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Journal articles on the topic "Tests sandwich"

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Prabhakaran, S., V. Krishnaraj, Hemashree Golla, and M. Senthilkumar. "Biodegradation behaviour of green composite sandwich made of flax and agglomerated cork." Polymers and Polymer Composites 30 (January 2022): 096739112211036. http://dx.doi.org/10.1177/09673911221103602.

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Material experts are striving to use natural resources as skin and core in composite sandwiches to achieve light weight, biodegradability, and cost benefits. This paper reports one such newly developed green composite sandwich and its biodegradable behavior. The skin and core of newly developed sandwich are flax fiber and agglomerated cork respectively. This composite sandwich is manufactured by vacuum bagging technique in order to get higher volume fraction of fiber. The biodegradability testing of the composite sandwich has been executed by soil burial test. The verification of the same has been done using Scanning Electron Microscope (SEM) images, Fourier Transform Infrared Spectroscopy (FTIR) analysis and Thermoanalytical test. The test results portray the percentage of weight loss in the specimens and that, it increases with burial time. It also depicts that the newly developed Green Composite Sandwich (GCS) has 82% higher degradation than the Synthetic Composite Sandwich (SCS) taken for the comparison. SEM images show that the green composite sandwiches have lost their fibrous structure and cell wall surface due to the degradation. FTIR and Thermoanalytical tests also confirm the biodegradability of the developed green composite sandwich.
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Lin, Zhengjie, Hengliang Liang, and Hongfei Zhou. "Forming pressure of PMI foam sandwich structure." Journal of Physics: Conference Series 2566, no. 1 (August 1, 2023): 012040. http://dx.doi.org/10.1088/1742-6596/2566/1/012040.

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Abstract In this study, the performance of A-reinforced sandwich structures made with polymethacrylimide (PMI) foam material is explored. The research focuses on comparing two forming methods, bonding and co-curing. It also tests the static properties of sandwich test pieces under different forming pressures. It reveals that the foam sandwich structure formed under the 0.15 MPa bonding process outperforms the rest regarding static properties. These findings provide valuable insights into the optimal structure-forming process for PMI foam sandwiches, paving the way for future advancements in this field.
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Li, Zhao, Hao Zhang, Qingyong Niu, Peng Wang, and Xiaoming Cao. "Design of double-layered framed plate with equivalent impedance." MATEC Web of Conferences 380 (2023): 01018. http://dx.doi.org/10.1051/matecconf/202338001018.

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To get clear the vibration mechanism of sandwith shell using the experiment method, a double-layered plate is designed for the sandwich shell by matching the equivalent impedance. Numerical analysis is conducted, and In 10Hz-4000Hz, the differenceof impedance from double-layered plate and sandwich shell should be less than 10%. A new design is given for the double-layered plate, and which is quite simple for construction. Then, the double-layered plate could be applied to conduct series vibration tests to get clear the influence of sandwich core material on structural vibration, while it could also reduce the costs of money and construction time.
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Zhang, Zhen, Jian Guang Zhang, Xiu Zhi Liu, Yong Hai Wen, and Shao Bo Gong. "Numerical and Experimental Studies of Composites Sandwich Structure with a Rectangular Cut-Out." Applied Mechanics and Materials 395-396 (September 2013): 891–96. http://dx.doi.org/10.4028/www.scientific.net/amm.395-396.891.

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Numerical and experimental study on honeycomb sandwich structure with a rectangular cut-out were carried out in this paper. Two designs were presented, with using a U-shaped sandwich structure or a combination of two separate sandwiches. Finite element models were developed and calculated using MSC.NASTRAN code by means of linear analysis and non-linear incremental deformation analysis. Compared with linear analysis, non-linear analysis was more suitable to evaluate the ability of sandwich structure with cut-out to resist compressive load. The results obtained from non-linear solution were verified by the supporting mechanical tests.
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Saifullah, Abu, Pappu Radhakrishnan, Lei Wang, Burhan Saeed, Forkan Sarker, and Hom N. Dhakal. "Reprocessed Materials Used in Rotationally Moulded Sandwich Structures for Enhancing Environmental Sustainability: Low-Velocity Impact and Flexure-after-Impact Responses." Materials 15, no. 18 (September 19, 2022): 6491. http://dx.doi.org/10.3390/ma15186491.

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In the rotational moulding industry, non-used, scrap, and waste purge materials have tremendous potential to be reprocessed and applied in skin-foam-skin sandwich structures to replace and reduce the use of virgin polymers. This approach not only encourages the re-use of these waste materials but also significantly contributes to reduce environmental impacts associated with the use of virgin polymers in this sector. The demand of rotationally moulded sandwich structures is rapidly increasing in automotive, marine, and storage tanks, where investigating their impact and after-impact responses are crucial. Hence, this study investigated the low-velocity impact (LVI) and flexure-after-impact (FAI) responses of rotationally moulded sandwich structures manufactured using reprocessed materials. Results obtained from LVI induced damage at two different incident energy levels (15 J, 30 J), and the residual flexural strength of impacted structures evaluated by three-points bending tests were compared with non-reprocessed sandwich structures (virgin materials). The impact damage progression mechanism was characterized using the X-ray micro-computer-tomography technique. Reprocessed sandwiches demonstrated 91% and 66% post-impact residual strength at 15 J and 30 J respectively, while for non-reprocessed sandwiches, these values were calculated as 93% and 88%. Although reprocessed sandwich structures showed a lower performance over non-reprocessed sandwiches, they have a strong potential to be used in sandwich structures for various applications.
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Kozak, Janusz. "Joints Of Steel Sandwich Structures." Polish Maritime Research 28, no. 2 (June 1, 2021): 128–35. http://dx.doi.org/10.2478/pomr-2021-0029.

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Abstract Steel sandwich structures are perceived as alternatives to single-skin welded structures in the shipbuilding industry due its advantages like significant reduction of mass in relation to typical single skin structure. However, beside problems with their strength properties itself, applications in real structures requires of solving the problem of joining, both for connection sandwich to sandwich as well as sandwiches to single-shell structures. Proper design of joints is connected with some factors like lack of attempt to interior of panel, introduction of additional parts and welds with completely different stiffness. In the paper the results of laboratory fatigue tests of selected joints as well as numerical calculation of stressed for different kind of joints of sandwich structures are presented. As result of calculations optimisation of geometry for selected joints is performed.
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Hosseini, SM, A. Habibolahzadeh, and J. Němeček. "Static and dynamic responses of a novel Al nanocomposite foam/sandwich structure under bending, impact and quasi-static compression tests." Journal of Sandwich Structures & Materials 21, no. 4 (July 3, 2017): 1406–27. http://dx.doi.org/10.1177/1099636217717579.

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The aim of this study is to analyze mechanical properties of a new Al sandwich structure with a foam core reinforced by 0.75 wt% silicon carbide nanoparticles. The reinforced core as the main component of the sandwich structure is examined by nanoindentation, quasi-static compression, impact and three-point bending tests. The behavior of the nanocomposite foam core sandwiched with AA3103 facing sheets is also analyzed under three-point bending test. The results showed that the silicon carbide nanoparticles play an important role in enhancing the Young’s modulus and hardness of the metallic matrix, static compressive strength, energy absorption of the foam core as well as load carrying capacity and maximum deflection of the sandwich structure. However, they have no significant influence on the morphological features, impact and bending properties of the foam core. The effectiveness of the silicon carbide nanoparticles was dependent on the dominant deformation mode and failure mechanism of specimens under the applied loadings.
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Emi Nor Ain Mohammad, Nurul, Aidah Jumahat, and Mohamad Fashan Ghazali. "Impact Properties of Aluminum Foam – Nanosilica Filled Basalt Fiber Reinforced Polymer Sandwich Composites." International Journal of Engineering & Technology 7, no. 3.11 (July 21, 2018): 77. http://dx.doi.org/10.14419/ijet.v7i3.11.15934.

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This paper investigates the effect of nanosilica on impact and energy absorption properties of sandwich foam-fibre composites. The materials used in this study are closed-cell aluminum (Al) foam (as the core material) that is sandwiched in between nanomodified basalt fiber reinforced polymer (as the face-sheets). The face sheets were made of Basalt Fibre, nanosilica and epoxy polymer matrix. The sandwich composite structures are known to have the capability of resisting impact loads and good in absorbing energy. The objective of this paper is to determine the influence of closed-cell aluminum foam core and nanosilica filler on impact properties and fracture behavior of basalt fibre reinforced polymer (BFRP) sandwich composites when compared to the conventional glass fibre reinforced polymer (GFRP) sandwich composites. The drop impact tests were carried out to determine the energy absorbed, peak load and the force-deflection behaviour of the sandwich composite structure material. The results showed that the nanomodified BFRP-Al foam core sandwich panel exhibited promising energy absorption properties, corresponding to the highest specific energy absorption value observed. Also, the result indicates that the Aluminium Foam BFRP sandwich composite exhibited higher energy absorption when compared to the Aluminium foam GFRP sandwich composite.
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Elettore, Elena, Massimo Latour, Mario D’Aniello, Raffaele Landolfo, and Gianvittorio Rizzano. "Prototype Tests on Screwed Steel–Aluminium Foam–Steel Sandwich Panels." Buildings 13, no. 11 (November 13, 2023): 2836. http://dx.doi.org/10.3390/buildings13112836.

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Metal foams are newly developed engineered materials with attractive mechanical properties such as lightness, high resistance-to-weight ratio, and insulation capabilities. Lately, applications of these technologies have demonstrated the possibility of obtaining high-performance sandwich panels with steel skins and metal foam core, with potential applications across various fields. Within this framework, this work aims to assess the response of sandwich panels made of steel and aluminium foam to develop a new system of dry-assembled composite floors. The present study investigates a novel screwed steel–aluminium foam–steel (SSAFS) sandwich panel. This paper mainly describes and discusses the results of experimental tests devoted to evaluating the structural performance, mechanical properties, and suitability for practical applications of SSAFS. The fabrication process and the detailing of the steel skins and aluminium foam core assembly are also described. The results from the experimental tests revealed the potentialities of using SSAFS sandwich panels in terms of strength and stiffness, thus making them suitable for lightweight structural systems.
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Chróścielewski, Jacek, Marian Klasztorny, Mikołaj Miśkiewicz, Łukasz Pyrzowski, Magdalena Rucka, and Krzysztof Wilde. "GFRP sandwich composite with PET core in shell structure of footbridge." Budownictwo i Architektura 13, no. 2 (June 11, 2014): 183–90. http://dx.doi.org/10.35784/bud-arch.1894.

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The paper presents experimental study of sandwich composite used for an innovative foot-and-cycle bridge. The footbridge has a U-shaped shell structure made of sandwich consisting GFRP laminate covers and foam PET core. The bridge is manufactured using the infusion technology. Results of one and two directional tension tests of the laminates, compression tests of PET foam samples and 3-point as well as 4-point bending tests of sandwich beams are presented.
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Dissertations / Theses on the topic "Tests sandwich"

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Martin, James David. "Sandwich Plate System Bridge Deck Tests." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/31648.

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Three series of tests were conducted on a sandwich plate bridge deck, which consisted of two steel plates and an elastomer core. The first series of testing was conducted by applying a static load on a full scale sandwich plate bridge deck panel. Local strains and deflections were measured to determine the panelâ s behavior under two loading conditions. Next, fatigue tests were performed on the longitudinal weld between two sandwich plate panels. Two connections were tested to 10 million cycles, one connection was tested to 5 million cycles, and one connection was tested to 100,000 cycles. The fatigue class of the weld was determined and an S-N curve was created for the longitudinal weld group. Finally, a series of experiments was performed on a half scale continuous bridge deck specimen. The maximum positive and negative flexural bending moments were calculated and the torsional properties were examined. Finite element models were created for every load case in a given test series to predict local strains and deflections. All finite element analyses were preformed by Intelligent Engineering, Ltd. A comparison of measured values and analytical values was preformed for each test series. Most measured values were within five to ten percent of the predicted values. Shear lag in the half scale bridge was studied, and an effective width to be used for design purposes was determined. The effective width of the half scale simple span sandwich plate bridge deck was determined to be the physical width. Finally, supplemental research is recommended and conclusions are drawn.
Master of Science
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Grigg, William Reid. "Post-Injection Welded Joint Fatigue Tests of Sandwich Plate System Panels." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/44900.

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The Sandwich Plate System (SPS) is created by bonding two steel plates together with an elastomer core that is injected into a cavity formed by the steel plates and perimeter bars. The result is a stiffer and lighter panel that can be used for plate-like structures such as bridge decks, stadium risers or ship decks. For more versatility, the effects of welding post-injection to the SPS panels were investigated. Three post-injection welded joints were tested to determine fatigue resistance and the effects of cyclic loading on the localized debonding of the heat affected zone at the post-injection welded joint of a SPS bridge deck. Seven panels containing one of three post-injection weld configurations were investigated. Each panel was fatigue tested to ten million cycles or until failure, by applying remote bending to the post-injection welded joint. Experimental deflections and strains were compared to finite element analyses. Fatigue-life predictions were made using code based S-N curves, and a relatively new mesh-insensitive structural stress method with a master S-N curve approach. The post-injection welded joint demonstrated good fatigue resistance to recommended AASHTO loading when shims were used under the middle support to offset the camber in the SPS panels. It was also found that stresses caused by draw down of the camber had an adverse affect on the post-injection welded joint and greatly reduced its fatigue resistance.
Master of Science
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Foster, Andrew. "Understanding, predicting and improving the performance of foam filled sandwich panels in large scale fire resistance tests." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/understanding-predicting-and-improving-the-performance-of-foam-filled-sandwich-panels-in-large-scale-fire-resistance-tests(3dc4bf07-82f0-4e3e-9cab-37e9244fe2a2).html.

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This thesis presents the results of research on sandwich panel construction, with the aims of developing tools for modelling sandwich panel fire performance and hence to use the tools to aid the development of sandwich panel construction with improved fire resistance. The research focuses on sandwich panels made of thin steel sheeting and a polyisocyanurate (PIR) foam core. For non-loadbearing sandwich panel construction, fire resistance is measured in terms of thermal insulation and integrity only. However, these two parameters are affected by mechanical performance of sandwich panel construction due to the high distortion and large deformation nature of sandwich panel construction under fire attack. Therefore, it is necessary to consider both thermal and mechanical performances of sandwich panels under fire conditions. The work in this thesis includes development of a thermal conductivity model for PIR foam as this thermal property is one of the key values in determining heat transfer through sandwich panels; this thermal conductivity model is based on the effective thermal conductivity of porous foams proposed by Glicksman (1994) and includes the effects of polymer decomposition and increases in foam cell size. It is validated against fire tests carried out on PIR sandwich panels 80mm and 100mm thick with steel facings of thickness 0.5mm. A large 3D sequentially coupled thermal-stress model of a full scale fire test has been developed in the commercial finite element analysis (FEA) software ABAQUS to provide insight into the way sandwich panels behave in a fire resistance test and also to assess different modelling techniques. Aspects and stages of the simulation that agree well with test data are explained. Limitations of the ABAQUS software for simulating sandwich panel fire tests are highlighted; namely, it is not possible to simulate the correct radiation heat transfer through panel joints, as cavity radiation cannot be specified in a fully coupled thermal-stress analysis. Joints are key components of sandwich panel construction. In order to obtain temperature development data for modelling joints, a number of fire tests have been carried out. These fire tests were conducted with different joint configurations and panel thicknesses under realistic fire conditions using timber cribs. The joint fire tests revealed significant ablation of the foam core within the joints of sandwich panels at high temperatures. At the beginning of fire exposure, the joint temperature on the unexposed surface was lower than that on the panel due to the better insulation property of air compared to the foam. However, as the joint gap increased due to ablation of the foam, the joint temperatures became higher than in the panel. A numerical simulation model has been created to investigate this behaviour. Using the aforementioned thermal model, numerical simulations have been carried out to examine the influences of possible changes to sandwich panel design on sandwich panel construction fire performance. It was suggested that if the maximum gap in the joints can be limited to 5mm, for example, by applying intumescent coating strips within the sandwich panel joints to counter the increasing gap formed due to core ablation, then the joint temperature on the unexposed surface would not exceed that of the panel surface, hence the joint would cease to be the weak link. To increase the panel fire resistance, the use of graphite particles in the PIR foam formulation may be considered to lower the contribution of radiative heat transfer within the foam cells by reducing the transmissivity of the cell walls. Graphite particles may offer considerable increases in the thermal resistance of PIR foam at high temperatures by limiting the radiation contribution which dominates heat transfer above 300oC.
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Freitas, Nuno Rodolfo Gomes. "Sandwich test para avaliação de grouts." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/14959.

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Mestrado em Engenharia Civil
A presente dissertação visa estudar métodos de ensaio para avaliar as características de grouts não estruturais a utilizar na consolidação de revestimentos de edifícios com destacamento de uma/várias camadas. Neste sentido, foi realizado o ensaio sandwich para simulação de destacamento de camadas. É introduzida uma nova variante deste ensaio seguindo as normas europeias e realizados os ensaios de referência. Apresenta-se a metodologia adotada e faz-se a exposição, comparação, análise e justificação dos ensaios e retiram-se as conclusões bem como os desenvolvimentos futuros.
This thesis aims to study test methods for evaluating the characteristics of non-structural grouts to be used for consolidation of buildings coatings with detachment of one or several layers. Thus, we performed the sandwich trial for layers detachment simulation. A new variant of this essay following the European standards is introduced and reference trials are done. The methodology adopted, exposure, comparison, analysis, trials justification, conclusions taken and future developments are shown.
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Lien, Fredrik. "Modelling and Test Setup for Sandwich Radomes." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elektronikk og telekommunikasjon, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26233.

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Sandwich radomes are structures providing communication- and radar antennas with protection from the environment. The sandwich materials are designed to affect the electromagnetic radiation as little as possible with respect to transmission- and reflection loss, boresight error, boresight error slope, increased sidelobe levels and depolarization. In order to match the frequency response of the radome material to the specifications, simulation and optimization of the thickness and dielectric properties of the individual sandwich layers is done.To simulate the transmission- and reflection coefficients for sandwich materials a Matlab scripts has been developed. The script calculate the response for up to 10 different layers for incidence angles and frequencies defined by the user. Verification of the results has been done by comparing the simulated data to results in Kozakoff (2010) and show that the script works correctly.Waveguide measurement and calibration components have been designed and manufacturedin order to measure samples of dielectric materials and samples of complete radome sandwich materials. The results have been compared to results from simulations done in CST Microwave Studio and show a good match for complete sandwich materials and thicker dielectrics. However the measurement results for thin material samples show more deviation compared to the simulation results. The deviation seems to be dependent on the thickness of the sample.Two optimization routines have been developed in Matlab. The first compare the measuredresults from measurements to the simulated results from Matlab. Least square optimization is used to adjust the dielectric properties (relative permittivity and dielectric loss tangent) used by the simulation script in order to match the simulation values to the measured values. The results show good match of the optimized relative permittivity for a 22 mm thick sample of Teflon with the optimized value deviating 1.3% from the specified permittivity value. With decreasing thickness of the test samples the deviation increased to approximately 3-12%. The optimized loss tangent values however show very large deviation from the specified values and should be treated as invalid. The main reasons are believed to be the low loss of the materials combined with the thickness relative to the measurement wavelength.The second optimization routine adjust the thickness of the individual layers to achieveminimum loss for one- or more predefined frequency bands. The results show that theoptimization work as intended. To investigate the effect of production errors/productiontolerances the core thickness of an A-sandwich has been adjusted with +/-10% from theoptimized thickness. The result show that the thickness deviation has a bigger impact onhigh frequencies.
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Krödel, Jonsson Viktor. "Burst test analysis of metal sandwich wall panels." Thesis, KTH, Lättkonstruktioner, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-180456.

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In this report, an investigation of some of the most common damage models available in literature is performed. Their ability to predict ductile failure of metals will be compared and a specific focus is put on burst failure prediction of the cooling channels inside a sandwich wall structure. This structure is intended to be used at future versions of the Ariane rocket nozzles developed at GKN-Aerospace in Trollhättan, Sweden. Currently GKN-Aerospace uses a prediction method of burst failure based on the Rice and Tracey damage model but it has been shown to sometimes deviate from experimental results, why they seek for a new method to predict ductile failure. Hence the objective of this project is to find a more accurate method to predict burst failure of the sandwich wall than the one used today at GKN-Aerospace. This will be done by both a literature research and performing simulations with the studied damage models.  The project was demarcated to investigate four damage models; the Gurson-Tvergaard-Needleman, Johnson-Cook, the Extended Mohr Coulomb criterion and the currently used damage model at GKN-Aerospace. Further the simulations were delimited to the softwares ANSYS APDL and LS-DYNA, for which burst test simulations was only performed in ANSYS APDL. It was found that only the Gurson-Tvergaard-Needleman and the Rice and Tracey based model could be used for prediction of burst failure in ANSYS APDL, why only those damage models could be evaluated against the objective of the project. The burst test simulation results showed that the Rice and Tracey based model gave predictions of burst pressure closest to experimental results, why the objective of the project was not met since a more accurate prediction method was not found. However important conclusions could be drawn and valuable recommendations for future work could be given.
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Melrose, Paul Thomas. "Elastic Properties of Sandwich Composite Panels Using 3-D Digital Image Correlation with the Hydromat Test System." Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/MelrosePT2004.pdf.

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Bois-Grossiant, Philippe Carleton University Dissertation Engineering Mechanical and Aerospace. "Boundary element fracture mechanics analysis of sandwich test specimens." Ottawa, 1994.

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Li, Nan. "Identification des paramètres mécaniques de plaque sandwich cousue par essais vibratoires." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2361.

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L'objectif des travaux exposés dans cette thèse est d'identifier les différentes propriétés des constituants du sandwich cousu in-situ. Cette identification est indispensable pour simuler le comportement de ce type de matériau composite à différentes sollicitations statiques ou dynamiques. Nous proposons dans cette thèse de faire Une identification dynamique faite sur un échantillon représentatif (une plaque) qui prend en compte l'hétérogénéité et complexité de la structure. Cette identification est basée sur la corrélation ent.re un essai vibratoire et un calcul par éléments finis. La corrélation se fait en minimisant une fonction coût qui porte sur le décalage entre fréquences propres expérimentales et numériques. Cette minimisation est précédée par une identification du couple (fréquence propre/mode propre) numérique et expérimental en utilisant le MAC (Modal Assurance Criterion). Pour optimiser, nous passons, dans un premier temps; par une analyse de sensibilité qui permet de classifier les paramètres en fonction de• leur importance et ainsi ne lancer le processus d'identification que sur un nombre réduit de paramètres. Nous avons appliqué cette approche sur une poutre sandwich cousue et une plaque sandwich cousue. Dans une deuxième partie de ce travail de thèse, nous avons pu mettre au profil l'aspect périodique de ces structures composites sandwichs cousues, en utilisant le théorème de Floquet­-Bloch, et cela sur deux plans : l'aspect numérique pour la réduction du modèle et du temps de calcul et sur le plan physique par l'étude des bandes d'arrêt ('stopband') qui ont un intérêt applicatif assez intéressant
The sandwich structures are well known for their high bending stiffness. This type of structure is also capable of including acoustic and thermal functionalities. However, they also have weaknesses such as the connection between the faceplate and the core and the weakness in the transverse direction due to the property of the core. The core is usually made of soft materials like foam for acoustic functionality. To overcome these weaknesses, it is possible to connect the different layers of the sandwich by transverse stitches. This is the concept of ‘stitched sandwich’. The stitch will deeply change the behavior of the structure and complicate the determination of its properties. The objective of this thesis is to identify the properties of the constituents of the stitched sandwich in situ. These properties are essential to simulate the behavior of this type of composite material under static or dynamic excitation. The identification of the properties of the constituents by mechanical tests is difficult for various reasons: the heterogeneity makes it complex to extract representative specimen; the behaviors of the constituents may change in non-in-situ tests; several different types of mechanical test, such as tensile-compression and torsion, are necessary to determine all the engineering constants in the case of orthotropic material which is common for composite materials. To overcome all these difficulties, we propose in this thesis a dynamic identification method conducted on the structure (the whole plate for example). Compared to mechanical test which is based on a sample, this method takes into account the heterogeneity and complexity of the structure. This method is based on the correlation between the vibration test and a finite element model of stitched sandwich. The parameters are identified by minimizing a cost function which can measure the gap between the experimental frequencies and the calculated frequencies. The correspondence of experimental mode and calculated mode is guaranteed by MAC (Modal Assurance Criterion). Before the optimization, we propose firstly a sensitivity analysis to classify the parameters according to their importance. Then the identification process is only conducted on a reduced number of parameters. We have applied this dynamic identification method to both a stitched sandwich beam and a stitched sandwich plate. 9 parameters of different constituents are identified in the case of plate. In the second part of this thesis, based on the theorem of Floquet-Bloch, we have profited from the periodic characteristic of the stitched sandwich structures in two aspects: in the numerical aspect, the periodicity has served to reduce the calculation of forced response of periodic structure; in the physical aspect, we have studied the stop band of stitched structures
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Junior, Mauricio Francisco Caliri. "Modelos de material para espumas poliméricas aplicadas a estruturas aeronáuticas em material compósito sanduíche." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/18/18148/tde-15082011-223452/.

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Estruturas aeronáuticas são em sua grande parte fabricadas em material compósito para que sejam atendidas as especificações de projeto. Entre essas estruturas destaca-se a estrutura sanduíche. A utilização desse tipo de estrutura requer estudos extensos em novos materiais, bem como na aplicação dos mesmos. Uma atenção especial para o núcleo dessas estruturas é necessária, pois este material é na verdade uma estrutura celular, como as espumas poliméricas. Esta dissertação busca concatenar a literatura com a prática ao estudar a calibração de modelos de material para descrever o comportamento mecânico de espumas poliméricas, bem como avaliar suas potencialidades e limitações. Estas espumas são estruturas celulares cujos mecanismos de falha consistem em respostas micro e macroscópicas. A identificação e quantificação desses comportamentos podem ser feitas através da investigação de modelos de material micro-mêcanicos ou fenomenológicos (macro-mecânicos) associados a ensaios e análises experimentais tanto do material celular quanto da estrutura na qual este material é utilizado. Cada abordagem, micro ou macro-mecânica, possui vantagens e desvantagens que no presente trabalho são discutidas para o material estudado (espuma polimérica rígida de PVC, poli-cloreto de vinila, com estrutura de células fechada e densidade de 60kg/m³). Uma série de ensaios experimentais com bases em normas é realizada e os dados coletados são comparados com dados obtidos simultaneamente através de uma técnica de correlação de imagens. Todas as informações experimentais são confrontadas e associadas aos mecanismos de falha da espuma polimérica. Finalmente, os dados experimentais são utilizados nas identificações de parâmetros de modelos de material disponíveis em um programa comercial de elementos finitos - ABAQUS. Com os modelos de material calibrados, o presente trabalho investiga a representatividade e as limitações dos mesmos quando aplicados a estruturas aeronáuticas submetidas a cargas localizadas, monotônicas ou não. Observou-se que há uma forte dependência da resposta macroscópica da espuma com sua estrutura celular quando submetida a cargas localizadas e/ou não-monotônicas. Ademais, o uso de modelos de material simplificados, e/ou com hipóteses de implementação, gera resultados duvidosos quando estes modelos são aplicados a materiais celulares com respostas complexas (mecanismos micro-mecânicos, anisotropia, viscosidade, etc.). Todavia, o presente trabalho mostra que uma calibração estratégica relevando as hipóteses de implementação e as limitações do modelo de material, fornece bons resultados macroscópicos que são fortemente influenciados pelos mecanismos de falha micro-mecânicos.
Aircraft structures are mostly made of composite material in order to achieve the specifications of a project. Among these structures one highlights the sandwich structure. The usage of this structure requires extensive studies on new materials as well as on the application of these very materials. A special attention for the cores material of these structures is needed because it is in fact a cellular structure, as the polymeric foams. This dissertation seeks to concatenate the literature and practice, studying the calibration of material models to describe the mechanical behavior of polymeric foams, as well as to analyse their potentials and limitations. These foams are cellular structures whose failure mechanisms comprise micro and macro responses. The identification and quantification of these behaviors can be done through micro-mechanical or phenomenological (macro-mechanical) material models along with experimental tests and analyses of both the cellular material and the structure in which this material is used. Each approach, micro or macro, has advantages and disadvantages that in the present work are discussed for the studied material (PVC, poly-vinyl-chloride, rigid closed-cell polymeric foam with a density of 60kg/m³). A series of experimental tests based on standard procedures are carried out and the data collected are compared with data obtained simultaneously through an image correlation technique. All the experimental information are confronted and associated to the failure mechanisms of the polymeric foam. Finally, the experimental data are used for the identification of material models parameters, currently available in the commercial finite elements software - ABAQUS. With the material models calibrated, the present work investigates the representativeness and the limitations of these very models when applied to aircraft structures submitted to monotonic or not localized loads. One has observed that there is a strong dependence of the foams macroscopic response with its cellular structure when it is submitted to localized and/or non-monotonic loads. Moreover, the usage of simplified material models, and/or with some implementation hypotheses, renders doubtful results when these models are applied to cellular materials with complex responses (micro-mechanical mechanisms, anisotropy, viscosity, etc.). Nevertheless, the present work shows that a strategic calibration taking into account the implementation hypotheses and the limitations of the material model, yields good macroscopic results that are strongly influenced by the micro-mechanical failure mechanisms.
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Books on the topic "Tests sandwich"

1

McGowan, David M. Damage characteristics and residual strength of composite sandwaich panels impacted with and without compression loading: Presented at the 39th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, session no. 15--damage tolerance : Long Beach, California, April 20-23, 1998. [Washington, DC: National Aeronautics and Space Administration, 1998.

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Perotti, Giovanni, ed. Sega Mega Drive Game Secrets: Strategie e Segreti, Volume 3. Via Rosellini, Milano, Italy: Jackson Libri, 1993.

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Perotti, Giovanni, ed. Sega Mega Drive Game Secrets: Strategie e Segreti, Volume 2. Via Rosellini, Milano, Italy: Jackson Libri, 1993.

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Perotti, Giovanni, ed. Sega Mega Drive Game Secrets: Strategie e Segreti, Volume 1. Via Rosellini, Milano, Italy: Jackson Libri, 1993.

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Arnold, J. Douglas. Awesome Sega Genesis Secrets II. Lahaina, HI: Sandwich Islands Publishing, 1993.

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Room temperature and elevated temperature composite sandwich joint testing. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1998.

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National Aeronautics and Space Administration (NASA) Staff. Ambient Temperature Fatigue Tests of Elements of an Actively Cooled Honeycomb Sandwich Structural Panel. Independently Published, 2018.

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Jacobs, Samantha E., Catherine B. Small, and Thomas J. Walsh. Fungal diseases of the respiratory tract. Edited by Christopher C. Kibbler, Richard Barton, Neil A. R. Gow, Susan Howell, Donna M. MacCallum, and Rohini J. Manuel. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198755388.003.0030.

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Fungal respiratory infections are important causes of morbidity and mortality in immunocompromised patients. Invasive aspergillosis remains the most common invasive fungal infection whereas other filamentous fungi, such as Fusarium spp., Mucorales, and Scedosporium spp., are increasing in frequency, particularly in neutropenic hosts. Endemic mycoses, including those due to Histoplasma capsulatum, Coccidioides spp., and Talaromyces marneffei, are increasingly prevalent in patients with cell-mediated immunodeficiencies in respective geographic regions. Culture remains the gold standard of diagnosis but has limited sensitivity and often requires invasive procedures. Non-invasive diagnostic tests, including the serum sandwich enzyme immunoassay for the detection of galactomannan, the (1→3)-β‎-D-glucan assay, and molecular amplification methods have been developed to facilitate early and accurate diagnosis. Successful therapy depends upon early initiation of antifungal agents and reversal of immunosuppression. Lipid formulations of amphotericin B and newer generation triazoles including voriconazole, posaconazole, and isavuconazole have expanded the ability to treat multi-drug resistant pathogens more effectively and with less toxicity.
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Book chapters on the topic "Tests sandwich"

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Chroscielewski, Jacek, Mikolaj Miskiewicz, Lukasz Pyrzowski, Magdalena Rucka, Bartosz Sobczyk, Krzysztof Wilde, and Blazej Meronk. "Dynamic Tests and Technical Monitoring of a Novel Sandwich Footbridge." In Conference Proceedings of the Society for Experimental Mechanics Series, 55–60. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-12115-0_8.

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Toso-Pentecote, Nathalie, and Alastair Johnson. "Impact Damage in Sandwich Composite Structures From Gas Gun Tests." In Experimental Analysis of Nano and Engineering Materials and Structures, 771–72. Dordrecht: Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-6239-1_383.

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Xue, Weichen, Ya Li, Jialin Yang, Kai Fu, and Zhijie Li. "Tests of new type of precast sandwich panel with FRP connectors." In Insights and Innovations in Structural Engineering, Mechanics and Computation, 1471–76. Taylor & Francis Group, 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742: CRC Press, 2016. http://dx.doi.org/10.1201/9781315641645-241.

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Górski, M. "Experimental tests of sheeting made of sandwich panels acting as a diaphragm." In Modern Trends in Research on Steel, Aluminium and Composite Structures, 215–21. London: Routledge, 2021. http://dx.doi.org/10.1201/9781003132134-25.

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Paimushin, Vitaly N., Ruslan K. Gazizullin, Natalya V. Polyakova, and Maksim A. Shishov. "Sandwich Shells with Composite Facings and a Transversally Flexible Core: Refined Equations and Buckling Modes of Specimens Under Four-Point Bending Tests." In Multiscale Solid Mechanics, 391–411. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-54928-2_29.

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Hildebrand, Martin. "Penetrating Impact Strength of Sandwich Panels — Meaningful Test Method and Simplified Prediction." In Mechanics of Sandwich Structures, 247–54. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-015-9091-4_29.

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Lee, Jong Woong, Cheol Won Kong, Se Won Eun, Jae Sung Park, Young Soon Jang, Yeong Moo Yi, and Gwang Rae Cho. "Compression Test of Composite Sandwich Panel." In Advances in Fracture and Damage Mechanics VI, 605–8. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-448-0.605.

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Davies, Peter, Benoît Bigourdan, Dominique Choqueuse, Nicolas Lacotte, and Bertrand Forest. "Development of a Test to Simulate Wave Impact on Composite Sandwich Marine Structures." In Dynamic Failure of Composite and Sandwich Structures, 177–208. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-5329-7_5.

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Kun, Yang, Yan Qun, and Xu Fei. "Simulation and Test Study on Composite Honeycomb Sandwich Panel." In Lecture Notes in Electrical Engineering, 368–79. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-7652-0_34.

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Hamitouche, Lotfi, Mostapha Tarfaoui, and Alain Vautrin. "Design and Test of a Sandwich T-Joint for Naval Ships." In Damage and Fracture Mechanics, 131–41. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-90-481-2669-9_14.

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Conference papers on the topic "Tests sandwich"

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Haffke, Marcin M., Matthias Pahn, and Catherina Thiele. "Fire Tests on the Pre-cast Concrete Sandwich Walls with GFRP Connectors." In IABSE Symposium, Guimarães 2019: Towards a Resilient Built Environment Risk and Asset Management. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/guimaraes.2019.0759.

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<p>Precast concrete sandwich panels are known for their inherently good thermal, acoustic and structural properties. When using glass fibre reinforced polymeric (GFRP) connectors coupling the concrete layers, excellent thermal properties and high structural stiffness can be achieved. However lack of knowledge on fire resistance of sandwich panels and fire bahavior of GFRP connectors remain an important issue limiting their wider use in the construction. This paper presents results of fire tests performed on real size sandwich walls in terms of fire behavior of the GFRP connectors and its impact on fire resistance of the entire walls. All the three tested sandwich walls met the REI 120-M criteria for load-bearing fire walls. The connectors showed in general good fire resistance and did not contribute to fire spread. The tests delivered important information on structural behaviour of sandwich walls with GFRP connectors loaded with fire and vertical eccentric and impact load.</p>
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Şener, Özgün, Oğuzhan Dede, Oğuz Atalay, Mert Atasoy, and Altan Kayran. "Evaluation of Transverse Shear Moduli of Composite Sandwich Beams Through Three-Point Bending Tests." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-87636.

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Transverse shear moduli of the sandwich core and flexural stiffness of all-composite sandwich constructions are determined with three-point beam bending tests, and compared with the analytical and finite element analysis solutions. Additionally, Digital Image Correlation (DIC) system is employed to validate the experimental results by monitoring the displacements. The effect of orientation of the composite core material with respect to the beam axis on the shear modulus of the core material itself, flexural stiffness of the sandwich beam, maximum loading, and the maximum stresses on the sandwich panel are also examined. Comparable results are achieved through experiments, finite element and analytical analyses.
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Ferri, Rocco, and Bhavani V. Sankar. "Static Indentation and Low Velocity Impact Tests on Sandwich Plates." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-0749.

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Abstract Quasi-static indentation tests and drop-weight impact tests were performed on graphite/bismaleimide (GR/BMI) laminates as well as on foam-core sandwich panels. Impact tests on 8-ply laminates show that the response and damage are similar to quasi-static results. Quasi-static and impact test results on sandwich panels show that the overall response is dependent upon the response of the face sheets and the core. An increase in core density increases the overall load level, panel stiffness, core fracture toughness, and decreases the core compression. A decrease in core thickness decreases the panel stiffness and energy absorption. If the radius of the indenter is greater than the core thickness, penetration of the panel will be delayed and the failure load of the bottom face sheet will increase. The quasi-static and impact responses have the same overall trend, however, the load levels increase in impact tests due to dynamic effects.
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"Weathering Tests on Epoxy-Bonded Steel Concrete Open Sandwich Beams." In SP-165: Repair and Strengthening of Concrete Members with Adhesive Bonded Plates. American Concrete Institute, 1996. http://dx.doi.org/10.14359/10058.

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Avery, John L., Manickam Narayanan, and Bhavani V. Sankar. "Compressive Failure of Debonded Sandwich Beams." In ASME 1998 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/imece1998-0380.

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Abstract Compression tests were performed on debonded sandwich beams made of graphite/epoxy face-sheets and aramid fiber honeycomb core. The sandwich beams were manufactured using a vacuum bagging process. The face-sheet and the sandwich beam were co-cured, thus the excess resin from the graphite/epoxy prepregs was used to bond the face-sheet and the core. Delamination between one of the face sheets and the core was introduced by using a Teflon® layer during the curing process. Axial compression tests were performed to determine the ultimate load carrying capacity of the debonded beams. Double Cantilever Beam tests were performed to determine the fracture toughness of the face-sheet/core interface. It was concluded that linear buckling analysis was inadequate for predicting the ultimate loads. A post-buckling analysis was carried out using a nonlinear plane finite element model of the sandwich beam. The ultimate loads predicted by the finite element model were reasonably good for specimens with long delaminations.
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Hoffmann, William F., Gunter Helwig, and Dietmar Scheulen. "Thermal Stability Tests Of CFRP Sandwich Panels For Far Infrared Astronomy." In 29th Annual Technical Symposium, edited by Gregory M. Sanger. SPIE, 1986. http://dx.doi.org/10.1117/12.950384.

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Sun, C. T., R. S. Hasebe, and Y. Hua. "Properties of Sandwich Structures With Reinforced Core." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-0733.

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Abstract Sandwich panels with a Rohacell core reinforced with composite laminates were constructed. The effective properties of the reinforced core were derived and verified by three point bending tests of a sandwich beam. The equilibrium equations for the sandwich plate with the composite reinforced core were derived. Impact experiment was also conducted by use of a drop tower. Damage modes and levels of damage in sandwich panels containing bare and reinforced Rohacell cores were investigated and compared. Several NDI methods were employed to inspect the damage in the sandwich panel and their merits were compared.
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Allison, W. Don. "Shock Tube Tests of a Kevlar Sandwich Panel and Comparison with Theory." In Aerospace Technology Conference and Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1987. http://dx.doi.org/10.4271/871894.

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Gates, Thomas, and Helen Herring. "Facesheet push-off tests to determine composite sandwich toughness at cryogenic temperatures." In 19th AIAA Applied Aerodynamics Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2001. http://dx.doi.org/10.2514/6.2001-1219.

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Schwenke, Johann, Lukas Schwan, Michael Hanna, and Dieter Krause. "Approach for load path optimized design of sandwich structures using virtual tests and realistic test setups." In Proceedings of the 33rd Symposium Design for X. The Design Society, 2022. http://dx.doi.org/10.35199/dfx2022.05.

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Reports on the topic "Tests sandwich"

1

Singleton, Jr., Robert. The Planar Sandwich and Other 1D Planar Heat Flow Test Problems in ExactPack. Office of Scientific and Technical Information (OSTI), January 2017. http://dx.doi.org/10.2172/1340981.

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STUDY ON FLEXURAL CAPACITY OF PROFILED STEEL SHEET - POLYURETHANE SANDWICH SLABS. The Hong Kong Institute of Steel Construction, March 2024. http://dx.doi.org/10.18057/ijasc.2024.20.1.6.

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Widely employed in enveloped structures, the metal-faced sandwich panel boasts thermal insulation, noise abatement, lightweight, and remarkable assembly efficiency. In this paper, a new type of profiled steel sheet and polyurethane sandwich slab (PSSPSS) was proposed. Through static load tests and numerical simulations, the flexural properties of the PSSPSS were studied, and the influence of individual geometric parameters on the flexural capacity of the structure was evaluated. The results of this analysis led to the derivation of the calculation formulas for the deflection and flexural bearing capacity of the PSSPSS. These results demonstrate that the bearing capacity and failure mode of the structure, as determined by test and simulation, are in perfect agreement. The sandwich slab’s failure is mainly demonstrated by an overabundance of deflection, with the peak being 1/42 of the span, and the channel steel at the middle span being distorted and snapped. The slab deflection calculation formula’s results, when compared to the test results, demonstrate a mere 2.1% error, thus confirming its accuracy. The slab thickness, profiled steel sheet thickness, polyurethane foam density, and slab span all contribute to higher bearing capacity and improved stiffness in the structure, yet the effect of the slab span is more evident. The slab span, however, has a more profound effect on stiffness. The flexural bearing capacity formula’s applicability is indicated by the maximum error being within 10%, as demonstrated by the comparison of the formula’s results with the FEA results for the sandwich slab with varying parameters.
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LOCAL BUCKLING (WRINKLING) OF PROFILED METAL-FACED INSULATING SANDWICH PANELS – A PARAMETRIC STUDY. The Hong Kong Institute of Steel Construction, August 2022. http://dx.doi.org/10.18057/icass2020.p.248.

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This study aims to investigate the effects of various parameters including the height of the profiling region, spacing of profiling ribs, length of the panel, thickness and modulus of the foam core, and thickness of the profiled face sheet, on the local buckling capacity of profiled metal faced insulating sandwich panels. A simplified finite element (FE) modeling approach that models the profiled face sheet as a folded plate structure resting on elastic foundation is adopted. This modeling approach was validated through comparison with tests results and 3D FE modeling of the entire sandwich structure in a previous study conducted by the authors. The two-parameter elastic foundation properties are determined using a modified nonlinear Vlasov foundation model. The results show that all the above-mentioned parameters play important roles in controlling the buckling capacity of the panel. However, the slenderness ratio of the panel is the most dominant parameter among all. Understanding the influence of each of the aforementioned parameters aids in the design process of such panels and provides insight into their local buckling response.
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NUMERICAL STUDY ON SHEAR BEHAVIOUR OF ENHANCED C-CHANNELS IN STEEL-UHPC-STEEL SANDWICH STRUCTURES. The Hong Kong Institute of Steel Construction, September 2021. http://dx.doi.org/10.18057/ijasc.2021.17.3.4.

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This paper firstly developed a three-dimensional (3D) finite element model (FEM) for enhanced C-channels (ECs) in steel-UHPC-steel sandwich structures (SUSSSs). The FEM was validated by 12 push-out tests on ECs with UHPC. With the validated FEM, this paper performed in-depth parametric studies on shear behaviours of ECs with ultra-high performance concrete (UHPC). These investigated parameters included bolt-hole gap (a), grade (M) and diameter (d) of bolt, core strength (fc), length of C-channel (Lc), and prestressing force ratio on bolt (ρ) in ECs. Under shear forces, the ECs in UHPC exhibited successive fractures of bolts and C-channels. Increasing the bolt-hole gap within 0-2 mm has no harm on the ultimate shear resistance, but greatly improves the slip capacity of ECs. Increasing grade and diameter of bolts improves the shear resistance and ductility of ECs through increasing the PB/PC (shear strength of bolt to that of C-channel) ratio. Increasing the core strength increased the shear resistance, but reduced the ductility of ECs due to the reduced PB/PC ratio. The ECs with Lc value of 50 mm offer the best ductility. Prestressing force acting on the bolts reduced the shear strength and ductility of ECs with UHPC. Analytical models were proposed to estimate the ultimate shear resistance and shear-slip behaviours of ECs with UHPC. The extensive validations of these models against 12 tests and 31 FEM analysis cases proved their reasonable evaluations on shear behaviours of ECs with UHPC.
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BUCKLING BEHAVIOUR OF THE STEEL PLATE IN STEEL – CONCRETE – STEEL SANDWICH COMPOSITE TOWER FOR WIND TURBINE. The Hong Kong Institute of Steel Construction, September 2022. http://dx.doi.org/10.18057/ijasc.2022.18.3.7.

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To solve the problem of collapses caused by local buckling of steel plates under compression in traditional steel towers, a novel steel-concrete-steel (SCS) sandwich composite tower for a wind turbine is proposed in this paper. To study the buckling behaviour of steel plates in SCS sandwich composite towers, six specimens were designed and tested under axial compression. The specimens were designed considering the key parameters of curvature radius, thickness of the steel plate, and the spacing-to-thickness ratio (the ratio of stud spacing to the thickness of steel plate). The failure modes, normalised average stress-strain curves and load-strain curves of the specimens were assessed, and the effects of the curvature radius and the spacing-to-thickness ratio of the steel plate were analysed. The experimental results showed that the buckling strength of the steel plate increased with a decrease in the ratio of the curvature radius to the thickness of the steel plate. The finite element (FE) model of the elastic buckling stress of the steel plate of the SCS sandwich composite tower was employed and validated against the test results. In parametric study, the effects of governing parameters including the curvature radius of the steel plate, thickness of the steel plate and spacing of the studs, on the effective length factors of the inner and outer steel plates were analysed. Subsequently, the design rules of the effective length factor of the inner and outer steel plates, and the design methods of spacing of studs to prevent local instability of the inner and outer steel plates before yielding were proposed.
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