

Proposing novel body-centered cubic lattice core sandwich panels as satellite structure

In the present paper, a comparative study on the load-bearing as well as shielding performance against hypervelocity impact of space debris of sandwich panels with body-centered cubic lattice core is performed numerically in order to evaluate their eligibility to be utilized as the satellite structure. To this end, four types of body-centered cubic lattice structures, with similar areal densities which are assumed to be made of 5A06 aluminum alloy, including BCC, BCCz (BCC reinforced in Z direction), and also BCCz-I and BCCz-II were considered. Whipple shield structure of same material and areal density was also investigated in order to justify the necessity of lattice structures application, especially in protection field. The present study simulates hypervelocity impact of a spherical projectile with 2 mm diameter, represented the space debris, collides with the structures at the velocity range of 2–6 km/s. Current numerical simulation process accuracy and efficiency were verified through comparing its obtained data based on simulating a problem had been investigated at a valid experimental study to the data proposed by the mentioned research. BCCz-II structure which is newly proposed at this study provided outstanding shielding and load-bearing capabilities in comparison to other structures. Furthermore, the detailed effects of projectile impact location and a middle structure placed plate on the protection performance were investigated and the mentioned items were found to have crucial impact on the structure shielding performance.

Designing a Stiffener Layout that Resists the Wrinkling Behaviors of Sandwich Panels

Designing a Stiffener Layout that Resists the Wrinkling Behaviors of Sandwich Panels

Investigation of the Mechanical Properties of Composite Honeycomb Sandwich Panels after Fatigue in Hygrothermal Environments.

Since carbon fibre composite sandwich structures have high specific strength and specific modulus, which can meet the requirements for the development of aircraft technology, more and more extensive attention has been paid to their residual mechanical properties after subjecting them to fatigue loading in hygrothermal environments. In this paper, the compression and shear characteristics of carbon fibre-reinforced epoxy composite honeycomb sandwich wall panels after fatigue in hygrothermal environments are investigated through experiments. The experimental results show that under compressive loading, the load required for the buckling of composite honeycomb sandwich wall panels after fatigue loading in hygrothermal environments decreases by 25.9% and the damage load decreases by 10.5% compared to those at room temperature. Under shear loading, the load required for buckling to occur is reduced by 26.2% and the breaking load by 12.2% compared to those at room temperature.

The impact of various metals on the performance of TNT

Abstract In blast applications, investigations involving energetic materials and various reactive metals are conducted. Some examples of such metals include copper, aluminum, and magnesium aluminum composite (magnalium). On the other hand, aluminum’s cheap price, good dependability, and very high heat of combustion make it the most widely used gasoline additive. In this study, lab-scale formulations of metalized high explosives were made using TNT and various metallic fuels (Cu, Mg-Al, and Al). Then, using DSC and performance parameters measured by ballistic mortar, the researchers evaluated the explosives’ workability and destructive effect, as well as the impact of the metal fuels on TNT’s thermal behavior (Brisance by Kast). Results showed that the melting point of TNT shifted to lower temperatures due to the various metallic fuels (Cu, Al, Mg-Al). The Al with TNT sample also had the greatest brightness of the ones we looked at.

Thermal performance assessment of sandwich wall panel fabricated with polyurethane foam and natural husk

The demand for enhancing thermal efficiency in building construction has accelerated the evolution of sandwich wall panels in recent years. In this study, the novel sandwich panel is developed using Polyurethane (PU) as core and PU replaced with Rice husk (RH) and Coconut Husk (CH) at varying percentage (10, 20, 30, 40 and 50 %) with calcium silicate board as outer material. Dimension of sandwich panel is 30 × 30 cm with 3 cm as a core thickness is tested for compressive strength. The panel owing highest compressive load with combination of Polyurethane foam Coconut Husk panel at 20 % (PUC3–20 %) and polyurethane foam Rice husk panel at 30 % (PUR3–30 %) was taken further for thermal analysis. The temperature study was carried out on a prototype model using IR thermographic camera showing the temperature difference of indoor and outdoor of the sandwich panel. The PUR3–30 % shows the thermal conductivity of 0.28 w/mk and the difference of thermal heat flux was 10.42 W/m2. Regression analysis was carried out to validate the experimental results and the correlation accuracy of R2 > 0.90 was obtained. A residential building (G+3) was created in Autodesk Revit to conduct an energy analysis audit, where all the data of fabricated sandwich panel was added as new material and the analysis was carried out in green building studio. The annual energy and annual fuel end use for Heating Ventilation and Air Conditioning (HVAC) has been decreased by 3.5 and 4.5 % using PUC3–20 % and PUR3–30 % panels compared to the base material.

High-temperature effect on continuous glass fiber reinforced polypropylene multilayer composite and corrugated sandwich panels

The high-temperature mechanical behaviors of Multi-Layer Composite Panels (MCP) and Corrugated Sandwich Panels (CSP) of Continuous Glass Fiber-Reinforced Polypropylene (CGFRPP) are critical for their application in aerospace fields, which have been rarely mentioned in previous studies. High-temperature quasi-static tensile and compression tests on CGFRPP MCP are conducted first. The results showed that the tensile and compression strength, stiffness, and tensile modulus of MCP decreased with increasing temperature. The Gibson model was found to be more suitable for predicting the high-temperature mechanical performance of MCP after comparing the calculated results of different theoretical models with experimental data. Secondly, high-temperature planar compression tests were conducted on the CGFRPP CSP, revealing that the main failure modes were corrugated core buckling and delamination between the face panel and core material, with delamination being intensified at higher temperatures. Therefore, we proposed a strength theoretical model that considers structural buckling failure and interface delamination failure, and introduced the influence factor to evaluate the effect of interface delamination on structural strength.

Analysis of composite honeycomb sandwich panels under blast loads

ABSTRACT This paper presents a novel isogeometric model to analyze the static bending, fre, and forced vibration characteristics of a sandwich of two-layer plates made of auxetic honeycomb core and laminated three-phase polymer/GNP/fiber skin subjected to a double blast load. The two layers are restricted from vertical movement by elastic pins but they can still move in the horizontal plane. The unique feature of the refined first-order shear plate theory with a distribution function g(z) is used to replace the shear correction factor, thereby allowing the shear stress at the top and bottom surfaces to be accurately calculated. The results are derived by the exact Navier solutions for rectangular plates and the IGA method with arbitrary boundary conditions for elliptical and rectangular plate structures. A comprehensive investigation was conducted to evaluate the influence of some parameters on the oscillation of sandwich two-layer plates subjected to double blast load.

Test methods for determination of shear properties of sandwich panels

This paper presents analysis and comparison of test methods for determining transverse shear strength and shear modulus of steel-faced sandwich panels commonly used in construction. The test methods are taken from the governing European standard EN 14509:2013. Two-point loading and four-point loading test methods as well as a full-scale test method are examined. Based on extensive experimental work on sandwich panels with varying core thickness, comprising mineral wool (MW) and polyisocyanurate (PIR) and encompassing both roof and wall panels, this study provides details of the test setup for the four-point loading and vacuum box methods with which a pure shear failure is obtained. Such details are missing from EN 14509. This paper highlights that the two-point loading method fails to consistently produce shear failure, especially in thicker panels, indicating it does not accurately measure transverse shear strength. The results of the experiments conducted in this study indicate that the four-point loading and full-scale test methods provide consistent shear failure for thicker panels while yielding greater transverse shear strength than the two-point loading test in general.