Journal articles: 'SHEAR CORE'

1

Kwan, A. K. H. "Shear Lag in Shear/Core Walls." Journal of Structural Engineering 122, no. 9 (September 1996): 1097–104. http://dx.doi.org/10.1061/(asce)0733-9445(1996)122:9(1097).

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2

Deschapelles, Bernardo. "Discussion: Shear Lag in Shear/Core Walls." Journal of Structural Engineering 123, no. 11 (November 1997): 1552–54. http://dx.doi.org/10.1061/(asce)0733-9445(1997)123:11(1552).

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3

Joo, Hyo-Eun, Sun-Jin Han, Min-Kook Park, and Kang Su Kim. "Shear Tests of Deep Hollow Core Slabs Strengthened by Core-Filling." Applied Sciences 10, no. 5 (March 2, 2020): 1709. http://dx.doi.org/10.3390/app10051709.

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Prestressed hollow core slabs (PHCSs) have commonly been applied to long-span structures, due to their excellent flexural capacity and deflection control performance. However, in quite a few cases, the web-shear strength at member ends subjected to high shear forces is insufficient, because the web of the PHCS is very thin, making it difficult to place shear reinforcement, and the prestress is not fully effective in transfer length regions. Accordingly, a variety of shear strengthening methods have been proposed to improve the web-shear strength of PHCS ends. In this study, experimental research was conducted to investigate the shear resistance mechanism of PHCS strengthened by core-filling method, which has been most widely used in the construction field. The number of filled cores and the shear reinforcement ratio were set as the main test variables, and the patterns and angles of shear cracks that occurred in the PHCS units and filled cores, respectively, and the strain behavior of the shear reinforcement, were measured and analyzed in detail. This study also analyzed the test results based on the current design codes, and proposed a modified shear strength equation that can be applied to the core-filled PHCS.

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Cui, Shi Qi, Xu Wen Kong, Xin Wang, and Ming Liang Yang. "Experimental Study about Testing Masonry Shear Strength with Drilled Core Method." Applied Mechanics and Materials 166-169 (May 2012): 1241–44. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.1241.

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Key technology of testing masonry shear strength with core drilling method is that standard shear strength of masonry is determined from the shear strength of masonry core sample, while current code or specification has not provided the corresponding calculating formula. To investigate their relationship, a series of tests have been carried out. Existing test result analysis shows that standard shear strength of masonry and shear strength of masonry core sample are closely related. By means of testing data regression analysis, this work can establish the relationship formula between shear strength of single core sample and standard shear strength of masonry. This Technology can be suitable both to traditional masonry structure and to new wall materials masonry structure, especially to seismic appraiser and reinforcement calculation of masonry structure. This technology can support scientific basis to quality examination and assessment of new wall materials and analysis of engineering quality accident.

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5

HO, DUEN, and CHI HO LIU. "SHEAR-WALL AND SHEAR-CORE ASSEMBLIES WITH VARIABLE CROSS-SECTION." Proceedings of the Institution of Civil Engineers 81, no. 3 (September 1986): 433–46. http://dx.doi.org/10.1680/iicep.1986.549.

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6

Walter, Michael J. "A shear pathway to the core." Nature 403, no. 6772 (February 2000): 839–40. http://dx.doi.org/10.1038/35002698.

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7

Pavlova, S. A. "Analysis of contact interaction of polymer honeycomb core and CFRP base layers in sandwich-core constructions." VESTNIK of Samara University. Aerospace and Mechanical Engineering 20, no. 1 (April 20, 2021): 87–96. http://dx.doi.org/10.18287/2541-7533-2021-20-1-87-96.

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The article considers the challenge of studying the mechanical properties of composite sandwich constructions at the interface between the base layers and the lightweight core. The results of strength tests are presented for specimens of sandwich-core panels with coats made of high-strength carbon fiber-reinforced plastics (CFRP) and polymer honeycomb core considering various loading conditions. It is noted that a discrepancy in the values of shear stresses occurs in four-point bending and shear tests due to the complex stress-strain state of the specimens during bending. In order to interpret the experimental data, numerical analysis of the area of contact interaction between the coats and the filler of the sandwich-core composite structures is carried out. It is noted that in the presence of significant normal stresses in the adhesive coat the base layers separate from the core during shear tests and there is underestimation of the values of shear stresses by about 20%. Recommendations for the assignment of ultimate shear stresses for the use in practical design of sandwich-core composite constructions are put forward.

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8

HO, D., and CHI HO LIU. "CORRIGENDUM: SHEAR-WALL AND SHEAR-CORE ASSEMBLIES WITH VARIABLE CROSS- SECTION." Proceedings of the Institution of Civil Engineers 83, no. 1 (March 1987): 355. http://dx.doi.org/10.1680/iicep.1987.360.

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9

Wu, Xin Feng, Jian Ying Xu, Jing Xin Hao, Rui Liao, and Zhu Zhong. "Three-Point Bending Shear Stress of Wooden Sandwich Composite ." Materials Science Forum 852 (April 2016): 1337–41. http://dx.doi.org/10.4028/www.scientific.net/msf.852.1337.

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The effect of construction parameters and material type on bending shear stress and shear force was analyzed systematically. It is shown that maximum bending shear stress of sandwich construction is smaller than homogeneous single layer beam with same cross section if the skin has higher modulus than the core. Besides the effect of core or skin layer to shear force is almost identical for sandwich composite composed by different materials with same construction parameter. In addition, the shear force can be taken almost by the core of sandwich beam only if the ratio of core thickness to the whole is more than. Otherwise the resistance to shear force of skin layer should be considered to calculate the shear deformation. The results can provide basic theory for design optimization of sandwich construction.

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10

Nassif Sabr, Yousif, Dr Husain Khalaf Jarallah, and Dr Hassan Issa Abdul Kareem. "Improving the Shear Strength of Lightweight RC Thick Hollow Core Slab Made of Recycled Materials." International Journal of Engineering & Technology 7, no. 4.20 (November 28, 2018): 403. http://dx.doi.org/10.14419/ijet.v7i4.20.26143.

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This research paper focused on the experimental study about shear behavior of reinforced concrete thick hollow core slab. The reduction hollow length technique was used to resist the shear failure that occurred in the thick hollow core slab. The three hollows were used in tested slabs. The effect of reduction in the length of hollow in the shear region as well as the sides hollow was considered in the shear behavior of the tested hollow core slab. The recyclable material was used to a get of lightweight concrete, where the crushed clay brick was used as a coarse aggregate instead of the gravel. The test was done by applying two line load. The specimens were tested up to failure. The experimental results showed an increase in the shear strength up to 109.52% and an increase in the deflection up to 24% compared with the hollow core slab specimen that all hollow core is accessible. From the experimental result of this investigation can avoid the shear failure subsequently the load devolves from the shear region to the flexural region with change the mode of failure from shear failure to flexural-shear failure.

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11

Yang, Eomzi, Tae Sup Yun, Kwang Yeom Kim, Seong Woo Moon, and Yong-Seok Seo. "Estimation of the Structural and Geomechanical Anisotropy in Fault Gouges Using 3D Micro-Computed Tomography (μ-CT)." Sensors 20, no. 17 (August 20, 2020): 4706. http://dx.doi.org/10.3390/s20174706.

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Fault gouges play an important role in the shear deformation of fault zones, by causing weakness and frictional instability in structures. Previous studies have investigated the evolution of shear deformation of fault zones by observing experiments using remolded and synthetic gouge specimens at a micro-scale. However, how the spatial configuration of the rock constituents accounts for the 3D anisotropy of intact structures of fault gouges, particularly at the core-scale, is not well understood. We obtained 3D μ-CT images of directionally cored gouge specimens and performed statistical analysis to quantify the major orientation of the internal structures. Direct shear tests were conducted to investigate the relationship between the distribution of the internal structures and geomechanical behavior. The results show that the undisturbed fault gouge has a clear anisotropy parallel to the fault plane even at the core-scale. Moreover, the direct shear test results show that the frictional resistance of a fault gouge has anisotropy related to the fault plane. The simple, yet robust method proposed in this study confirms that the core-scale structural anisotropy is correlated to the anisotropic shear resistance.

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12

Becker, Roger J., and Donald R. Buettner. "Shear Tests of Extruded Hollow-Core Slabs." PCI Journal 30, no. 2 (March 1, 1985): 40–54. http://dx.doi.org/10.15554/pcij.03011985.40.54.

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13

Fung, T. C., and K. H. Tan. "Shear Stiffness for Z-Core Sandwich Panels." Journal of Structural Engineering 124, no. 7 (July 1998): 809–16. http://dx.doi.org/10.1061/(asce)0733-9445(1998)124:7(809).

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14

Deuss, Arwen, John H. Woodhouse, Hanneke Paulssen, and Jeannot Trampert. "The observation of inner core shear waves." Geophysical Journal International 142, no. 1 (July 2000): 67–73. http://dx.doi.org/10.1046/j.1365-246x.2000.00147.x.

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15

Al-Mosawi, S. S., and M. P. Saka. "Optimum design of single core shear walls." Computers & Structures 71, no. 2 (April 1999): 143–62. http://dx.doi.org/10.1016/s0045-7949(98)00239-9.

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16

Nordstrand, Tomas, Leif A. Carlsson, and Howard G. Allen. "Transverse shear stiffness of structural core sandwich." Composite Structures 27, no. 3 (1994): 317–29. http://dx.doi.org/10.1016/0263-8223(94)90091-4.

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17

Isaksson, P., A. Krusper, and P. A. Gradin. "Shear correction factors for corrugated core structures." Composite Structures 80, no. 1 (September 2007): 123–30. http://dx.doi.org/10.1016/j.compstruct.2006.04.066.

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18

Gond, AbhishekKumar, and S. K. Madan. "Nonlinear Static Analysis of Core Wall RCC Framed Buildings." Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, no. 1 (December 19, 2022): 1397–402. http://dx.doi.org/10.38208/acp.v1.669.

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RCC framed buildings mainly consists of shear walls and columns for resisting lateral force due to earthquakes. In most of the framed buildings shear walls are provided in the outer frames. In addition to shear walls provided in the outer frames, RCC lift -well (core wall) is also provided in the inner core of the buildings to accommodate lift. Core wall also acts as shear wall contributing to the lateral resistance to the buildings. In the present study, nonlinear static analysis is performed to study the behaviour of high rise RCC buildings, the buildings have a centralised lift core wall with a door opening and shear walls in outer frames. The flange of core wall is joined together at regular interval by floor and slabs and connecting beams to provide proper connection in between flange. This Residential G+14 RCC framed building is lying in seismic zone 4 and analysed as per guidelines of is 1893 (part 1) 2016 and ETABS 17.0.1. Responses namely lateral loads, story drift, base shear, story displacement and the formation of plastic hinges compared for two types of buildings, namely with core wall and without core wall to understand the effect of core wall against the lateral loads.

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19

Mostafa, A., and K. Shankar. "Finite Element Study on the Influence of Shear Key Diameter on the Shear Performance of Composite Sandwich Panel with PU Foam Core." Applied Mechanics and Materials 376 (August 2013): 103–7. http://dx.doi.org/10.4028/www.scientific.net/amm.376.103.

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The present study deals with the shear behavior of the composite sandwich panels comprised of Polyvinylchloride (PVC) and Polyurethane (PU) foam core sandwiched between Glass Fiber Reinforced Polymer (GFRP) skins using epoxy resin. Experiments have been carried out to characterize the mechanical response of the constituent materials under tension, compression and shear loading. In-plane shear tests for the sandwich panel reveal that the main failure mode is the delamination between the skin and the core rather than shearing the core itself since the skin-core interaction is the weakest link in such structure. The Finite Element Analysis (FEA) of the sandwich structure, based on the non-linear behavior of the foam core and skin-core cohesive interaction, shows that shear response and failure mode can be predicted with high accuracy.

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20

Mostafa, A., and K. Shankar. "In-Plane Shear Damage Prediction of Composite Sandwich Panel with Foam Core." Applied Mechanics and Materials 376 (August 2013): 69–73. http://dx.doi.org/10.4028/www.scientific.net/amm.376.69.

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The present study deals with the shear behavior of the composite sandwich panels comprised of Polyvinylchloride (PVC) and Polyurethane (PU) foam core sandwiched between Glass Fiber Reinforced Polymer (GFRP) skins using epoxy resin. Experiments have been carried out to characterize the mechanical response of the constituent materials under tension, compression and shear loading. In-plane shear tests for the sandwich panel reveal that the main failure mode is the delamination between the skin and the core rather than shearing the core itself since the skin-core interaction is the weakest link in such structure. The Finite Element Analysis (FEA) of the sandwich structure, based on the non-linear behavior of the foam core and skin-core cohesive interaction, shows that shear response and failure mode can be predicted with high accuracy.

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21

Kawashima, Masayuki. "Numerical Study of Horizontal Shear Instability Waves along Narrow Cold Frontal Rainbands." Journal of the Atmospheric Sciences 68, no. 4 (April 1, 2011): 878–903. http://dx.doi.org/10.1175/2010jas3599.1.

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Abstract The effects of variations in low-level ambient vertical shear and horizontal shear on the alongfront variability of narrow cold frontal rainbands (NCFRs) that propagate into neutral and slightly unstable environments are investigated through a series of idealized cloud-resolving simulations. In cases initialized with slightly unstable sounding and weak ambient cross-frontal vertical shears, core-gap structures of precipitation along NCFRs occur that are associated with wavelike disturbances that derive their kinetic energy mainly from the mean local vertical shear and buoyancy. However, over a wide range of environmental conditions, core-gap structures of precipitation occur because of the development of a horizontal shear instability (HSI) wave along the NCFRs. The growth rate and amplitude of the HSI wave decrease significantly as the vertical shear of the ambient cross-front wind is reduced. These decreases are a consequence of the enhancement of the low-level local vertical shear immediately behind the leading edge. The strong local vertical shear acts to damp the vorticity edge wave on the cold air side of the shear zone, thereby suppressing the growth of the HSI wave through the interaction of the two vorticity edge waves. It is also noted that the initial wavelength of the HSI wave increases markedly with increasing horizontal shear. The local vertical shear around the leading edge is shown to damp long HSI waves more strongly than short waves, and the horizontal shear dependency of the wavelength is explained by the decrease in the magnitude of the vertical shear relative to that of the horizontal shear.

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22

Lee, Yong-Jun, Hyeong-Gook Kim, Min-Jun Kim, Dong-Hwan Kim, and Kil-Hee Kim. "Shear Performance for Prestressed Concrete Hollow Core Slabs." Applied Sciences 10, no. 5 (February 29, 2020): 1636. http://dx.doi.org/10.3390/app10051636.

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This study evaluated the shear performance of prestressed concrete hollow core slabs (HCS), which are convenient to use as floor structures of flexible spaces. A total of 18 specimens, with cross-sectional height and presence of topping concrete as variables, were fabricated by extrusion. A four-point loading test was conducted using simply supported beams. The results showed that shear performance satisfied the requirements of ACI 318-19 regardless of cross-sectional height or presence of topping concrete. Through comparison with past studies, the web-shear strength of HCS was found to be influenced by compressive stress due to prestress at the centroid, compressive strength of concrete, and shear span-to-depth ratio.

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23

Challis, K. E., D. J. Hall, and D. B. Paul. "A Novel Method for Determining the Temperature Dependence of Shear Properties of Structural Foams." Cellular Polymers 5, no. 2 (March 1986): 91–101. http://dx.doi.org/10.1177/026248938600500202.

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A glass reinforced plastic( GRP) /foam sandwich has been chosen for the construction of the new Royal Australian Navy minehunter. Previous work has determined that elevated temperatures possible in Australian tropical conditions can have a deleterious effect on the foam core of such composites with subsequent reductions in composite structural strength. Full scale tests and underwater shock trials have shown that shear stress in the core is a prime cause of composite failure and hence reductions in core shear properties under the influence of temperature may affect the service performance of the vessel. Core shear properties in the temperature range 20–90°C have been monitored using a new torsional shear instrument which for thick foam materials offers substantial advantages in comparison with standard plate shear methods. Results for a number of commercial closed cell modified PVC foams are presented and indicate that at 90° C the decline in shear strength and shear modulus is 30–50%. Comparisons between torsional and plate shear procedures were also undertaken and a rationalisation for observed differences is proposed

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24

Tkalčić, Hrvoje, and Thanh-Son Phạm. "Shear properties of Earth’s inner core constrained by a detection ofJwaves in global correlation wavefield." Science 362, no. 6412 (October 18, 2018): 329–32. http://dx.doi.org/10.1126/science.aau7649.

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SeismicJwaves, shear waves that traverse Earth’s inner core, provide direct constraints on the inner core’s solidity and shear properties. However, these waves have been elusive in the direct seismic wavefield because of their small amplitudes. We devised a new method to detectJwaves in the earthquake coda correlation wavefield. They manifest through the similarity with other compressional core-sensitive signals. The inner core is solid, but relatively soft, with shear-wave speeds and shear moduli of 3.42 ± 0.02 kilometers per second and 149.0 ± 1.6 gigapascals (GPa) near the inner core boundary and 3.58 ± 0.02 kilometers per second and 167.4 ± 1.6 GPa in Earth’s center. The values are 2.5% lower than the widely used Preliminary Earth Reference Model. This provides new constraints on the dynamical interpretation of Earth’s inner core.

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Mario M. Attard. "Global Buckling Experiments on Sandwich Columns with Soft Shear Cores." Electronic Journal of Structural Engineering 11 (January 1, 2011): 21–31. http://dx.doi.org/10.56748/ejse.11140.

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Several failure modes for sandwich columns under compression are said to be possible with shear crimping or shear buckling suggested for short columns with soft shear cores. The buckling formulas and theoretical assumptions of Engesser and Haringx for isotropic columns and soft shear core sandwich columns are reviewed. An important distinction is made between the isotropic column buckling formula attributed to Haringx and the theoretical assumptions underpinning his approach. It is shown that the theoretical approaches of Haringx and Engesser yield the same basic buckling equation for soft shear core sandwich columns when the thickness is very small in comparison to the core thickness, and the shear in the face sheets, the axial force in the core and the bending within the face sheets are ignored. To determine whether shear crimping (shear buckling) is a member or localised type of buckle, tests on low slenderness - short sandwich columns identified as possibly exhibiting shear crimping, were preformed. The test specimens were constructed from 10 mm thick Divinycell H45, H80, H100 and H200 foam for the core and 1 mm face sheets made of Aluminum 2024-T3. The lengths of the columns varied from 20 to 500 mm. The columns were endclamped according to ASTM C 364-99 [1] and placed in a servo-controlled compression testing machine. The width of the specimens was 100 mm and two specimens at each length were tested. The adhesive chosen was a toughened epoxy, trade name “Devcon Epoxy Plus". Measurements of the mid-span lateral displacement were used in a Southwell type plot to determine the elastic global buckling load. The shear modulus of the core was determined from three point bending tests according to ASTM-C-393 [2]. Some of the very short specimens failed with buckling of the face sheet within the clamped region. None of the tests exhibited shear crimpling or shear buckling modes and the global buckling loads for very short columns were much higher than the shear buckling limit of Engesser. Wrinkling failure was not considered.

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26

Kooistra, Gregory W., Vikram Deshpande, and Haydn N. G. Wadley. "Hierarchical Corrugated Core Sandwich Panel Concepts." Journal of Applied Mechanics 74, no. 2 (September 20, 2005): 259–68. http://dx.doi.org/10.1115/1.2198243.

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The transverse compression and shear collapse mechanisms of a second order, hierarchical corrugated truss structure have been analyzed. The two competing collapse modes of a first order corrugated truss are elastic buckling or plastic yielding of the truss members. In second order trusses, elastic buckling and yielding of the larger and smaller struts, shear buckling of the larger struts, and wrinkling of the face sheets of the larger struts have been identified as the six competing modes of failure. Analytical expressions for the compressive and shear collapse strengths in each of these modes are derived and used to construct collapse mechanism maps for second order trusses. The maps are useful for selecting the geometries of second order trusses that maximize the collapse strength for a given mass. The optimization reveals that second order trusses made from structural alloys have significantly higher compressive and shear collapse strengths than their equivalent mass first order counterparts for relative densities less than about 5%. A simple sheet metal folding and dip brazing method of fabrication has been used to manufacture a prototype second order truss with a relative density of about 2%. The experimental investigation confirmed the analytical strength predictions of the second order truss, and demonstrate that its strength is about ten times greater than that of a first order truss of the same relative density.

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27

Nagarajan, Kaviya, and Dr R. Thenmozhi. "Study of Parameters Affecting Web-Shear Capacity of Multiple Deep Hollow Core Slab System through Finite Element Analysis." International Journal for Research in Applied Science and Engineering Technology 11, no. 8 (August 31, 2023): 1440–46. http://dx.doi.org/10.22214/ijraset.2023.55363.

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Abstract: Precast industry is gaining popularity in construction industry due to its faster erection and less labour requirement as it manufactured in factories. In this paper, an overview of hollow core, how they are cast, advantages and disadvantages of hollow core slab are described. Generally, it is known that the hollow core slabs are critical in web shear. Parameters which potentially affect the web shear behaviour are explained. This paper reviews the previous research works published on web shear capacity of hollow core slabs studied experimentally, numerically and parametrically

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Cao, Lyra, Marc H. Pinsonneault, and Jennifer L. van Saders. "Core-envelope Decoupling Drives Radial Shear Dynamos in Cool Stars." Astrophysical Journal Letters 951, no. 2 (July 1, 2023): L49. http://dx.doi.org/10.3847/2041-8213/acd780.

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Abstract Differential rotation is thought to be responsible for the dynamo process in stars like our Sun, driving magnetic activity and starspots. We report that starspot measurements in the Praesepe open cluster are strongly enhanced only for stars that depart from standard models of rotational evolution. A decoupling of the spin-down history between the core and envelope explains both the activity and rotation anomalies: surface rotational evolution is stalled by interior angular momentum redistribution, and the resultant radial shears enhance starspot activity. These anomalies provide evidence for an evolving front of shear-enhanced activity affecting the magnetic and rotational evolution of cool stars and the high-energy environments of their planetary companions for hundreds of millions to billions of years on the main sequence.

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29

Irie, Masao, Yukinori Maruo, Goro Nishigawa, Kumiko Yoshihara, and Takuya Matsumoto. "Flexural Strength of Resin Core Build-Up Materials: Correlation to Root Dentin Shear Bond Strength and Pull-Out Force." Polymers 12, no. 12 (December 9, 2020): 2947. http://dx.doi.org/10.3390/polym12122947.

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The aims of this study were to investigate the effects of root dentin shear bond strength and pull-out force of resin core build-up materials on flexural strength immediately after setting, after one-day water storage, and after 20,000 thermocycles. Eight core build-up and three luting materials were investigated, using 10 specimens (n = 10) per subgroup. At three time periods—immediately after setting, after one-day water storage, and after 20,000 thermocycles, shear bond strengths to root dentin and pull-out forces were measured. Flexural strengths were measured using a 3-point bending test. For all core build-up and luting materials, the mean data of flexural strength, shear bond strength and pull-out force were the lowest immediately after setting. After one-day storage, almost all the materials yielded their highest results. A weak, but statistically significant, correlation was found between flexural strength and shear bond strength (r = 0.508, p = 0.0026, n = 33). As the pull-out force increased, the flexural strength of core build-up materials also increased (r = 0.398, p = 0.0218, n = 33). Multiple linear regression analyses were conducted using these three independent factors of flexural strength, pull-out force and root dentin shear bond strength, which showed this relationship: Flexural strength = 3.264 × Shear bond strength + 1.533 × Pull out force + 10.870, p = 0.002). For all the 11 core build-up and luting materials investigated immediately after setting, after one-day storage and after 20,000 thermocycles, their shear bond strengths to root dentin and pull-out forces were correlated to the flexural strength in core build-up materials. It was concluded that the flexural strength results of the core build-up material be used in research and quality control for the predictor of the shear bond strength to the root dentin and the retentive force of the post.

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30

Zhuo, Renyan, Xinfang Ma, Shicheng Zhang, Junxiu Ma, Yuankai Xiang, and Haoran Sun. "Classification and Assessment of Core Fractures in a Post-Fracturing Conglomerate Reservoir Using the AHP–FCE Method." Energies 16, no. 1 (December 29, 2022): 418. http://dx.doi.org/10.3390/en16010418.

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To characterize the hydraulic fracture network of a conglomerate reservoir, a slant core well was drilled aimed to obtain direct information regarding hydraulic fractures through slant core at the conglomerate hydraulic fracturing test site (CHFTS). Core fracture classification was the fundamental issue of the project. In this study, three grade classifications for core fractures were proposed. Comprehensive classification of core fractures was carried out using the analytic hierarchy process (AHP)–fuzzy comprehensive evaluation (FCE) method. Finally, the fracture classification results were validated against numerical simulation. The grade-1 fracture classification included hydraulic fractures, drilling-induced fractures and core cutting-induced fractures. A total of 214 hydraulic fractures were observed. For the grade-2 classification, the hydraulic fractures were divided into 47 tensile fractures and 167 shear fractures. For the grade-3 classification, the shear fractures were subdivided into 45 tensile-shear fractures and 122 compression-shear fractures. Based on the numerical verification of the core fracture classifications, the dataset acquired was applied to analyze the spatial distribution of tensile and shear fractures. Results showed that the tensile fractures were mainly in the near-wellbore area with lateral distances of less than 20 m–25 m from the wellbore. The shear fractures were mainly in the far-wellbore area with lateral distances of 20 m–30 m from the wellbore. These results provide a basis for understanding the fracture types, density, and failure mechanisms of post-fracturing conglomerate reservoir.

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31

Toubia, Elias A., Sadra Emami, and Donald Klosterman. "Degradation mechanisms of balsa wood and PVC foam sandwich core composites due to freeze/thaw exposure in saline solution." Journal of Sandwich Structures & Materials 21, no. 3 (April 28, 2017): 990–1008. http://dx.doi.org/10.1177/1099636217706895.

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Structural engineers commonly use balsa wood and PVC foam as core materials for sandwich composite structures. These structures are frequently exposed to thermal cycling in sea water. The long-term performance and damage mechanism of these composite sandwich structures under such environmental conditions are still unclear. To simulate these effects, sandwich panels using balsa wood (SB100) and foam core (Airex C70.55) with fiber glass/vinyl ester face sheets were exposed to 100 days of freeze/thaw exposure (−20℃ to 20℃). The freezing and thawing occurred in presence of a saline solution. A total of 150 samples were tested for core shear, core compression, and peel tests. Results confirmed that exposure reduced the balsa wood core shear strength by 14%, compression strength by 36%, and compression modulus by 33%. Interestingly, the PVC foam core shear modulus increased by 25% after exposure, whereas the compression modulus reduced by 12%. Simulated lifetime core shear fatigue curves were developed and evaluated. Additional testing techniques such as scanning electron microscopy, optical microscopy, dynamical mechanical analysis, and X-ray computed tomography were used to rationalize the static and fatigue behavior of the core materials.

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32

Kwan, A. K. H. "Closure to “Shear Lag in Shear/Core Walls” by A. K. H. Kwan." Journal of Structural Engineering 123, no. 11 (November 1997): 1553. http://dx.doi.org/10.1061/(asce)0733-9445(1997)123:11(1553).

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33

Vuran, Eren. "Shear migration and dynamic shear amplification effects on seismic response of core walls." Bulletin of Earthquake Engineering 16, no. 10 (May 10, 2018): 5003–15. http://dx.doi.org/10.1007/s10518-018-0362-4.

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34

Azodi, Maryam, Mehdi Banazadeh, and Amir Mahmoudi. "Seismic performance assessment of high-rise steel moment frame building with Reinforced Concrete (RC) core wall based on nonlinear time history analysis." Research, Society and Development 11, no. 4 (March 20, 2022): e35711427464. http://dx.doi.org/10.33448/rsd-v11i4.27464.

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This paper focuses on seismic responses of a 30-story high-rise building with a dual lateral system of Reinforced Concrete (RC) core shear wall and steel moment frame. To assess the seismic performance of the building, a nonlinear finite element model is built by using the OpenSees software. This three-dimensional model is created by using the fiber-beams for members and multi-layer shell elements for RC core walls. The numerical simulation has been examined under the thirteen sets of strong ground motion records which are scaled with the design and maximum seismic levels, Design-Basis Earthquake (DBE) and Maximum Considered Earthquake (MCE) level hazards respectively. In consequence, the desirable performance of high-rise steel moment frame building with RC shear core consisting of coupling beams and rectangular shear walls is shown. The outcome of nonlinear time history analyses reports the acceptable seismic performance of tall buildings designed. Results showed that maximum inter-story drift is significantly lower than allowable drift. Also, the RC core wall absorbed almost two-third of the total shear forces from the base level to one-third of height. However, the shear values of the core wall were significantly reduced by increasing the height while the shear values of the steel moment frame stayed constant.

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Wu, Tao, Xi Liu, Guo Hua Xing, and Bo Quan Liu. "Shear Behavior of Interior Joints with Different Depth Beams in RC Frame Structures." Advanced Materials Research 217-218 (March 2011): 1504–9. http://dx.doi.org/10.4028/www.scientific.net/amr.217-218.1504.

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Six specimens of interior joints with different depth beams were tested under reversed cyclic loading. The failure characteristics and shear force versus shear angle skeleton curves of interior joints are analyzed. Based on the experimental study, an analytical model for equivalent joint core of abnormal joint under the combined action of axial load and shear is established, and the shear stress versus shear angle curves of equivalent joint core of tested specimens was calculated by using modified compression field theory (MCFT).Test results indicated that the first crack appeared in the minor core (determined by the low beam and the top column), and the final failure appeared in the large core (determined by the high beam and the bottom column). The critical crack load was quite nearly with the ultimate load of abnormal joints, and seismic behavior of beam-column joint sub-assemblage was poorer than that of ordinary joints. Good agreement between experimental results and prediction results is achieved.

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Sadik, Tarik, Caroline Pillon, Christian Carrot, José A. Reglero Ruiz, Michel Vincent, and Noëlle Billon. "Polypropylene structural foams: Measurements of the core, skin, and overall mechanical properties with evaluation of predictive models." Journal of Cellular Plastics 53, no. 1 (July 28, 2016): 25–44. http://dx.doi.org/10.1177/0021955x16633643.

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Relationships for the prediction of various linear mechanical properties of polymeric sandwich foams obtained in injection processes were studied in comparison with shear, tensile, and flexural tests. The samples were obtained by a core-back foam injection molding process that enables one to obtain sandwich materials with dense skins and a foamed core as revealed by the morphological analysis. Tensile, shear, and flexural moduli were investigated for the skin, the core, and the overall foamed structure. In addition, the Poisson’s ratio of the skin was also determined. The core properties were specifically analyzed by machining the samples and removing the skins. Tensile and shear properties of the core can be well described by the Moore equation. The tensile modulus can be calculated by a linear mixing rule with the moduli of the skin and of the core in relation to the thickness of the layers. Shear and flexural moduli are described by a linear mixing rule on the rigidity in agreement with the mechanics of beams. Tensile modulus, out-of-plane shear modulus, and flexural modulus can finally be predicted by the knowledge of only very few data, namely the tensile modulus and Poisson’s ratio of the matrix, the void fraction, and thickness of the core. The equations were proved to be physically meaningful and consistent with each other.

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Jacques, Eric, and Jon Makar. "Behaviour of structural insulated panels (SIPs) subjected to short-term out-of-plane transverse loads." Canadian Journal of Civil Engineering 46, no. 9 (September 2019): 858–69. http://dx.doi.org/10.1139/cjce-2018-0015.

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Structural insulated panels (SIPs) are a panelized building system composed of external oriented strand board (OSB) wood sheets bonded to a lightweight boardstock or pour-in-place foam core. This paper describes an investigation on the structural behaviour of OSB-faced SIPs subject to short-term out-of-plane transverse loading. A total of 35 panels with varying types of foam core, thickness and other construction details were subjected to partially distributed uniform loading. The results showed that the ultimate shear resistance of SIPs is proportional to the mechanical properties of the core, and inversely proportional to the thickness of the core. The observed relationship between core shear stress at failure and core thickness was used to calibrate a reliability-based design expression to predict the shear strength of full-size panels based on properties obtained from small-scale foam material tests. Sandwich panel theory can accurately predict the initial stiffness of SIPs when behaviour remains in the linear range. Finally, recommendations regarding panel design and construction are made to improve the shear behaviour of SIPs.

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Banerjee, S., M. Battley, and D. Bhattacharyya. "Shear Strength Optimization of Reinforced Honeycomb Core Materials." Mechanics of Advanced Materials and Structures 17, no. 7 (October 19, 2010): 542–52. http://dx.doi.org/10.1080/15376490903398714.

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Levartovsky, Shifra, Gary R. Goldstein, and Maria Georgescu. "Shear bond strength of several new core materials." Journal of Prosthetic Dentistry 75, no. 2 (February 1996): 154–58. http://dx.doi.org/10.1016/s0022-3913(96)90092-x.

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Chen, Chin-Jen, Wenchin Liu, and Shue-Ming Chern. "Torsional analysis of shear core structures with openings." Computers & Structures 41, no. 1 (January 1991): 99–104. http://dx.doi.org/10.1016/0045-7949(91)90160-n.

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Pisanty, A. "The shear strength of extruded hollow-core slabs." Materials and Structures 25, no. 4 (May 1992): 224–30. http://dx.doi.org/10.1007/bf02473067.

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Rejab, MRM, K. Ushijima, and WJ Cantwell. "The shear response of lightweight corrugated core structures." Journal of Composite Materials 48, no. 30 (December 10, 2013): 3785–98. http://dx.doi.org/10.1177/0021998313514086.

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Schacht, Gregor, Steffen Marx, and Guido Bolle. "Shear load testing of damaged hollow-core slabs." Structural Concrete 18, no. 4 (February 20, 2017): 607–17. http://dx.doi.org/10.1002/suco.201600082.

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Mausbach, P., and H. O. May. "Shear Viscosity of the Gaussian Core Model Fluid." PAMM 6, no. 1 (December 2006): 571–72. http://dx.doi.org/10.1002/pamm.200610266.

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Gdoutos, E. E., and M. S. Konsta-Gdoutos. "Load and Geometry Effect on Failure Mode Initiation of Composite Sandwich Beams." Applied Mechanics and Materials 3-4 (August 2006): 173–78. http://dx.doi.org/10.4028/www.scientific.net/amm.3-4.173.

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Facing compressive failure, facing wrinkling and core shear failure are the most commonly encountered failure modes in sandwich beams with facings made of composite materials. The occurrence and sequence of these failure modes depends on the geometrical dimensions, the form of loading and type of support of the beam. In this paper the above three failure modes in sandwich beams with facings made of carbon/epoxy composites and cores made of aluminum honeycomb and two types of foam have been investigated. Two types of beams, the simply supported and the cantilever have been considered. Loading included concentrated and uniform. It was found that in beams with foam core facing wrinkling and core shear failure occur, whereas in beams with honeycomb core facing compressive failure and core shear crimping take place. Results were obtained for the dependence of failure mode on the geometry of the beam and the type of loading. The critical beam spans for failure mode transition from core shear to wrinkling failure were established. It was found that initiation of a particular failure mode depends on the properties of the facing and core materials, the geometrical configuration and loading of composite sandwich beams.

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Kheirikhah, Mohammad Mahdi, and Seyyed Mohammad Reza Khalili. "Bending Analysis of Composite Sandwich Plates with Flexible Core Using 3D Finite Element Method." Applied Mechanics and Materials 110-116 (October 2011): 1229–36. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.1229.

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Sandwich plates have been extensively used in many engineering applications such as automotive and aerospace. In the present paper, an accurate finite element model is presented for bending analysis of soft-core rectangular sandwich plates. The sandwich plate is composed of three layers: top and bottom skins and core layer. The core is assumed as a soft orthotropic material and skins are assumed generally unequal laminated composites. Finite element model of the problem has been constructed in the ANSYS 11.0 standard code area. Continuity conditions of transverse shear stresses at the interfaces are satisfied as well as the conditions of zero transverse shear stresses on the upper and lower surfaces of plate. Also transverse flexibility and transverse normal strain and stress of core are considered. The effect of geometrical parameters of the sandwich plate are studied. Comparison of the present results with those of plate theories confirms the accuracy of the proposed model.

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Omachi, Ayumi, Kuniharu Ushijima, Dai-Heng Chen, and Wesley J. Cantwell. "Prediction of failure modes and peak loads in lattice sandwich panels under three-point loading." Journal of Sandwich Structures & Materials 22, no. 5 (July 24, 2018): 1635–59. http://dx.doi.org/10.1177/1099636218789605.

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In this study, the failure behaviour of lattice sandwich panels under three-point loading has been studied using a nonlinear finite element analysis. The failure mechanisms of lattice-cored sandwich panels can be classified in three modes; facesheet yielding, facesheet wrinkling and core shear. When the panel fails due to facesheet yielding or core shear, the evaluation of the strength of the lattice-cored panel can be undertaken in the same manner as that of a foam-cored panel. In contrast, when wrinkle-like deformation occurs in the facesheets, the failure load can be estimated from the buckling stress of the facesheet. The failure mode map for the lattice-cored panel with the coordinate system tf / l and [Formula: see text] can be described by the analytical equations that predict the three failure modes. The failure mode map highlights the dominant failure modes for the lattice-cored sandwich panel based on the key design parameters tf / l and [Formula: see text].

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Tuo, Wanyong, Jinxiang Chen, Mengye Xu, Zhijie Zhang, and Zhensheng Guo. "Shear mechanical properties of the core structure of biomimetic fully integrated honeycomb plates." Journal of Sandwich Structures & Materials 22, no. 4 (June 18, 2018): 1184–98. http://dx.doi.org/10.1177/1099636218782728.

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In the present study, the shear failure mode and mechanical properties of the core structure of biomimetic fully integrated honeycomb plates with sealing edges were investigated experimentally and through the finite element method. The findings are as follows: (1) the failure mode of the sealing edges and honeycomb walls perpendicular to the shear direction is mainly debonding between the fiber and matrix, whereas fiber breakage, debonding between the fiber and matrix and exfoliation of the resin matrix occur in the sealing edges parallel to the shear direction. Meanwhile, the reasonableness and feasibility of the double shear testing apparatus designed in this study were verified, thus confirming the results of research are reliable and valid. (2) Shear failure of the core structure of fully integrated honeycomb plates is mainly fiber debonding appearing in the middle surface of the core structure, which is a failure of the material interface. Stripping failure in the joint interface of the core layer and upper and lower plates does not occur, which indicates that the biological structure possesses excellent integral mechanical properties. (3) The sealing edges parallel to the shear direction and the honeycomb walls that are oriented 30 degrees to the shear direction are the first to fail, followed by the sealing edges and honeycomb walls perpendicular to the shear direction, which is consistent with the microscopic failure phenomenon observed in both directions. To prevent failure at the material interface, the fully integrated honeycomb plates manufactured in this experiment require further improvements. Thus, countermeasures are proposed, such as pre-treating the fiber surface. These findings will specify future research directions to perfect fully integrated honeycomb plates and improve the shear mechanical properties of core structures.

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Seno, Aldyandra Hami, Eko Koswara, Hendri Syamsudin, and Djarot Widagdo. "Analysis of Bending Loads on Bamboo-Balsa and Bamboo-Polypropylene Honeycomb Composite Sandwiches." Advanced Materials Research 1125 (October 2015): 94–99. http://dx.doi.org/10.4028/www.scientific.net/amr.1125.94.

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This research was done to evaluate the bending behavior (load-deflection curve and failuremode) of sandwich structures using Tali Bamboo strips as sandwich skin material. Bending tests wereconducted on sandwich specimens with end grain balsa (3-point bending) and polypropylene (PP)honeycomb cores (4-point bending) to evaluate their bending behavior. From the test results,analytical and numerical models were developed to simulate the observed bending behavior. Themodels are able to simulate the pre-failure bending behavior and failure modes (core shear failure) ofthe specimens. It is also shown that for thin (length/thickness > 20) sandwiches the models are moreaccurate since shear effects are less prominent. With the obtained models a predictive comparison isdone between the PP and balsa cored specimens since the testing configuration for each type wasdifferent. The analysis results show that balsa cored specimens are able to withstand higher transversebending loads due to the higher shear strength of the balsa core. These prediction results are to beproven by specimen testing which is the subject of future research.

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Park, DongSoon, and Tadahiro Kishida. "Shear modulus reduction and damping ratio curves for earth core materials of dams." Canadian Geotechnical Journal 56, no. 1 (January 2019): 14–22. http://dx.doi.org/10.1139/cgj-2017-0529.

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It is essential to obtain shear modulus reduction and damping ratio curves to perform dynamic analyses of earth-cored embankment dams. Many studies have been performed for dynamic properties of clayey soils, but they have been limited for earth core materials of dams. This study conducted resonant column tests to obtain shear modulus reduction (G/Gmax) and damping ratio (D) curves for 31 specimens (17 undisturbed and 14 remolded specimens) from 13 earth-cored embankment dams. Empirical G/Gmax and D curves are proposed for dynamic properties of clayey earth core materials. Fitting curves are provided by using the functional forms of the Ramberg–Osgood and Darendeli models. The observation shows that the undisturbed earth cores yield relatively higher G/Gmax and lower D curves than the remolded cores. G/Gmax curves of compacted earth cores are relatively higher than those of Vucetic and Dobry curves for a similar level of plasticity index. Uncertainty and bias are calculated by performing residual analysis, which shows that there is no clear bias in predicting G/Gmax and the uncertainties between undisturbed earth core materials and natural deposits are at a similar level. A proposed empirical relationship of G/Gmax and D curves for earth core materials can be utilized for dynamic analyses of embankment dams for cases where there is insufficient in situ data.

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Journal articles on the topic 'SHEAR CORE'

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