897 results on '"SANDWICH PANELS"'
Search Results
2. A semi-analytical model for predicting the shear buckling of laminated composite honeycomb cores in sandwich panels
- Author
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Sriharan, Jasotharan, Dias, Marcelo, Adhikari, Sondipon, and Fernando, Dilum
- Published
- 2025
- Full Text
- View/download PDF
Catalog
3. Flexural performance of UHPC sandwich panels with UHPC-filled stainless steel pipe shear connectors
- Author
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Ke, Lu, Wu, Xiulong, Yan, Banfu, Li, Wei, and Li, Youlin
- Published
- 2024
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- View/download PDF
4. Theoretical and experimental investigation of sandwich panels with 3D printed cores with GFRP composite and aluminum face sheets under 3-point bending.
- Author
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Chahardoli, S. and Akhavan Attar, Ali
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FUSED deposition modeling , *FIBROUS composites , *ALUMINUM sheets , *ALUMINUM composites , *COMPOSITE structures , *SANDWICH construction (Materials) - Abstract
Composite structures have been widely used in recent years in the aerospace industry as well as in industries that require lightweight structures due to their lightness and high strength-to-weight ratio. The purpose of this research is to introduce and compare a new type of sandwich panel to introduce structures that can be used in the aerospace industry. The cores in this research are made using Fused Deposition Modeling (FDM) with two types of PLA and ABS polymers. The face sheets used for this study are glass fiber reinforced composites and aluminum face sheets. In the first part of this study, a theoretical model for obtaining the force-displacement curve in nuclei with rectangular geometry was presented. Comparison of theoretical and experimental results showed that theoretical relationships have a good ability to predict the amount of force in experimental tests. The results obtained in this study showed that the use of composites made of epoxy glass fibers as a face sheet for sandwich panels leads to higher resistance to three-point bending. It was also found that sandwich panels made with ABS cores have higher strength compared to PLA cores, but their softness is less. [ABSTRACT FROM AUTHOR] more...
- Published
- 2025
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- View/download PDF
5. New method for predicting the wrinkling stress in sandwich panels.
- Author
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Su, Wenzheng and Liu, Shutian
- Abstract
It is necessary to accurately and efficiently calculate the wrinkling stresses of sandwich panels under in-plane compression. However, the simple equations used in engineering may obtain inaccurate results, whereas finite element methods with higher accuracy may be computationally expensive. This study proposes a new method for solving the wrinkling problem of sandwich panels using structural optimization theory at a low computational cost. A sandwich panel was divided into several virtual plies, which were assigned design variables to describe the vertical displacement during wrinkling. The wrinkling stress was obtained by minimizing the admissible in-plane compressive stress. The method was verified using finite element and experimental methods, as good agreement was found. The differences were less than 5% and 20% with the finite element and experimental results, respectively. Moreover, this method can easily compute the wrinkling stress of sandwich panels with functionally graded material cores with a little increase in computational cost. This method allows engineers to compute the wrinkling stress effectively and efficiently without the need for complex numerical models. [ABSTRACT FROM AUTHOR] more...
- Published
- 2025
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6. Impact of Infill Density and Glass Fiber Reinforcement on the Compressive and Bending Strength of Acrylonitrile Butadiene 3D‐Printed Corrugated Sandwich Panels.
- Author
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Sadooghi, Ali, Ebrahimian, Mohammad Reza, Hashemi, Seyed Jalal, Sayar, Rasool, Rahmani, Kaveh, and Bodaghi, Mahdi
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FUSED deposition modeling ,GLASS fibers ,SCANNING electron microscopes ,BENDING strength ,COMPRESSIVE strength ,SANDWICH construction (Materials) - Abstract
Sandwich panel structures are widely utilized across various industries due to their exceptional strength‐to‐weight ratios, particularly when employing a corrugated core. In this study, the innovative use of additive manufacturing and fused deposition modeling to produce corrugated core sandwich panels with enhanced mechanical properties are investigated. Acrylonitrile butadiene styrene filaments reinforced with varying percentages of glass fibers (0, 5, 10, and 15%) are utilized, and three distinct infill density patterns are examined. The panels are subjected to three‐point bending and compressive tests, revealing that a 10% glass fiber reinforcement yields the highest bending (1973.62 N) and compressive strengths (9581.56 N). Beyond this reinforcement level, strength decreases due to fiber agglomeration. Microstructural analysis using scanning electron microscope confirms optimal dispersion and bonding of glass fibers at 10%, which improves mechanical performance. Thermal analysis identified the appropriate printing temperatures, ensuring high‐quality layer adhesion. The novel approach of varying infill densities and fiber content contributes to optimizing 3D printing parameters, advancing the production of lightweight, high‐strength structures for applications in automotive, aerospace, and construction industries. In this study, significant insights into the relationship between material composition, manufacturing parameters, and mechanical properties of 3D‐printed sandwich panels are provided. [ABSTRACT FROM AUTHOR] more...
- Published
- 2025
- Full Text
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7. In-plane and out-of-plane compressive properties of regular and graded cellular cores of sandwich panels fabricated by additive manufacturing.
- Author
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Coelho, Bernardo, Copin, Etienne, Deus, Augusto Moita, and Fatima Vaz, Maria
- Abstract
Cellular materials with a gradient of properties become appealing as cores of the sandwich panels due to the possibility of improving strength and absorbed energy in lightweight components. 2D cellular structures designated by honeycombs have an anisotropic behaviour when loaded under in- and out-plane. Thus, when proposing new designs, it is essential to analyse how the in-plane arrangement with a gradient in cell wall thickness affects in-plane and out-of-plane mechanical properties. This work aims to study graded cellular structures in comparison with regular hexagonal honeycombs. Structures were manufactured by laser powder bed fusion using an aluminium alloy. Regular arrangements were formed with cells with the same thickness, while graded structures possessed a radial gradient of cell thickness. Three types of innovative gradients, where cell length varies radially along concentric layers, were analysed. The compressive properties of regular and graded structures were evaluated when loaded both under in-plane and out-of-plane conditions. Compression behaviour was assessed, both experimentally and by numerical modelling. Even though there is a mismatch between numerical and experimental results, they exhibit the same trends. All graded samples showed an increased mechanical performance when loaded under out-of-plane conditions in comparison with the results from tests under in-plane loading with values, for example, of stiffness four hundred times larger, absorbed energy around thirty times higher and with yield stress four times larger. The results showed that the graded samples attain higher values of strength, stiffness and absorbed energy in comparison with regular hexagonal honeycombs, for the same relative density. [ABSTRACT FROM AUTHOR] more...
- Published
- 2025
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8. Design and Multi-Objective Optimization of Auxetic Sandwich Panels for Blastworthy Structures Using Machine Learning Method.
- Author
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Andika, Santosa, Sigit Puji, Widagdo, Djarot, and Pratomo, Arief Nur
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SANDWICH construction (Materials) ,MULTI-objective optimization ,ALUMINUM foam ,ARMORED vehicles ,MACHINE learning - Abstract
The design and multi-objective optimization of auxetic sandwich panels (ASPs) are performed to enhance the blastworthiness of armored fighting vehicles (AFVs). Various metastructures in the form of four auxetic geometries are proposed as the sandwich core: re-entrant honeycomb (REH), double-arrow honeycomb (DAH), star honeycomb (SH), and tetra-chiral honeycomb (CH). This paper employs a combination of finite element and machine learning methodologies to evaluate blastworthiness performance. Optimization is carried out using the nondominated sorting genetic algorithm II (NSGA-II) method. The optimization results show significant improvements in blastworthiness performance, with notable reductions in permanent displacement and enhancements in specific energy absorption (SEA). Global sensitivity analysis using SHapley Additive exPlanations (SHAP) reveals that cell thickness is the most critical factor affecting blastworthiness performance, followed by the number of cells and corner angle or radius for CH. The application of optimized ASP on AFVs shows promising results, with no failure occurring in the occupant floor. Furthermore, AFVs equipped with the optimized ASP DAH significantly reduce maximum displacement and acceleration by 39.00% and 43.56%, respectively, and enhance SEA by 48.30% compared to optimized aluminum foam sandwich panels. This study concludes that ASPs have potential applications in broader engineering fields. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
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9. Study on the Dynamic Crushing Behaviors of Hourglass Honeycomb Sandwich Panels.
- Author
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Chen, Xinhai, Wang, Kai, Cao, Lu, Guo, Pengyu, Qin, Jiangyi, and Wu, Hexiang
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SANDWICH construction (Materials) ,HONEYCOMB structures ,AEROSPACE engineers ,AEROSPACE engineering ,COMPUTER simulation - Abstract
In response to the problem of enclosed internal spaces in existing honeycomb sandwich panels, the concept of an hourglass honeycomb sandwich panel model is proposed for the first time, which provides a breakthrough approach for achieving the multifunctional integration of honeycomb sandwich panels. Numerical simulation methods are employed to investigate the dynamic performance of the hourglass honeycomb sandwich panels. The focus is on discussing the influences of the geometric parameters on the deformation mode, dynamic response, load uniformity, and energy absorption capacity of the hourglass honeycomb sandwich panel under different impact velocity conditions. The research results indicate that under low-velocity-impact conditions, the influence of the geometric parameters is predominant. In contrast, under high-velocity-impact conditions, the influence of the impact velocity conditions is predominant. Hourglass honeycomb sandwich panels with low density, a large inclination angle of the honeycomb wall, and small contact distances between the hourglass honeycomb cell and the panel have excellent load uniformity, and the distances between the contact points of the hourglass honeycomb cell and the panel have a great influence on the energy absorption capacity of the sandwich panels. This study provides a theoretical basis for the application of honeycombs in aerospace and other engineering areas. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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10. Quantitative assessment of impact damage in stitched foam‐filled Aluminium honeycomb Sandwich panels by experimental and machine learning methods.
- Author
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Dhanesh, E., Nagarajan, V. A., Vinod Kumar, K. P., and Karthik, B.
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REGRESSION analysis , *MACHINE learning , *NYLON yarns , *HONEYCOMB structures , *IMAGE analysis , *SANDWICH construction (Materials) - Abstract
Novel Stitched Foam‐filled Honeycomb Sandwich (SFHS) panels have been fabricated using vacuum‐assisted resin transfer molding to address the weak interfaces between the face sheets and the core in the Foam‐filled Honeycomb Sandwich (FHS) panel. The SFHS panels have shown better load‐bearing capacity and performance characteristics compared to FHS panel after Low‐Velocity Impact (LVI) tests. After the LVI test, MATLAB image processing was used to analyze the impact damage areas and failure mechanisms. In addition, Machine Learning regression algorithms were employed to predict the optimal amount of energy absorbed during low‐velocity impact testing of fabricated panels with a maximum impactor drop height of 700 mm. The results indicated that nylon yarn stitching significantly improved energy absorption and interfacial behavior compared to unstitched honeycomb panels. This research also revealed that SFHS1 panels with adjacent honeycomb cell stitching are more impact resistant, provide increased load carrying capacity, and are cost‐effective. These panels can be utilized by modern engineers to increase economy, durability, and functionality in industrial, automotive, and construction applications. Highlights: Stitched Foam Filled Honeycomb Sandwich (SFHS) panels, manufactured via resin transfer molding, and eliminates weak interfaces between the face sheets and core.SFHS panels outperformed unstitched panels in load‐bearing and energy absorption during low‐velocity impact, as confirmed by MATLAB image analysis showing reduced damage and failure.Machine learning algorithms particularly polynomial regression model predicted maximum absorption energy precisely with 99.9% accuracy, close to experimental results.SFHS panels can be used in automotive and industrial applications due to their through‐thickness stitching. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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11. Experimental study on mechanical and thermal insulation properties of a geopolymer‐based fireproof sandwich panel.
- Author
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Pei, Rui, Hua, Luqing, Zhao, Hu, Wang, Xin, Li, Shiyang, and Wu, Zhishen
- Subjects
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THERMAL conductivity , *CORE materials , *THERMAL insulation , *THERMAL properties , *MINERAL wool , *SANDWICH construction (Materials) , *FIRE resistant polymers - Abstract
This work created a fireproof sandwich structure in which the face sheets were made of expanded vermiculite and expanded perlite‐filled geopolymer composites and embedded basalt fiber mats and the core material was rock wool in designing the lightweight and cost‐effective fire‐resistant structure for steel bridges with excellent retardant and heat‐insulating performance. The effects of adding 5%, 10%, 15%, and 20% expanded vermiculite and expanded perlite to the geopolymer on mechanical properties and the thermal conductivity were investigated to obtain the optimized material mixtures for preparing the face‐sheets material of the sandwich panel. Then, the fireproof sandwich structures were fabricated and exposed to 800°C for 3 h to study the structural integrity, backfire side temperature, and mass loss ratio. The results indicated that adding 10 wt% expanded vermiculite and 10 wt% expanded perlite to the geopolymer achieved the retention of compressive strength of 66.5% after being exposed to 800°C, and the geopolymer mixtures showed a low thermal conductivity of 0.1942 W/(mK). The TOPSIS evaluation analysis reveals that the proposed fireproof sandwich panel had the highest integrated performance considering the structural weight, insulation properties, and cost. The findings of this work may provide some insights into fireproof and insulating applications in bridge engineering. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
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12. Impact performance of egg‐box core sandwich panels made from sisal fibers and castor‐oil‐based polymer.
- Author
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Santos, Júlio C., Silva, Rodrigo J., Christoforo, André L., Freire, Rodrigo T. S., Tarpani, José Ricardo, Scarpa, Fabrizio, and Panzera, Túlio H.
- Subjects
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SANDWICH construction (Materials) , *NOTCHED bar testing , *SPECIFIC gravity , *POLYMER testing , *ALUMINUM construction , *SISAL (Fiber) - Abstract
Highlights Developing sustainable composites for engineering applications is essential for minimizing environmental impacts and ensuring the long‐term viability of infrastructure and technological advancements. In this context, this work focuses on the manufacture and evaluation of the structural integrity of a sandwich structure composed of aluminum faces and egg‐box‐shaped, sisal fiber‐reinforced epoxy (SFE) or castor‐oil polyurethane (SFC‐O) composites. The sandwich panel is filled with a biobased foam and subjected to dynamic load (drop‐tower) test. For comparison, the base materials SFE and SFC‐O molded into the egg‐box‐shaped cores are also evaluated using Charpy impact tests to establish a potential correlation between their Charpy performance and the drop‐tower behavior of egg‐box sandwich structures. The findings reveal that SFC‐O laminates demonstrate superior Charpy impact resistance (~49%) compared to SFE laminates. Similarly, sandwich structures composed of egg‐box‐castor‐oil composite cores absorb approximately 42.5% more energy than those made with egg‐box‐epoxy cores. The impact behavior of the sandwich structures correlates directly with the impact resistance of the sisal fiber laminates. Overall, the results indicate that the castor‐oil polymer can effectively replace the epoxy polymer matrix phase, enhancing impact absorption and providing an environmentally correct and sustainable solution for fabricating sandwich panels. Castor‐oil polymer provides laminates with lower density relative to epoxy. Sisal‐castor‐oil‐based laminates possess higher impact resistance than those based on epoxy. Sisal‐castor‐oil‐based panels achieve higher absolute and specific drop‐tower impact properties. Panels subjected to drop‐tower impact tests reveal skin delamination, wrinkling and indentation. Debonding between the foam and egg‐box core is a typical failure mode for epoxy sandwich panels. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
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13. A SIMPLIFIED DESIGN OF A CONCRETE SANDWICH STRUCTURE CONTAINING A REINFORCING RIB.
- Author
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MACHÁČEK, JAN, KAFKOVÁ, ELIŠKA, KABÍČKOVÁ, VĚRA, and VLACH, TOMÁŠ
- Subjects
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CONCRETE , *CARBON fiber-reinforced plastics , *COMPUTER software , *THERMAL insulation , *CARBON composites - Abstract
This article presents the use of a strut and tie analogy for modelling the behaviour of a concrete sandwich structure, which is formed by thin outer concrete layers made of high-performance concrete and reinforcing ribs. The beams transmitting shear are made of a rigid material with low thermal conductivity (Purenit) in combination with a carbon fibre reinforced polymer. The purpose of these ribs is to ensure reliable shear interaction of the outer concrete layers regardless of the thermal insulation of the sandwich structure. A simplified model using the truss analogy in the Scia Engineer software was used for the design of this structure. Furthermore, this design was verified experimentally on a section of the sandwich panel where the feasibility and functionality were tested by a four-point bending test. Finally, the theoretical values from the model were compared with the experimental results. This also includes a simple evaluation of whether this simplified modelling of the structure's behaviour is appropriate. The paper contains a summary of the conditions that could have affected the results. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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14. A comparative analysis between hexagonal and circular cells honeycombs based on integral 3D-printed sandwich panels.
- Author
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Campuzano, Alberto Jorge Baeza, da Silva, Rodrigo José, Silveira, Márcio Eduardo, Panzera, Túlio Hallak, and Scarpa, Fabrizio
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SANDWICH construction (Materials) , *CORE materials , *FLEXURAL modulus , *HONEYCOMB structures , *COMPARATIVE studies - Abstract
Honeycombs are commonly used as core materials in sandwich panels, and the core geometry significantly impacts the bending behaviour of these structures. Understanding how core characteristics influence the mechanical properties of sandwich panels is essential. The comparison between different honeycomb sandwich panel configurations is quite complex. This study delves into the intricate comparison between various honeycomb sandwich panel configurations, serving as a benchmark for integral 3D printed panels featuring hexagonal cores in both L- and W-directions, and circular cores. Notably, wrinkling phenomena are observed in the L-direction of the hexagonal cores. Circular cell panels exhibit increased load capacity, flexural modulus, and toughness. Additionally, hexagonal L-core panels demonstrate a higher toughness modulus than their W-core counterparts, making them less rigid yet stronger. Furthermore, L-cell core panels possess a lower density than circular cores, whereas W-cell cores exhibit higher density, compromising their specific mechanical properties. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
15. Vibration and acoustic properties of auxetic honeycomb sandwich panels with polyurea-metal laminate faceplates.
- Author
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Zhu, Jiamei, He, Qiang, Guo, Junlan, Zheng, Yin, Luo, Jin, and Wu, Sichen
- Subjects
- *
ACOUSTIC vibrations , *SANDWICH construction (Materials) , *TRANSMISSION of sound , *ACOUSTIC field , *SOUND pressure - Abstract
AbstractThe in-plane auxetic honeycomb sandwich panels (AHSPs) with polyurea-metal laminate (PML) as faceplates were proposed, and their vibration and acoustic properties were investigated. The natural frequency, damping loss factor, sound transmission loss (STL), and sound field pressure distribution were simulated by the finite element, which was then compared with the AHSP without a polyurea layer. The sound insulation properties of the AHSPs with PML faceplates were significantly enhanced due to the viscoelastic energy consumption of the polyurea layer. By changing the thickness of the polyurea layer and adopting different honeycomb geometries, the sound insulation ability of the sandwich plate could be further enhanced. The average STL rose by 2.3–4.7 dB when the polyurea layer thickness was increased, hence significantly improving the noise suppression ability of the AHSPs. When the geometric tilt angle θ of the honeycomb core is −45°, the sandwich panel exhibits superior sound insulation performance. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
16. Analytical and numerical analysis on local and global buckling of sandwich panels with strut-based lattice cores.
- Author
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Georges, Hussam, Becker, Wilfried, and Mittelstedt, Christian
- Subjects
- *
SANDWICH construction (Materials) , *COMPRESSION loads , *SHEAR (Mechanics) , *FINITE element method , *FAILURE mode & effects analysis , *MECHANICAL buckling - Abstract
Additive manufacturing (AM) offers new possibilities to fabricate and design lightweight lattice materials. Due to the superior mechanical properties of these lattice structures, they have the potential to replace honeycombs as cores in sandwich panels. In addition to the advantage of the integral fabrication thanks to AM, additively manufactured lattice core sandwich panels may be also used as heat exchangers, enabling a multifunctional use of the core. To ensure a reliable and safe structure, the mechanical response of lattice core sandwich panels under given load conditions must be predictable. In conventional sandwich panels subjected to compressive loads, the sandwich's global buckling and the face sheets' local buckling are the dominant failure modes. In constrast, core strut buckling may be the critical failure mode in lattice core sandwich panels. Therefore, an analytical 2D model to predict the local buckling of lattice core struts is considered in this study. Furthermore, the critical load for global buckling is obtained based on the first-order shear deformation theory. Thus, the transition from local buckling to global buckling depending on the length-to-thickness ratio is captured by the presented model. The comparison with finite element modeling of the sandwich model with truss cores has proved the accuracy of the derived model. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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17. Effect of Degradation of Polylactic Acid (PLA) on Dynamic Mechanical Response of 3D Printed Lattice Structures.
- Author
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Hedayati, Reza, Alavi, Melikasadat, and Sadighi, Mojtaba
- Subjects
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POISSON'S ratio , *YIELD stress , *SANDWICH construction (Materials) , *BRITTLENESS , *THREE-dimensional printing , *AUXETIC materials , *POLYLACTIC acid - Abstract
Material-extrusion-based 3D printing with polylactic acid (PLA) has transformed the production of lightweight lattice structures with a high strength-to-weight ratio for various industries. While PLA offers advantages such as eco-friendliness, affordability, and printability, its mechanical properties degrade due to environmental factors. This study investigated the impact resistance of PLA lattice structures subjected to material degradation under room temperature, humidity, and natural light exposure. Four lattice core types (auxetic, negative-to-positive (NTP) gradient in terms of Poisson's ratio, positive-to-negative (PTN) gradient in terms of Poisson's ratio, and honeycomb) were analyzed for variations in mechanical properties due to declines in yield stress and failure strain. Mechanical testing and numerical simulations at various yield stress and failure strain levels evaluated the degradation effect, using undegraded material as a reference. The results showed that structures with a negative Poisson's ratio exhibited superior resistance to local crushing despite material weakening. Reducing the material's brittleness (failure strain) had a greater impact on impact response compared to reducing its yield stress. This study also revealed the potential of gradient cores, which exhibited a balance between strength (maintaining similar peak force to auxetic cores around 800 N) and energy absorption (up to 40% higher than auxetic cores) under moderate degradation (yield strength and failure strain at 60% and 80% of reference values). These findings suggest that gradient structures with varying Poisson's ratios employing auxetic designs are valuable choices for AM parts requiring both strength and resilience in variable environmental conditions. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
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18. High-force Mechanical Dynamic Investigation of Natural Fiber Composite Sandwich Panels for Aerospace Design.
- Author
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Alqahtani, Bader
- Subjects
NATURAL fibers ,CORE materials ,DEAD loads (Mechanics) ,FIBROUS composites ,TRANSITION temperature - Abstract
In this paper, the non-destructive assessment of thermo-mechanical characteristics of extremely rigid structures made up of natural composites fibers is conducted. Higher-force dynamic mechanical investigation has allowed for new insights, which is not possible with the regularly employed static and impact test methods. Natural fibers made up of composite sandwich panels with aluminum and aramid honeycomb cores are studied. Various panel cores of equal stiffness and damping capabilities are compared over flight frequencies ranging from 1 to 100 Hz. It was discovered that the exhaustion of the natural fiber sandwich panels depends on both the core material and the applied static load. Additionally, temperature sweeps were carried out, and it was discovered that they can identify variations in the post processing of the natural fiber laminated panels and show the variations in the transition temperature of the matrix material. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
19. Developing a lightweight corrugated sandwich panel based on tea oil camellia shell: correlation of experimental and numerical performance
- Author
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Kamran Choupani Chaydarreh, Jingyi Tan, Yonghui Zhou, Yongtao Li, and Chuanshuang Hu
- Subjects
Sandwich panels ,Tea oil camellia shell ,Corrugated structure ,Particleboard ,Fiberboard ,Forestry ,SD1-669.5 ,Building construction ,TH1-9745 - Abstract
Abstract This study presents an experimental and numerical comparison between the mechanical performance of a lightweight corrugated sandwich panel based on the tea oil camellia shell (TOCS). Hence, TOCS was mixed in two groups with Poplar particles and fibers. After that, in the experimental part, the conventional mechanical tests, including the 3-point bending test, flatwise compression, dowel bearing, and screw resistance, and in the numerical part, finite element analysis (FEA), including the normal, maximum principal, and equivalent (von Mises) stress by Ansys Mechanical software carried out. The specimens for experimental and numerical tests were prepared in transverse and longitudinal directions. Before that, the engineering data (shear modulus, Young's modulus, and Poisson's ratio) for improving the FEA simulation were obtained from TOCS-based flat panels fabricated with a mixture of Poplar particles and fibers. The results of FEA are used to compare the mechanical behavior and failure mechanism with the results of experimental tests. According to the mean values of bending stiffness and maximum bending moment, sandwich panels made with 100% particles demonstrated an advantage in both directions. Nevertheless, the compression strength and screw resistance showed the same trend, but the dowel bearing showed higher values for panels made with fibers. The observed results of equivalent (von Mises) stress indicated a coloration with the results of failure mechanisms. more...
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- 2024
- Full Text
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20. Sound Absorption Performance of Ultralight Honeycomb Sandwich Panels Filled with "Network" Fibers— Juncus effusus.
- Author
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Liu, Zhao, Dong, Chenhao, Tong, Lu, Rudd, Chris, Yi, Xiaosu, and Liu, Xiaoling
- Subjects
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ABSORPTION of sound , *ARTIFICIAL neural networks , *HONEYCOMB structures , *NATURAL fibers , *FIBERS , *NOISE control , *SANDWICH construction (Materials) - Abstract
This study investigates lightweight and efficient candidates for sound absorption to address the growing demand for sustainable and eco-friendly materials in noise attenuation. Juncus effusus (JE) is a natural fiber known for its unique three-dimensional network, providing a viable and sustainable filler for enhanced sound absorption in honeycomb panels. Microperforated-panel (MPP) honeycomb absorbers incorporating JE fillers were fabricated and designed, focusing on optimizing the absorber designs by varying JE filler densities, geometrical arrangements, and MPP parameters. At optimal filling densities, the MPP-type honeycomb structures filled with JE fibers achieved high noise reduction coefficients (NRC) of 0.5 and 0.7 at 20 mm and 50 mm thicknesses, respectively. Using an analytical model and an artificial neural network (ANN) model, the sound absorption characteristics of these absorbers were successfully predicted. This study demonstrates the potential of JE fibers in improving noise mitigation strategies across different industries, offering more sustainable and efficient solutions for construction and transportation. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
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21. Mechanical analysis of al/foam composite sandwich panels under elastic and elastoplastic states.
- Author
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Eruslu, Sait Özmen
- Subjects
MATERIALS science ,TIMOSHENKO beam theory ,EULER-Bernoulli beam theory ,LAMINATED composite beams ,STRAINS & stresses (Mechanics) ,SANDWICH construction (Materials) ,COMPOSITE plates - Published
- 2024
- Full Text
- View/download PDF
22. Developing a lightweight corrugated sandwich panel based on tea oil camellia shell: correlation of experimental and numerical performance.
- Author
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Choupani Chaydarreh, Kamran, Tan, Jingyi, Zhou, Yonghui, Li, Yongtao, and Hu, Chuanshuang
- Abstract
This study presents an experimental and numerical comparison between the mechanical performance of a lightweight corrugated sandwich panel based on the tea oil camellia shell (TOCS). Hence, TOCS was mixed in two groups with Poplar particles and fibers. After that, in the experimental part, the conventional mechanical tests, including the 3-point bending test, flatwise compression, dowel bearing, and screw resistance, and in the numerical part, finite element analysis (FEA), including the normal, maximum principal, and equivalent (von Mises) stress by Ansys Mechanical software carried out. The specimens for experimental and numerical tests were prepared in transverse and longitudinal directions. Before that, the engineering data (shear modulus, Young's modulus, and Poisson's ratio) for improving the FEA simulation were obtained from TOCS-based flat panels fabricated with a mixture of Poplar particles and fibers. The results of FEA are used to compare the mechanical behavior and failure mechanism with the results of experimental tests. According to the mean values of bending stiffness and maximum bending moment, sandwich panels made with 100% particles demonstrated an advantage in both directions. Nevertheless, the compression strength and screw resistance showed the same trend, but the dowel bearing showed higher values for panels made with fibers. The observed results of equivalent (von Mises) stress indicated a coloration with the results of failure mechanisms. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
23. Prediction of screw withdrawal resistance for plywood laminated panels and sandwich panels
- Author
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Ergün Güntekin and Mesut Uysal
- Subjects
screw withdrawal resistance ,screw withdrawal strength ,sandwich panels ,plywood ,medium-density fiberboard ,particleboard ,vida çekme kapasitesi ,vida çekme dayanımı ,sandviç paneller ,kontrplak ,mdf ,yonga levha ,Forestry ,SD1-669.5 - Abstract
Sandwich panels are favorable materials for structural or non-structural components due to durability, lightness, and longevity in service life. This study aimed to predict screw withdrawal resistance of the plywood laminated medium-density fiberboard and particleboard, and sandwich panels. In predicting the screw withdrawal resistance, withdrawal load capacity, density, and withdrawal stiffness of the materials in each layer, screw penetration depth, and screw diameter were considered. Moreover, the screw withdrawal strength of the panels was examined. Screw withdrawal tests of panels were conducted according to TS EN 13446 standard. The test results showed a proportional correlation between the density and screw withdrawal strength of the panels. The highest screw withdrawal strength was obtained for sandwich panels made of plywood and medium-density fiberboard (12.51 MPa). Furthermore, the difference between experimental and predicted screw withdrawal resistance changed from 0.20% to 24.86%. Besides, there was no statistically significant difference between the screw withdrawal strength of the top and bottom face-laminated panels. The test results showed that both face laminated panels (sandwich panels) had higher screw withdrawal strength, density, and experimental and predicted screw withdrawal resistance compared to one face laminated panels. more...
- Published
- 2024
- Full Text
- View/download PDF
24. Low-velocity impact response of hybrid core sandwich panels with spring and strut cores filled with resin, silicone, and foam
- Author
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Charkaoui, Assil, Hassan, Noha M., Bahroun, Zied, and Ibrahim, Mahmoud
- Published
- 2024
- Full Text
- View/download PDF
25. Efficient design of sandwich panels with cellular truss cores and large phononic band gaps using surrogate modeling and global optimization.
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Meruane, Viviana, Puiggros, Ignacio, Fernandez, Ruben, and Ruiz, Rafael O.
- Subjects
BAND gaps ,SANDWICH construction (Materials) ,GLOBAL optimization ,MACHINE learning ,ARTIFICIAL neural networks - Abstract
Recent advancements in additive manufacturing technologies and topology optimization techniques have catalyzed a transformative shift in the design of architected materials, enabling increasingly complex and customized configurations. This study delves into the realm of engineered cellular materials, spotlighting their capacity to modulate the propagation of mechanical waves through the strategic creation of phononic band gaps. Focusing on the design of sandwich panels with cellular truss cores, we aim to harness these band gaps to achieve pronounced wave suppression within specific frequency ranges. Our methodology combines surrogate modeling with a comprehensive global optimization strategy, employing three machine learning algorithms--k-Nearest Neighbors (kNN), Random Forest Regression (RFR), and Artificial Neural Networks (ANN)--to construct predictive models from parameterized finite element (FE) analyses. These models, once trained, are integrated with Particle Swarm Optimization (PSO) to refine the panel designs. This approach not only facilitates the discovery of optimal truss core configurations for targeted phononic band gaps but also showcases a marked increase in computational efficiency over traditional optimization methods, particularly in the context of designing for diverse target frequencies. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
26. Low-Velocity Impact Damage Quantification on Sandwich Panels by Thermographic and Ultrasonic Procedures.
- Author
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Pirinu, A., Saponaro, A., Nobile, R., and Panella, F. W.
- Subjects
- *
SANDWICH construction (Materials) , *IMPACT (Mechanics) , *ULTRASONIC arrays , *PHASED array antennas , *ULTRASONICS , *NONDESTRUCTIVE testing , *ULTRASONIC testing - Abstract
Composite sandwich structures are widely used for their mechanical properties combined to lightweight. However, damage area quantification caused by low velocity impacts represents generally a crucial task in sandwich composites. In the last years, recent advantages of thermographic devices offer new promising and different real-time industrial and engineering applications where lower computation time, accuracy of results and convenient cost are required. The present research deals with the comparison of standard or latest image-processing methods proposed for pulsed thermography regarding their suitability for determining the impact damage area in sandwich materials made of Aluminium core an a GFRP laminated skins. The Infra-Red processed results are compared with the advanced ultrasonic Phased array method commonly employed in the industrial Non-Destructive Testing. Specifically, the damage area quantification is performed by means of an appropriate MATLAB binarization algorithm for the post-processing of acquired thermal and ultrasonic maps. The data results verify the effectiveness of the image-processing thermographic technique combined to advanced processing approaches for the quantitative assessment of impact damage in sandwich component. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
27. Thermo-Environmental Performance of Modular Building Envelope Panel Technologies: A Focused Review.
- Author
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Mohammed, Mohammed Alhaji, Budaiwi, Ismail M., Al-Osta, Mohammed A., and Abdou, Adel A.
- Subjects
BUILDING envelopes ,BUILDING performance ,MODULAR construction ,BUILDING-integrated photovoltaic systems ,WALL panels ,CLIMATE change ,TEMPERATE climate - Abstract
Modular construction is becoming famous for buildings because it allows a high degree of prefabrication, with individual modules easily transported and installed. Building envelope optimization is vital as it protects buildings from undesirable external environments by expressly preventing the incursion of outside elements. This research uses a systematic literature review to appraise the characteristics of modular envelope panels, focusing on hygrothermal and energy performance. A total of 265 articles were subjected to rigorous filtering and screening measures. The findings reveal notable inconsistencies in modular envelope terminologies and a lack of consistent performance measures, which present significant challenges for research and development efforts. Furthermore, the results indicate a predominant focus on hygrothermal and energy performance in existing studies, with limited attention to environmental impacts and other performance factors. Moreover, the existing literature primarily addresses modular envelope solutions in temperate climates, offering inadequate information for hot and hot–humid climate contexts. To address these gaps, this study proposes categorizing modular envelope panels into four distinct categories: active, passive, smart, and green/vegetated wall panels. These findings will benefit researchers, architects, building envelope designers, policymakers, and organizations developing building performance-related assessment ratings, standards, and codes. The study suggests adopting the categorization of modular envelope panels provided in this study and developing modular panels suitable for hot and humid climates to fill the existing knowledge gap. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
28. An analytical closed-form solution for free vibration and stability analysis of curved sandwich panels made of porous metal-foam core and nanocomposite reinforced face-sheets.
- Author
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Badarloo, Baitollah and Salehipour, Hamzeh
- Abstract
This paper aims to obtain an analytical solution for free vibration and stability analysis of shallow curved sandwich panels made of a porous metal-foam core and nanocomposites reinforced sheets resting on a Winkler-Pasternak elastic foundation. In this regard, two nanocomposites, carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) are considered for reinforcing the face-sheets. The governing equations are developed by considering the transversal shear strains based on the first-order shear deformation theory (FSDT). The obtained system of differential equations representing the dynamic equilibrium and compatibility of the proposed curved sandwich panels are solved analytically, using the principal of Galerkin method. In order to examine the results of developed formulation, some benchmark examples are adopted from the existing literature and the obtained results corresponding to the considered examples are compared with those are presented in the references. Using the achieved numerical results in the framework of a comprehensive parametric study, the effects of various material and geometrical factors and also various boundary conditions on the natural frequencies and buckling loads of the proposed sandwich panels are assessed. By performing the extensive parametric study it was observed that several results corresponding to the free vibration and stability of the proposed sandwich panels can be achieved by the present method without spending much time for computations. On the contrary, in order to achieve the similar results using the numerical methods, a time-consuming process is required which can justify the novelty of the present work. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
29. Mechanical Performance Comparison of Sandwich Panels with Graded Lattice and Honeycomb Cores.
- Author
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Georges, Hussam, García Solera, Diego, Aguilar Borasteros, Carlos, Metar, Mohmad, Song, Gyeongseob, Mandava, Rahul, Becker, Wilfried, and Mittelstedt, Christian
- Subjects
- *
HONEYCOMBS , *SANDWICH construction (Materials) , *HONEYCOMB structures - Abstract
The design of graded and multifunctional lattice cores is driven by the increasing demand for high-performance components in lightweight engineering. This trend benefits from significant achievements in additive manufacturing, where the lattice core and the face sheets are fabricated simultaneously in a single print job. This work systematically compares the mechanical performance of sandwich panels comprising various graded lattice cores subjected to concentrated loads. In addition to graded lattice cores, uniform lattices and conventional honeycomb cores are analyzed. To obtain an optimized graded lattice core, a fully stressed design method is applied. Stresses and displacements are determined using a linear elastic analytical model that allows grading the core properties in a layerwise manner through the core thickness. The analysis indicates the superior performance of graded lattice cores compared to homogeneous lattice cores. However, conventional honeycombs outperform graded lattice cores in terms of load-to-weight ratio and stiffness-to-weight ratio. This study provides valuable insights for the design of lattice core sandwich panels and the advantages of several design approaches. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
30. Dynamic stability of sandwich panels subjected to periodic axial loads.
- Author
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Yuan, Zhangxian and Kardomateas, George A
- Subjects
- *
SANDWICH construction (Materials) , *AXIAL loads , *HAMILTON'S principle function , *EQUATIONS of motion , *FLOQUET theory , *BLAST effect , *DYNAMIC loads , *DYNAMIC stability - Abstract
This paper presents an analysis for the dynamic stability of sandwich beams/wide plates subjected to periodic axial loads. The formulation of the problem is done by use of the Extended High-order Sandwich Panel Theory (EHSAPT). The equations of motion are derived from Hamilton's principle and are expressed in terms of seven generalized displacements. A sandwich panel with simply supported edges is studied as an example, and the equations of motion for a given harmonic n are further derived. Two time-variations for the axial forces, namely, harmonic axial forces and step-wise periodic axial forces, are considered in this work. By considering the features of these two periodic load profiles, Floquet theory and Bolotin's method are adopted to perform the dynamic stability analysis. Sandwich panels with different face-to-core thickness ratios are studied. Stability maps for varying frequency and amplitude of the forces are presented. Numerical examples show that when a sandwich panel is subjected to periodic loads, it is possible that it can experience dynamic instability even when the dynamic loads are much lower than the static critical loads. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
31. Investigating the energy absorption properties of sandwich panels filled with shear thickening fluid with a weight fraction of 35% under low-velocity impact.
- Author
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Astaraki, Sajjad, Zamani, Ehsan, Pol, Mohammad Hossein, and Hasan-nezhad, Hosein
- Subjects
- *
SANDWICH construction (Materials) , *ALUMINUM sheets , *GLASS composites , *IMPACT testing , *ABSORPTION - Abstract
This research study the energy absorption performance of aluminum core honeycomb sandwich panel (ACHSP) with filled and empty cores subjected to low-velocity impact testing, with diverse skins; (i) aluminum sheets, (ii) 5-ply epoxy glass composite, and (iii) 5-ply shear thickening fluid (STF)-impregnated glass fabrics. The prepared STF was 35 wt% and the impactor heights was selected at 100 and 500 mm to assess the effect of different impact velocities on the energy absorption capability of STF. The specific energy absorption (SEA) of the STF-filled ACHSP with 5-ply STF-impregnated fabrics skin (height of 500 mm) compared to STF-filled ACHSP with aluminum sheets skin and 5-ply epoxy glass composite skin have increased by 28.38 and 21.79%, respectively. In a fact of truth, when the external force is applied to the STF-filled ACHSP, the fluid transitions from a low-velocity to a high-velocity state instantly. This transition exerts forces on the suspended particles within the fluid. Actually, during the impact, the particles come into close contact and form temporary particle networks or chains. These networks increase the viscosity of the fluid, making it resistant to flow. The energy of the impact is then absorbed by the formation and reformation of these particles' networks. However, the SEA of STF-filled ACHSP at the height of 500 mm to empty ACHSP at the height of 100 mm have decreased significantly, and the energy absorption of STF-filled ACHSPs to corresponding empty ACHSPs have increased remarkably. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
32. Study on the Dynamic Crushing Behaviors of Hourglass Honeycomb Sandwich Panels
- Author
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Xinhai Chen, Kai Wang, Lu Cao, Pengyu Guo, Jiangyi Qin, and Hexiang Wu
- Subjects
hourglass honeycombs ,sandwich panels ,dynamic performance ,load uniformity ,energy absorption ,Motor vehicles. Aeronautics. Astronautics ,TL1-4050 - Abstract
In response to the problem of enclosed internal spaces in existing honeycomb sandwich panels, the concept of an hourglass honeycomb sandwich panel model is proposed for the first time, which provides a breakthrough approach for achieving the multifunctional integration of honeycomb sandwich panels. Numerical simulation methods are employed to investigate the dynamic performance of the hourglass honeycomb sandwich panels. The focus is on discussing the influences of the geometric parameters on the deformation mode, dynamic response, load uniformity, and energy absorption capacity of the hourglass honeycomb sandwich panel under different impact velocity conditions. The research results indicate that under low-velocity-impact conditions, the influence of the geometric parameters is predominant. In contrast, under high-velocity-impact conditions, the influence of the impact velocity conditions is predominant. Hourglass honeycomb sandwich panels with low density, a large inclination angle of the honeycomb wall, and small contact distances between the hourglass honeycomb cell and the panel have excellent load uniformity, and the distances between the contact points of the hourglass honeycomb cell and the panel have a great influence on the energy absorption capacity of the sandwich panels. This study provides a theoretical basis for the application of honeycombs in aerospace and other engineering areas. more...
- Published
- 2024
- Full Text
- View/download PDF
33. Efficient design of sandwich panels with cellular truss cores and large phononic band gaps using surrogate modeling and global optimization
- Author
-
Viviana Meruane, Ignacio Puiggros, Ruben Fernandez, and Rafael O. Ruiz
- Subjects
phononic metamaterials ,sandwich panels ,band gaps ,machine learning ,surrogate optimization ,Mechanical engineering and machinery ,TJ1-1570 - Abstract
Recent advancements in additive manufacturing technologies and topology optimization techniques have catalyzed a transformative shift in the design of architected materials, enabling increasingly complex and customized configurations. This study delves into the realm of engineered cellular materials, spotlighting their capacity to modulate the propagation of mechanical waves through the strategic creation of phononic band gaps. Focusing on the design of sandwich panels with cellular truss cores, we aim to harness these band gaps to achieve pronounced wave suppression within specific frequency ranges. Our methodology combines surrogate modeling with a comprehensive global optimization strategy, employing three machine learning algorithms—k-Nearest Neighbors (kNN), Random Forest Regression (RFR), and Artificial Neural Networks (ANN)—to construct predictive models from parameterized finite element (FE) analyses. These models, once trained, are integrated with Particle Swarm Optimization (PSO) to refine the panel designs. This approach not only facilitates the discovery of optimal truss core configurations for targeted phononic band gaps but also showcases a marked increase in computational efficiency over traditional optimization methods, particularly in the context of designing for diverse target frequencies. more...
- Published
- 2024
- Full Text
- View/download PDF
34. Life cycle assessment of fibre metal laminates: An ecodesign approach
- Author
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Guilherme Germano Braga, Gabriela Giusti, Júlio César dos Santos, Diogo Aparecido Lopes Silva, André Luis Christoforo, Túlio Hallak Panzera, and Fabrizio Scarpa
- Subjects
Sandwich panels ,Castor-oil polymer ,Natural fibres ,Eco-efficiency ,Circular economy ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Despite the extensive research on renewable resources (RR) and their potential applications in composite materials and sandwich structures, there remains a significant dearth of life cycle assessment (LCA) studies that comprehensively evaluate the efficacy of RR in mitigating environmental impacts (EI). To bridge this gap, the present study aims to investigate twelve different designs of sandwich panels, specifically referred to as Fibre Metal Laminates (FML). These FML combine aluminium skins (2024-T3 and 1200-H14), polymer matrices (Epoxy, Polyester, and Castor oil Bio-PU), natural fibres (Sisal, Coir, and Cynodon spp.), surface treatments for aluminium skins (sanding, NaOH, and Washprimer), and treatments for natural fibres (Ground, NaOH-treatment and untreated). A cradle-to-gate LCA is conducted, and the inventories are modelled using the OpenLCA 1.6.3 and ecoinvent 3.9 cut-off regionalized database. EI are evaluated in twelve categories, including climate change, fossil and nuclear energy use, freshwater (acidification, ecotoxicity and eutrophication), human toxicity (cancer and non-cancer), mineral resources use, ozone layer depletion, particulate matter formation, photochemical oxidant formation, and terrestrial acidification. Impact World+ method for Latin America version 1.251 is employed to calculate EI. Nine Eco-efficiency indicators and trade-off analyses are evaluated to gain insights into design decision outcomes. Among the various panels considered, FML12, manufactured with aluminium alloy 1200-H14 treated only with sanding, castor oil biopolymer and untreated coir fibres, present the most consistent eco-efficiency indicators. The reference scenario considers the average characteristics of FML (both environmental and mechanical) for trade-off analysis. Despite the fifty percent chance of better performance, FML12 is the only panel that shows higher mechanical performance and lower EI compared to the reference scenario. The importance of this article lies in the novel results obtained using the proposed eco-efficiency indicators, which can be expanded in further studies on the topic. more...
- Published
- 2024
- Full Text
- View/download PDF
35. Functionally graded multi-morphology lattice structures as an optimized sandwich core via digital light processing additive manufacturing
- Author
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M. Mahmoudi, S.A.M. Ghannadpour, and K. Hossein Nedjad
- Subjects
Sandwich panels ,3D Printing ,Multi morphology ,Functionally graded lattice structures ,Three-point bending ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
This investigation aims to present a high-strength sandwich core with functionally graded multi-morphology lattice inner structures through vat photo-polymerization additive manufacturing (AM). The five better strut-based designs based on [1], are considered here. All printed specimens have been fabricated from photopolymer resin to ensure manufacturability in a digital light processing (DLP) 3D printer. Firstly, the resin and structural characteristics have been examined. Simultaneously, the lattice core is divided into three regions based on the von Mises stress distribution and tensile and compression responses in finite element analysis (FEA). Based on the mechanical responses of the beam-based structures, these topologies have been applied in each region in an optimal fixed relative density distribution, considering different steps and types. This proposed technique is numerically investigated and experimentally validated using a three-point bending test. As a result, the optimized core demonstrated a 96% increase in maximum fracture force and a 174% increase in stiffness compared to the homogeneous body. Additionally, it exhibited a different deformation mode than the single morphology under similar conditions. These significant findings indicate that this approach provides a new perspective on a high-strength design involving more than three morphologies, and it is faster than computational topology optimization processes. more...
- Published
- 2024
- Full Text
- View/download PDF
36. Warping Torsion in Sandwich Panels: Analyzing the Structural Behavior through Experimental and Numerical Studies.
- Author
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Pradhan, Eric Man and Lange, Jörg
- Subjects
- *
SANDWICH construction (Materials) , *STRUCTURAL panels , *TORSION , *BENDING stresses , *CURTAIN walls , *SHEARING force , *BUILDING envelopes - Abstract
Recently, there has been a growing interest in the use of sandwich panels that, beyond handling well-known bending stress, can withstand torsional stresses. This is particularly relevant for wall applications when the panels are equipped with photovoltaic or supplemental curtain wall modules. This research article presents a detailed exploration of the structural behavior of eccentrically loaded sandwich panels, with a specific focus on warping torsion. Experimental and numerical studies were conducted on polyisocyanurate (PU) core sandwich panels, commonly employed in building envelopes. These studies involved various dimensions and material properties, while omitting longitudinal joints. The experimental study provided essential insights and validated the numerical model in ANSYS. Enabling parametric variation, the numerical analysis extends the analysis beyond the experimental scope. Results revealed a high degree of correlation between experimental, numerical, and analytical solutions, regarding the rotation, as well as the normal and shear stress of the panel. Confirming the general applicability of warping torsion in sandwich panels with certain limitations, the study contributes valuable data for applications and design of eccentrically loaded sandwich panels, laying the foundation for potential engineering calculation methods. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
37. Material Behavior of PIR Rigid Foam in Sandwich Panels: Studies beyond Construction Industry Standard.
- Author
-
Steineck, Sonja and Lange, Jörg
- Subjects
- *
SANDWICH construction (Materials) , *CONSTRUCTION industry standards , *CORE materials , *FOAM , *STRESS-strain curves , *ROOFING industry - Abstract
A deep understanding of the material parameters and the behavior of sandwich panels, which are used in the construction industry as roof and façade cladding, is important for the design of these construction components. Due to the constant changes in the polyurethane (PU) foams used as a core material, the experimental database for the current foams is small. Nowadays, there is an increasing number of failures of façade and roof panels after installation. This article presents a variety of experimental investigations on sandwich panels from two manufacturers with a core of polyisocyanurate (PIR) rigid foam (density: 40 kg/m3). As part of this study, compression, tension, shear, and bending tests were performed in several spatial directions and over the range required by the standard. The results of the tests showed the orthotropy of the core material and the dependence of the material on the direction and type of load. The stress-strain curves showed linear and non-linear areas. Using the data from this experimental study, a numerical model was implemented which utilized the Hill yield criterion to represent the orthotropy of the core material. The present investigation suggests that the classical von Mises failure criterion, used in many studies, is not suitable for the foam system applied in these sandwich panels. Instead, the Tsai–Wu criterion is more appropriate for defining the failure stresses. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
38. Shear Performance of the Interface of Sandwich Specimens with Fabric-Reinforced Cementitious Matrix Vegetal Fabric Skins.
- Author
-
Gil, Lluís, Mercedes, Luis, Mendizabal, Virginia, and Bernat-Maso, Ernest
- Subjects
SISAL (Fiber) ,MORTAR ,SYNTHETIC textiles ,SANDWICH construction (Materials) ,SYNTHETIC fibers ,COMPOSITE materials - Abstract
Featured Application: The design and manufacturing of sandwich solutions using FRCM vegetal fabric skins improve sustainability because they provide solutions with a lower global carbon footprint. The utilization of the vegetal fabric-reinforced cementitious matrix (FRCM) represents an innovative approach to composite materials, offering distinct sustainable advantages when compared to traditional steel-reinforced concrete and conventional FRCM composites employing synthetic fibers. This article introduces a design for sandwich solutions based on a core of extruded polystyrene and composite skins combining mortar as a matrix and diverse vegetal fabrics as fabrics such as hemp and sisal. The structural behavior of the resulting sandwich panel is predominantly driven by the interaction between materials (mortar and polyurethane) and the influence of shear connectors penetrating the insulation layer. This study encompasses an experimental campaign involving double-shear tests, accompanied by heuristic bond-slip models for the potential design of sandwich solutions. The analysis extends to the examination of various connector types, including hemp, sisal, and steel, and their impact on the shear performance of the sandwich specimens. The results obtained emphasize the competitiveness of vegetal fabrics in achieving an effective composite strength comparable to other synthetic fabrics like glass fiber. Nevertheless, this study reveals that the stiffness of steel connectors outperforms vegetal connectors, contributing to an enhanced improvement in both stiffness and shear strength of the sandwich solutions. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
39. Wooden sandwich panels with auxetic core for furniture - experimental and numerical analysis.
- Author
-
Zhong, Yanan, Ren, Yi, Zhang, Jijuan, and Zhang, Zhongfeng
- Subjects
- *
SANDWICH construction (Materials) , *POISSON'S ratio , *NUMERICAL analysis , *MODULUS of elasticity , *CABINETS (Furniture) , *WOOD - Abstract
Honeycomb panels manufactured from wood and paper materials promote a high-value utilization of wood resources. However, the poor mechanical properties and uncommon thicknesses (32 and 40 mm) of paper honeycomb panels limit their application and promotion in the panel furniture industry. Hence, numerous attempts have been made to develop high-strength and low-density wood sandwich composites for the frames and partitions of cabinet furniture. This paper describes a method for manufacturing lightweight sandwich panels (18 mm thickness) with auxetic cores, made of fast-growing poplar. The mechanical properties of the panels and the negative Poisson's ratio of the perforated sheet cores were determined by three-point bending and uniaxial compression tests. The lower density, higher modulus of elasticity, and bending strength suggest that the developed panel is a good substitute for traditional wood-based panels. A numerical model for panels in bending tests is proposed and validated against the experimental analysis results. These investigations facilitate further research into optimizing the sandwich panel structure and its applicability in the architectural and furniture industry. Graphical Abstract [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
40. PLA-Based Composite Panels Prepared via Multi-Material Fused Filament Fabrication and Associated Investigation of Process Parameters on Flexural Properties of the Fabricated Composite.
- Author
-
Wang, Zhaogui, Wang, Lihan, Tang, Feng, and Shen, Chengyang
- Subjects
- *
POLYLACTIC acid , *FLEXURAL modulus , *TAGUCHI methods , *BENDING strength , *FIBERS , *FLEXURAL strength - Abstract
This study prepares composite panels with three Polylactic acid (PLA)-based materials via the multi-material fused filament fabrication method. The influences of four processing parameters on the mechanical properties of 3D-printed samples are investigated employing the Taguchi method. These parameters include the relative volume ratio, material printing order, filling pattern, and filling density. A "larger is better" signal-to-noise analysis is performed to identify the optimal combination of printing parameters that yield maximum bending strength and bending modulus of elasticity. The results reveal that the optimal combination of printing parameters that maximizes the bending strength involves a volume ratio of 1:1:2, a material sequence of PLA/foam-agent-modified eco-friendly PLA (ePLA-LW)/glass fiber-reinforced eco-friendly PLA (ePLA-GF), a Gyroid filling pattern, and a filling density of 80%, and the optimal combination of printing parameters for maximum bending modulus involves a volume ratio of 1:2:1 with a material sequence of PLA/ePLA-LW/ePLA-GF, a Grid filling pattern, and 80% filling density. The Taguchi prediction method is utilized to determine an optimal combination of processing parameters for achieving optimal flexural performances, and predicted outcomes are validated through related experiments. The experimental values of strength and modulus are 43.91 MPa and 1.23 GPa, respectively, both very close to the predicted values of 46.87 MPa and 1.2 GPa for strength and modulus. The Taguchi experiments indicate that the material sequence is the most crucial factor influencing the flexural strength of the composite panels. The experiment result demonstrates that the flexural strength and modulus of the first material sequence are 67.72 MPa and 1.53 GPa, while the flexural strength and modulus of the third material sequence are reduced to 27.09 MPa and 0.72 GPa, respectively, only 42% and 47% of the first material sequence. The above findings provide an important reference for improving the performance of multi-material 3D-printed products. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
41. Instrumented Dynamic Penetration of Sandwich Panels with Auxetic and Non‐Auxetic Core using Direct Impact Hopkinson Bar.
- Author
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Šleichrt, Jan, Falta, Jan, Neuhäuserová, Michaela, Drechslerová, Veronika, Koudelka, Petr, Rada, Václav, Fíla, Tomáš, and Jiroušek, Ondřej
- Subjects
SANDWICH construction (Materials) ,PENETRATION mechanics ,DIGITAL image correlation ,UNIT cell ,SPECIFIC gravity - Abstract
This article deals with the dynamic penetration of 3D‐printed panels with auxetic and conventional honeycomb unit cell‐based cores. The geometry of the unit cells and their periodic assembly in the resulting lattices are selected to ensure the same relative density and overall weight of the individual sample types. Such a similarity of both specimen types allows for the evaluation of differences between conventional and auxetic lattices in terms of penetration characteristics and deformation energy mitigation properties. Dynamic penetration of the samples is performed using a fully strain‐gauge instrumented open Hopkinson pressure bar at three impact velocities resulting in three loading scenarios. All the performed experiments are captured by two optical cameras for detailed observation and to track the impactor movement using digital image correlation. The force‐penetration depth relation is used to evaluate the elastic and postyield compression characteristics of the lattices together with their deformation energy mitigation capabilities. The results show that the main differences in the deformation response of the lattices consist of lower overall stiffness and effective yielding of the auxetic lattices at a higher penetration depth. Numerical simulation using an explicit solver is performed to analyze the deformation mechanism of the individual core types. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
- Full Text
- View/download PDF
42. Scaling of bi-material sandwich panels subjected to impact loadings.
- Author
-
Al-Tamimi, Anees
- Abstract
Scaling is a widely used concept in impact and explosion engineering which is mainly utilized to predict the response behaviour of large-scale mechanical structures by conducting experiments on scaled trial models. However, the practical application of currently available conventional scaling methodologies for impact and explosive processes are significantly restricted by their inability to properly capture the scale effects of strain rate and strain hardening. Also, they are suffering from an insufficient number of independent degrees of freedom. Furthermore, the zeroth-order finite similitude theory, which can annihilate the non-scalability of rate and hardening effects, doesn't provide us with efficient scaling methods when the investigated structure is made out of different materials. More precisely, the zeroth-order finite similitude theory and the classical dimensional analysis, which are suffering from a limited number of independent degrees of freedom, cannot scale the elastic-plastic behaviour represented by different parts of a structure made out of different materials. In other words, classical scaling methodologies including dimensional analysis and even the zeroth-order finite similitude theory cannot fix two different features having the same unit using different degrees of freedom, which make them useless for structures made of more than one material such as bi-material sandwich panels. In the presented paper, a new scaling methodology is developed based on the recently proposed first-order finite similitude theory which for the first time enables us to capture the rate dependent plastic behaviour of an impacted structure made out of two different materials. A sandwich panel made of two different materials which is subjected to an impact loading is considered as the case study in order to investigate the efficiency of the proposed first-order based scaling technique. The numerical results are determined using Abaqus finite element software in which the Johnson-Cook constitutive equation is utilized to take into account the rate and hardening effects on the initial yield stress. The results reveal that the behaviour of impacted full-scale bi-material sandwich panels can be predicted with a high accuracy when the extra degree of freedom provided us with the first-order finite similitude (i.e. R
1 ) is set to vary between −1 and 1 (i.e. − 1 ≤ R 1 ≤ 1). Furthermore, it is found that the pure mechanical and thermo-mechanical behaviour of the impacted core honeycomb are highly accurately predicted using scaled-down trial models which are made from dissimilar materials and designed based on the zeroth-order finite similitude theory. [ABSTRACT FROM AUTHOR] more...- Published
- 2023
- Full Text
- View/download PDF
43. Zum Biegeknicken von Sandwichelementen.
- Author
-
Janczyk, Kevin, Nonn, Jonas, Kuhnhenne, Markus, and Feldmann, Markus
- Subjects
- *
SANDWICH construction (Materials) , *AXIAL loads , *WALL panels , *BUILDING envelopes , *COLD storage , *COMMERCIAL buildings , *ENGINEERING standards , *COOLING systems - Abstract
On the flexural buckling of sandwich panels Sandwich panels are one of the leading systems for building envelopes in industrial and commercial construction. Other areas of applications are cold storage rooms, which are realized exclusively from sandwich panels without any substructure or primary structure. Thereby, the sandwich panels, which are used as wall panels, are subjected to axial loads. A design concept of sandwich panels under axial loading based on stress verifications can be found in the draft of the new Eurocode 3 standard EN 1993‐7 "Design of steel structures – sandwich panels". A design concept based on the geometrical and structural imperfections and the actual load‐bearing capacity of the panels is neither included in the literature nor in the draft of the new standard. In the present work, investigations on flexural buckling of sandwich panels are presented. A method is presented which can be used in the future for the development of buckling curves of sandwich panels. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
- Full Text
- View/download PDF
44. Experimentelle Untersuchungen an Sandwichfassaden als Grundlage für deren Erdbebenauslegung: Versuche an Sandwichelementen bei Erdbebenbelastung in Fassadenebene.
- Author
-
Bittner, Lara, Hoffmeister, Benno, and Kuhnhenne, Markus
- Subjects
- *
BUILDING envelopes , *EARTHQUAKE resistant design , *BUILDING performance , *CYCLIC loads , *METAL roofing , *EFFECT of earthquakes on buildings - Abstract
Tests on sandwich façades as a basis for seismic design As part of an ongoing research project, the performance of lightweight metal façade elements under in‐plane loading was investigated to assess their cyclic behavior, dissipation capacity and functionality during seismic events. As preliminary investigations showed, metal wall and roof elements contribute to the stiffening of the overall structure, and thus to the change of the eigen period compared to the primary structure, which can lead to increased seismic loads to be applied acc. to the response spectrum method. Based on this, a new behavior‐based approach considering the contribution of lightweight metal building envelopes can be developed to determine the improved resilience of structures and the effect of a damaging earthquake on the building envelope performance. This paper includes: (i) a brief state of the art, (ii) a presentation of the research project, (iii) the experimental program, (iv) the detailed experimental setup, (v) the system response under monotonic and cyclic loading, (vi) the main results, (vii) an overview of the numerical investigations and ongoing and future research activities. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
- Full Text
- View/download PDF
45. Kühlräume aus Sandwichelementen.
- Author
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Naujoks, Bernd and Ardelmann, Niklas
- Subjects
- *
SANDWICH construction (Materials) , *WAREHOUSES , *STRUCTURAL design , *FOOD storage , *CEILINGS , *WALL panels - Abstract
Cold stores with sandwich panels Cold stores are indoor constructions, which are indispensable for the storage of foods. The rising demand for larger storage‐spaces in the distribution centers of the food‐retailers lead to steel‐lightweight cold stores with dimensions of L × W × H = 50 m × 20 m × 16 m, which require a proper structural design. Because of their excellent insulating properties, mainly sandwich panels are used for the construction of cold stores. The detailed designs are demanding, as they require comprehensive thermal and executional optimization. Hence, they often need to be considered in the design and calculation process. The ceiling and wall panels may be considered as diaphragms for the spatial stiffening if the corresponding design and execution rules are respected. If in addition, the wall elements, transferring the ceiling loads, are designed regarding the additional stresses due to second order theory, cold rooms made of sandwich panels, may be carried out without any substructure. The draft of the new standard – prEN 1993‐7 "Design of steel structures – sandwich panels" – provides a corresponding design method. Proven execution details and calculation examples for panels as diaphragms and compression supports are explained below. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
- Full Text
- View/download PDF
46. Leichte Dach‐ und Wandbauteile mit einem Kern aus natürlichen Rohstoffen: Ressourcenschonung und Reduktion des CO2‐Ausstoßes.
- Author
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Lange, Jörg, Pradhan, Eric Man, Renaux, Thibault, Gervásio, Helena, Olano, Xabier, Huet, Valérie, and Izabel, David
- Subjects
- *
SANDWICH construction (Materials) , *LIGHTWEIGHT steel , *MILD steel , *CARBON emissions , *WOOD , *THERMAL insulation , *NUCLEAR fuel claddings - Abstract
Lightweight building steel envelop systems with bio‐based insulation – conservation of resources and reduction of CO2 emissions The aim of the research project presented below is to develop five building envelope systems made of low‐carbon steel and innovative use of wood fibre insulation. Three sandwich panels (pitched roof, flat roof, façade), a double‐skin façade and a façade cladding (cassettes) will be developed. The project includes a series of tests to investigate all relevant properties of the systems: load‐bearing behavior, fire behavior, thermal insulation, acoustics, air‐, water‐ and vapor‐permeability. In addition, two full‐scale prototypes were built to study the behavior of the systems under real conditions. The determination of LCA indicators and a comparison in terms of carbon footprint (GWP) with conventional systems using an existing office building as a reference will also be carried out. An economic comparison between the expected delivery and installation price of the five innovative systems and that of the existing conventional systems is planned. The production of the sandwich panels can be easily integrated into the current production lines. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
- Full Text
- View/download PDF
47. Investigating Mechanical Properties of Alkali-Activated Slag Cementitious Material for Load-Bearing Layer of Sandwich Panels.
- Author
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Zhu, Jing, Qu, Zijian, Huang, Ying, Song, Lizhuo, Liu, Shaotong, Min, Hao, and Li, Zhiming
- Subjects
- *
SANDWICH construction (Materials) , *SLAG , *THERMAL insulation , *MAGNESIUM oxide - Abstract
The research presented in this paper is about the mechanical properties of fiber-reinforced alkali-activated slag cementitious sandwich panels with different types and amounts of admixtures. The mechanical properties, drying shrinkage properties, and micro-morphology were used to determine the optimal ratio of the admixtures. The results show that the alkali-activated slag sandwich panels have the characteristics of light weight, high strength and excellent thermal insulation, and the factors such as magnesium oxide, expansion agent and solution temperature have significant influence on their mechanical properties and dry shrinkage. This paper provides a theoretical basis and experimental data for the preparation process and application of alkali-activated slag sandwich panels. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
- Full Text
- View/download PDF
48. Investigations on the stability behaviour of axially loaded sandwich panels with integrated longitudinal profiles.
- Author
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Janczyk, Kevin and Kuhnhenne, Markus
- Subjects
SANDWICH construction (Materials) ,AXIAL loads ,BEND testing - Abstract
This paper presents investigations on the load‐bearing behaviour of sandwich panels under bending load and axial load. The sandwich panels investigated here have the special feature that they consist of two face sheets, a polyurethane core and two integrated reinforcement profiles. These integrated profiles allow the stiffness of the panels to be significantly increased, resulting in a delayed wrinkling failure and thus opening up new fields of application. Experimental results from bending tests are presented. From these results, analytical approaches are then described that can be used to predict the load‐bearing behaviour under axial loading. In addition, the test setup is described, which will be used in the future for the experimental investigation of the panels under axially loading. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
- Full Text
- View/download PDF
49. Sandwich Panels as Building Envelope under In‐Plane Deformation: Experimental Program and Monotonic / Cyclic Response.
- Author
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Bittner, Lara, Vulcu, Cristian, and Hoffmeister, Benno
- Subjects
SANDWICH construction (Materials) ,BUILDING envelopes ,LIGHTWEIGHT construction ,DEFORMATIONS (Mechanics) ,CYCLIC loads ,EFFECT of earthquakes on buildings ,FACADES ,BUILDING-integrated photovoltaic systems - Abstract
Strong earthquake loads can cause significant damage to buildings, but even moderate earthquakes with higher return periods are socially relevant as they may cause both infrastructure and economic failures. In an ongoing German nationally funded research project, the behavior of facade elements in lightweight metal construction under in‐plane deformation is currently being investigated with the aim to assess the response and the energy dissipation capacity in the case of seismic events. As past research results indicate the contribution of wall and roof elements to the stiffening of buildings, with the possible consequence of increased earthquake loads due to the natural frequency change, a novel approach for increased resilience of structures with building envelopes in lightweight metal construction may be developed. On the basis of a series of experimental tests, under monotonic and cyclic loading, the effects of in‐plane deformation were studied separately from external influences such as wind and thermal loads. This paper presents: (i) a brief state of the art; (ii) a description of the research framework; (iii) the experimental program; (iv) the specimen configuration, test set‐up, loading protocol and instrumentation; (v) the response under monotonic and cyclic loading; (vi) the main conclusions, as well as the ongoing and future research activities. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
- Full Text
- View/download PDF
50. Influence of Profiled Faces on the Overall Shear Performance of Strongly Profiled Sandwich Panel with Mineral Wool Core.
- Author
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Silwal, Shekhar, Mela, Kristo, and Ma, Zhongcheng
- Subjects
SANDWICH construction (Materials) ,MINERAL wool ,CORE materials ,STRESS concentration ,SHEARING force - Abstract
The total shear force induced on a profiled sandwich panel by an external load is distributed between the profiled face and core. Sandwich panel with a discrete core material such as mineral wool consists of multiple transverse lamella joints across the full width of the panel, affecting the overall shear performance of the panel as these joints have negligible resistance to shear. Additionally, in some cases the core material is partially bonded only to the lower flange of the profiled face which increase the concentration of stresses in the bonded area leading to the crushing of the core on the support. This work studies the distribution of shear force in mineral wool core sandwich panels with one profiled face utilizing a shear beam test on a specimen cut from the panel including the profiled part. Based on the results and failure modes obtained, this work investigates the behavior and role of the profiled face on the shear resistance of profiled sandwich panels. The distributed shear force between the core and profiled part obtained from the shear beam tests are compared with full‐scale tests suggested by the European Standard EN 14509:2013, thus, exploring the applicability of the devised shear beam test method for assessing the shear properties of profiled sandwich panel. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
- Full Text
- View/download PDF
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