Artykuły w czasopismach: „Smooth bars”

1

VOLINO, RALPH J., MICHAEL P. SCHULTZ i KAREN A. FLACK. "Turbulence structure in boundary layers over periodic two- and three-dimensional roughness". Journal of Fluid Mechanics 676 (15.03.2011): 172–90. http://dx.doi.org/10.1017/s0022112011000383.

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Measurements are presented from turbulent boundary layers over periodic two- and three-dimensional roughness. Cases with transverse rows of staggered cubes and cases with solid square transverse bars of two sizes were considered. Previous results by Volino, Schultz & Flack (J. Fluid Mech. vol. 635, 2009, p. 75) showed outer-layer similarity between cases with three-dimensional roughness and smooth walls, and deviations from similarity in cases with large two-dimensional transverse bars. The present results show that differences also occur with small two-dimensional bars and to a lesser extent when the bars are replaced with rows of staggered cubes. Differences are most apparent in correlations of turbulence quantities, which are of larger spatial extent for the rough-wall cases. The results with the staggered cubes indicate that part of the periodic roughness effect is caused by the repeated disturbance and recovery of the boundary layer as it encounters a row of roughness followed by a smooth surface. A larger effect, however, is due to the blockage caused by the two-dimensional transverse bars, which extend across the entire width of the boundary layer. The small two-dimensional bars have a larger effect than the staggered cubes, in spite of the bar height being only 11 viscous units and 1/7 of the cube height. The effect of the small bars extends well into the outer flow, indicating that effects observed previously with larger bars were not due only to a thickening of the roughness sublayer. The observed differences between the rough- and smooth-wall results are believed to be caused by large-scale attached eddies which extend from the roughness elements to the edge of the boundary layer.

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Hayashi, Taro. "Orders of automorphisms of smooth plane curves for the automorphism groups to be cyclic". Arabian Journal of Mathematics 10, nr 2 (18.05.2021): 409–22. http://dx.doi.org/10.1007/s40065-021-00321-5.

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AbstractFor a fixed integer $$d\ge 4$$ d ≥ 4 , the list of groups that appear as automorphism groups of smooth plane curves whose degree is d is unknown, except for $$d=4$$ d = 4 or 5. Harui showed a certain characteristic about structures of automorphism groups of smooth plane curves. Badr and Bars began to study for certain orders of automorphisms and try to obtain exact structures of automorphism groups of smooth plane curves. In this paper, based on the result of T. Harui, we extend Badr–Bars study for different and new cases, mainly for the cases of cyclic groups that appear as automorphism groups.

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3

Stone, L. S., J. Lorenceau i B. R. Beutter. "Smooth Pursuit of a Partially Occluded Object". Perception 25, nr 1_suppl (sierpień 1996): 150. http://dx.doi.org/10.1068/v96l0201.

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There has long been qualitative evidence that humans can pursue an object defined only by the motion of its parts (eg Steinbach, 1976 Vision Research16 1371 – 1375). We explored this quantitatively using an occluded diamond stimulus (Lorenceau and Shiffrar, 1992 Vision Research32 263 – 275). Four subjects (one naive) tracked a line-figure diamond moving along an elliptical path (0.9 Hz) either clockwise (CW) or counterclockwise (CCW) behind either an X-shaped aperture (CROSS) or two vertical rectangular apertures (BARS), which obscured the corners. Although the stimulus consisted of only four line segments (108 cd m−2), moving within a visible aperture (0.2 cd m−2) behind a foreground (38 cd m−2), it is largely perceived as a coherently moving diamond. The intersaccadic portions of eye-position traces were fitted with sinusoids. All subjects tracked object motion with considerable temporal accuracy. The mean phase lag was 5°/6° (CROSS/BARS) and the mean relative phase between the horizontal and vertical components was +95°/+92° (CW) and −85°/−75° (CCW), which is close to perfect. Furthermore, a \chi2 analysis showed that 56% of BARS trials were consistent with tracking the correct elliptical shape ( p<0.05), although segment motion was purely vertical. These data disprove the main tenet of most models of pursuit: that it is a system that seeks to minimise retinal image motion through negative feedback. Rather, the main drive must be a visual signal which has already integrated spatiotemporal retinal information into an object-motion signal.

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4

Silling, S. A. "Two-Dimensional Effects in the Necking of Elastic Bars". Journal of Applied Mechanics 55, nr 3 (1.09.1988): 530–35. http://dx.doi.org/10.1115/1.3125825.

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Numerical solutions for incompressible hyperelastic bars undergoing smooth necking in plane strain show complex phenomena in which two-dimensional effects are inherently important. In long bars, the two-dimensional effects are confined to a transition zone between the necked and non-necked phases. In spite of the two-dimensional effects, the nominal stress in necked long bars is close to the Maxwell stress under certain conditions. For very long bars there are necked equilibrium deformations in which the overall stretch is less than that of the maximum in the constitutive relation.

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5

Leonardi, S., P. Orlandi, L. Djenidi i R. A. Antonia. "Heat transfer in a turbulent channel flow with square bars or circular rods on one wall". Journal of Fluid Mechanics 776 (13.07.2015): 512–30. http://dx.doi.org/10.1017/jfm.2015.344.

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Direct numerical simulations (DNS) are carried out to study the passive heat transport in a turbulent channel flow with either square bars or circular rods on one wall. Several values of the pitch (${\it\lambda}$) to height ($k$) ratio and two Reynolds numbers are considered. The roughness increases the heat transfer by inducing ejections at the leading edge of the roughness elements. The amounts of heat transfer and mixing depend on the separation between the roughness elements, an increase in heat transfer accompanying an increase in drag. The ratio of non-dimensional heat flux to the non-dimensional wall shear stress is higher for circular rods than square bars irrespectively of the pitch to height ratio. The turbulent heat flux varies within the cavities and is larger near the roughness elements. Both momentum and thermal eddy diffusivities increase relative to the smooth wall. For square cavities (${\it\lambda}/k=2$) the turbulent Prandtl number is smaller than for a smooth channel near the wall. As ${\it\lambda}/k$ increases, the turbulent Prandtl number increases up to a maximum of 2.5 at the crests plane of the square bars (${\it\lambda}/k=7.5$). With increasing distance from the wall, the differences with respect to the smooth wall vanish and at three roughness heights above the crests plane, the turbulent Prandtl number is essentially the same for smooth and rough walls.

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6

Nord, K. J., i T. J. Chung. "Fracture and surface flaws in smooth and threaded round bars". International Journal of Fracture 30, nr 1 (styczeń 1986): 47–55. http://dx.doi.org/10.1007/bf00034578.

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Nemes, J. A., i J. Eftis. "Constitutive modeling of the dynamic fracture of smooth tensile bars". International Journal of Plasticity 9, nr 2 (styczeń 1993): 243–70. http://dx.doi.org/10.1016/0749-6419(93)90031-k.

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Arani, Kamyar Karbasi, Mohammad S. Marefat, Marco Di Ludovico, Andrea Prota i Gaetano Manfredi. "Hysteretic cyclic response of concrete columns reinforced with smooth bars". Bulletin of Earthquake Engineering 11, nr 6 (5.06.2013): 2033–53. http://dx.doi.org/10.1007/s10518-013-9469-9.

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Rimal, Hariram, Piyush Pradhan, Dipendra Gautam i Rajesh Rupakhety. "Seismic Fragility of Aging Elevated Water Tank with Smooth Bars Considering Soil Structure Interaction". Buildings 13, nr 1 (20.12.2022): 4. http://dx.doi.org/10.3390/buildings13010004.

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The functionality of elevated water tanks is pivotal to assure after an earthquake as water supply is expected to be uninterrupted. Although elevated water tanks with deformed bars are widely studied, limited works exist for water tanks with smooth bars, although such tanks comprise a considerable fraction, even in the high seismic regions. To quantify the seismic vulnerability of aging elevated water tanks with smooth bars, we created analytical fragility functions for full, half, and empty reservoir conditions, considering fluid–structure and soil–structure interactions. The sum of findings reflects that soil flexibility and the amount of water present in the tank have a significant effect on overall seismic fragility, especially at higher damage states. The tanks are found to be most vulnerable when they are fully filled with water. The effect of soil flexibility is more pronounced at higher damage states. The difference between the fragility of flexible base and fixed base structures is found to increase with increasing ground motion intensity and it is the highest for the empty tank condition.

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10

Caruso, Claudia, Rita Bento, Romain Sousa i António A. Correia. "Modelling strain penetration effects in RC walls with smooth steel bars". Magazine of Concrete Research 71, nr 17 (wrzesień 2019): 894–906. http://dx.doi.org/10.1680/jmacr.18.00052.

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COSENZA, EDOARDO, i ANDREA PROTA. "EXPERIMENTAL BEHAVIOUR AND NUMERICAL MODELLING OF SMOOTH STEEL BARS UNDER COMPRESSION". Journal of Earthquake Engineering 10, nr 3 (maj 2006): 313–29. http://dx.doi.org/10.1080/13632460609350599.

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Hidaka, Souta, Yosuke Suzuishi i Norimichi Kitagawa. "Investigating the Effects of Tactile Masking and Surface Texture on the Velvet Hand Illusion". Perception 47, nr 10-11 (październik 2018): 1070–80. http://dx.doi.org/10.1177/0301006618805335.

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When we hold thin metallic bars between the palms of our hands and rub the palms against each other, the feeling of touching smooth velvet occurs. Previous studies have shown that tactile motion and pressure on the palms are important for this velvet hand illusion. Interestingly, when we experience this illusion, we cannot feel the texture of our palms as we usually do. In the present study, we investigated the possibility that tactile masking contributes to the occurrence of the velvet hand illusion. We measured vibrotactile detection performance on the palms of the hands during the occurrence of the velvet hand illusion. The detection performance was worse when the illusion occurred than when it did not. Moreover, the degradation of the detection performance correlated positively with the subjective magnitude of the illusion. We also examined whether additional surface texture could affect the occurrence of the illusion and found that the illusion became weaker as the roughness of the surface increased. These findings suggest that tactile motion and pressure information delivered by the bars of smooth surface mask tactile sensations on the palms of the hands, resulting in an illusory smooth, frictionless feeling on the palms.

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13

Uetani, Yasuhiro, Ryotaro Nagata, Hidetoshi Takagi, Kenji Matsuda i Susumu Ikeno. "Simple Manufacturing Method for A7075 Aluminum Alloy Slurry with Fine Granules and Application to Rheo-Extrusion". Solid State Phenomena 116-117 (październik 2006): 746–49. http://dx.doi.org/10.4028/www.scientific.net/ssp.116-117.746.

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Semi-solid slurry of A7075 aluminum alloy with fine solid granules was tried simply to make by passing the melt through upright tube followed by inclined water-cooled tube. Structures of solidified slurries were granular and mean grain sizes of about 0.06 to 0.11mm could be obtained. When the slurries introduced into an extrusion container kept at semi-solid temperature 873K were extruded to round bars at various extrusion ratios and press ram speed of 10mm/s, just after cooling to 833K, they could easily be extruded to bars with smooth surfaces at lower forces. Although every tensile strength of extruded bars were lower than that of hot-extruded one, there was a tendency that finer the solid granules in slurry, higher the tensile strength of extruded bar.

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14

Bamonte, Patrick, Dario Coronelli i Pietro G. Gambarova. "Smooth Anchored Bars in NSC and HPC: a Study on Size Effect". Journal of Advanced Concrete Technology 1, nr 1 (2003): 42–53. http://dx.doi.org/10.3151/jact.1.42.

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15

Xu, X. X., Q. C. Cai i Y. Su. "A tensile stress criterion for cleavage in precracked, notched and smooth bars". International Journal of Fracture 50, nr 1 (lipiec 1991): 51–65. http://dx.doi.org/10.1007/bf00035168.

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Prota, Andrea, Fiorenzo de Cicco i Edoardo Cosenza. "Cyclic Behavior of Smooth Steel Reinforcing Bars: Experimental Analysis and Modeling Issues". Journal of Earthquake Engineering 13, nr 4 (4.05.2009): 500–519. http://dx.doi.org/10.1080/13632460902837686.

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Uetani, Yasuhiro, Ryotaro Nagata, Hidetoshi Takagi, Kenji Matsuda i Susumu Ikeno. "Effect of Granule Size in Semi-Solid Slurry on Rheo-Extrusion of A7075 Aluminum Alloy". Materials Science Forum 561-565 (październik 2007): 291–94. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.291.

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Rheo-extrusions of A7075 aluminum alloy were carried out utilizing semi-solid slurries with different solid granule sizes, which were made by a simple method combined a thin upright tube with a water-cooled tube. Every structure of slurries was granular and average solid granule sizes could be controlled by 0.05 to 0.11mm. These slurries were extruded to round bars at extrusion ratio of 36 and press ram speed of 10mm/s mainly, just after cooling to 833K ( fs > 0.9 ). All of the slurries could easily be extruded to bars with smooth surfaces at much low extrusion forces than those of hot-extrusions. Tensile strength of rheo-extruded bars after solution treatment increased with decreasing of the solid granule size. Peak hardness level at T6 condition equivalent to that of hot-extrusion could be obtained at the finest solid granule size.

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18

Gao, Jing, Penghai Xu, Lingyun Fan i Giovanni Pietro Terrasi. "Study on Bond-Slip Behavior between Seawater Sea-Sand Concrete and Carbon Fiber-Reinforced Polymer (CFRP) Bars with Different Surface Shapes". Polymers 14, nr 13 (30.06.2022): 2689. http://dx.doi.org/10.3390/polym14132689.

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The application of CFRP bar and seawater sea-sand concrete (SSSC) in construction can overcome the shortcomings in conventional reinforced concrete, such as corrosion induced by carbonation and chloride ingress. In this study, the bond-slip behavior between an SSSC cube and CFRP bar has been investigated, and different CFRP bar surface shapes have been considered. A total of 27 specimens (9 groups) were fabricated for a pull-out test, where three types of CFRP bar with different surface shapes were used: smooth regular bars, double-wrapped bars and ribbed bars. Bond strength, bond-slip curve, and failure mode have been presented and discussed. FE models have been constructed and validated by experimental results. The effect of concrete compressive strength and relative area of ribs on bond strength has been studied through numerical simulations. It is found that the bond strength increased with concrete compressive strength, and the ribbed bar had significantly higher bond strength than the smooth regular bar. Pull-out failure was observed when the cover-depth-to-bar-diameter ratio was no less than 4 and, otherwise, splitting failure occurred. In addition, a simple formula has been proposed to approximately evaluate the bond strength between an SSSC cube and CFRP bar and validated by experimental results, and analytical expressions for different bond-slip curves have also been developed.

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Orlandi, Paolo, i Sergio Pirozzoli. "Secondary Flow in Smooth and Rough Turbulent Circular Pipes: Turbulence Kinetic Energy Budgets". Fluids 6, nr 12 (10.12.2021): 448. http://dx.doi.org/10.3390/fluids6120448.

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Direct Numerical Simulations have been performed for turbulent flow in circular pipes with smooth and corrugated walls. The numerical method, based on second-order finite discretization together with the immersed boundary technique, was validated and applied to various types of flows. The analysis is focused on the turbulence kinetic energy and its budget. Large differences have been found in the near-wall region at low Reynolds number. The change in the near-wall turbulent structures is responsible for increase of drag and turbulence kinetic energy. To investigatselinae the effects of wall corrugations, the velocity fields have been decomposed so as to isolate coherent and incoherent motions. For corrugated walls, we find that coherent motions are strongest for walls covered with square bars aligned with the flow direction. In particular, the coherent contribution is substantial when the bars are spaced apart by a distance larger than their height. Detailed analysis of the turbulence kinetic energy budget shows for this set-up a very different behavior than for the other types of corrugations.

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20

Xu, Xin Sheng. "Experimental Study and Numerical Simulation of Bond Behaviors Between FRP Bar and Concrete". Advanced Materials Research 168-170 (grudzień 2010): 2134–38. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.2134.

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Surface-adhering-sand screw-thread-form FRP bar was produced. By symmetrical pull-out test research to a certain depth in FRP (Fiber Reinforced Polymer) bar concrete, the bond mechanism, the failure mechanism, the bond strength and the slip of FRP bar to concrete were studied systematically. Studies show that the failure mode is not the damage of the ribs or the shearing off of the ribs, but is shear failure between the screw thread and the core of the FRP bar, and the sands on the surface of the bar were grinded into powder. The descending branch of load-slip curve for the FRP bars is gentler than that for the steel bars. The bond strength of FRP bars is a little lower than that of steel bars, but higher than smooth FRP bar greatly. At last the FRP bar concrete specimen were modeled in ANSYS program and the simulation result is satisfactory, which proves the feasibility to model the behavior of bond-slip relationship between FRP bar and concrete accurately.

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Nagata, Ryotaro, Yasuhiro Uetani, Hidetoshi Takagi, Kenji Matsuda i Susumu Ikeno. "Rheo-Extrusion of A7075 Aluminium Alloy Utilizing Semi-Solid Slurry Manufactured by Simple Method". Materials Science Forum 519-521 (lipiec 2006): 1847–52. http://dx.doi.org/10.4028/www.scientific.net/msf.519-521.1847.

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In order to extrude A7075 aluminum alloy soundly from melt without using feed stock billet, rheo-extrusion was tried by utilizing semi-solid slurry with fine solid granules made by employing cooling tube. When the melt moving down inside thin tube was adequately cooled in different ways and introduced into an extrusion container kept at semi-solid temperature of 873K, structure of solidified slurries were granular and mean grain sizes of about 60 to 120μm could be obtained. Subsequently, these slurries were extruded to round bars at various extrusion ratios (28 to 64) and press ram speed of 10mm/s, just after cooling to 833K. The newly developed slurries could easily be extruded to bars with smooth surfaces at lower forces. Although every tensile strength of extruded bars were lower than that of hot-extruded one, there was a tendency that finer the solid granules in slurry, higher the tensile strength of extruded bar.

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22

Naotunna, Chavin N., S. M. Samindi M. K. Samarakoon i Kjell T. Fosså. "Experimental investigation of crack width variation along the concrete cover depth in reinforced concrete specimens with ribbed bars and smooth bars". Case Studies in Construction Materials 15 (grudzień 2021): e00593. http://dx.doi.org/10.1016/j.cscm.2021.e00593.

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Xu, Gang, Jun Zeng, Qing Wang, Xuan Xiang i Ze-zhong Wei. "Bond Stress-Slip Model for Concrete-Embedded Smooth Bars in Salt-Frozen Environment". IOP Conference Series: Earth and Environmental Science 304 (18.09.2019): 052081. http://dx.doi.org/10.1088/1755-1315/304/5/052081.

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Wang, Xiao Lu, i Da Yu Huang. "Thermal Analysis and Design Applications of the Spiral Groove Tubes in Condensers". Advanced Materials Research 1070-1072 (grudzień 2014): 1705–8. http://dx.doi.org/10.4028/www.scientific.net/amr.1070-1072.1705.

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In this paper, condensation mechanism of the Freon refrigerants outside spiral grooved tube is discussed. The heat transfer coefficient of Freon refrigerants condensation outside spiral grooved tube is obtained. A calculation example of heat transfer coefficient on the tube bundle of condenser with baffle bars is presented. It shows the excellent thermal performance of the spiral groove tubes compared to smooth tubes.

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Kinoshita, Masaharu, Charles D. Gilbert i Aniruddha Das. "Optical Imaging of Contextual Interactions in V1 of the Behaving Monkey". Journal of Neurophysiology 102, nr 3 (wrzesień 2009): 1930–44. http://dx.doi.org/10.1152/jn.90882.2008.

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Interactions in primary visual cortex (V1) between simple visual elements such as short bar segments are believed to underlie our ability to easily integrate contours and segment surfaces. We used intrinsic signal optical imaging in alert fixating macaques to measure the strength and cortical distribution of V1 interactions among collinear bars. A single short bar stimulus produced a broad-peaked hill of activation (the optical point spread) covering multiple orientation hypercolumns in V1. Flanking the bar stimulus with a pair of identical collinear bars led to a strong nonlinear suppression in the optical signal. This nonlinearity was strongest over the center bar region, with a spatial distribution that cannot be explained by a simple gain control. It was a function of the relative orientation and separation of the bar stimuli in a manner tuned sharply for collinearity, being strongest for immediately adjacent bars lying on a smooth contour. These results suggest intracortical interactions playing a major role in determining V1 activation by smooth extended contours. Our finding that the interaction is primarily suppressive when imaged optically, which presumably reflects the combined inhibitory and excitatory inputs, suggests a complex interplay between these cortical inputs leading to the collinear facilitation seen in the spiking response of V1 neurons. This disjuncture between the facilitation seen in spiking and the suppression in imaging also suggests that cortical representations of complex stimuli involve interactions that need to be studied over extended networks and may be hard to deduce from the responses of individual neurons.

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Lin, Xiao Shan, i Yi Xia Zhang. "Finite Element Analysis of FRP-Reinforced Concrete Beams with Bond-Slip Effect". Applied Mechanics and Materials 553 (maj 2014): 661–66. http://dx.doi.org/10.4028/www.scientific.net/amm.553.661.

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In this paper, several FRP-reinforced concrete beams are modelled using a recently developed one-dimensional two-node layered composite beam element which accounts for the bond-slip between reinforcing bars and the surrounding concrete. Effect of different surfaces of FRP reinforcing bars on the structural response of FRP-reinforced concrete beams with bond-slip effect is also investigated. It is found that the type of rebar surface has a significant influence on bond strength and structural behaviour, and that the grain-covered surface provides the best bond between the FRP rebars and concrete, the smooth surface the worst, and FRP rebars with ribbed and braided surfaces perform similarly. Keywords: Bond-slip; Composite beam element; FRP-reinforced concrete beam; Nonlinear finite element analysis

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Jasiński, Radosław. "NUMERICAL ANALISIS OF THE STRAINS AND STRESS STATES REINFORCED CLAY BRICK MASONRY WALLS HORIZONTALLY SHEARED". International Journal of Engineering Technologies and Management Research 5, nr 8 (21.03.2020): 20–37. http://dx.doi.org/10.29121/ijetmr.v5.i8.2018.277.

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This paper presents the results: stress and strain of bed joints mortar, masonry units, reinforcement bars and mechanism of cracking of numerical simulations using ANSYS of reinforced brick wall in the horizontal shear. Willam-Warnke (WW-5) failure criterion for mortar and bricks and Huber-Mises-Hencky (HMH) plasticity surface for bed joints steel reinforcement (steel smooth bars and truss type reinforcement) has been used. Coulomb-Mohr (CM) criterion in the contact surfaces of mortar and bricks have been used in the interface elements. Numerical calculations showed satisfactory convergence of research in the patterns of cracking; and the load-strain relationship was similar to the results of research with regard only to the cracking time. Destructive force numerical models Hu,cal correspond to the forces observed at the first cracks in the walls Hu,mv. Reduction of transverse and longitudinal deformation of mortar bed joints have been reported in the immediate vicinity of the bars, and the reduction of the main stress of the bricks is reported in the case of the use reinforcement.

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Kim, Do Hyung, Jin Won Kim, Yeon Soo Na i Chi Yong Park. "Investigation of Local Failure Criteria of Wall-Thinned Area by Simulated Specimen Tests". Key Engineering Materials 326-328 (grudzień 2006): 1165–68. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.1165.

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The objective of this study is to develop a local failure criterion at wall-thinning defect of piping components. For this purpose, a series of tensile tests was performed using several types of specimens with different stress state under tension, including smooth bars, notched round bars and grooved plates. In addition, finite element (FE) simulations were performed for all tests, and its results were compared to the test results. From the comparisons, the equivalent stress and strain corresponding to maximum load and final failure of the notched round bar specimens were proposed as the local failure criterion which is a function of stress triaxiality at notched area. The criteria were verified by employing them to the estimation of maximum load and final failure of grooved plate specimen tests.

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Brooker, Jack E., Madeleine K. Bruce, Wendy Chen, Robert Hashemi, Joseph E. Losee, Jesse A. Goldstein i Lindsay A. Schuster. "Clinical and Radiological Analysis of Arch Bars Over-Retained for 14 years Post Maxillo-Mandibular Fixation". FACE 2, nr 3 (4.07.2021): 300–304. http://dx.doi.org/10.1177/27325016211026336.

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Maxillo-mandibular fixation (MMF) is common technique used in mandibular fractures to stabilize the fragments and maintain the patient in normal dental occlusion during the healing process. Arch bars with elastics are one of the most frequently used methods of MMF and are temporary, and designed to be removed after the healing process is completed. There is controversy as to what impact the hardware has on dental hygiene and oral health. No reports of long-term retention of the hardware exist. This report details the case of arch bars retained for 14 years. The patient underwent MMF and internal fixation at age 16 for a complex mandibular fracture and failed to follow-up for timely removal of the arch bars due to loss of insurance. He presented at age 30 with dental pain and returned to the treating center for removal. He was in normal occlusion, but general indices of dental and periodontal health were extremely poor with multiple non-restorable teeth despite reporting good oral hygiene in the intervening period. A decline in overall dental health was evident at 1 year following removal of arch bars. Due to the presence of smooth surface dental caries, it was concluded that the presence of the arch-bars had exacerbated already poor oral hygiene and contributed to the extensive dental pathology seen. This case highlights the need for timely follow-up and hardware removal. Understanding each patient’s individual social and financial circumstances is essential to this process and a formalized office recall process may have prevented this complication.

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Tang, Fujian, Genda Chen, Richard Brow i Michael Koenigstein. "Corrosion Resistance of a Sand Particle-Modified Enamel Coating Applied to Smooth Steel Bars". Materials 7, nr 9 (15.09.2014): 6632–45. http://dx.doi.org/10.3390/ma7096632.

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Bousias, Stathis, Alexis-Loukas Spathis i Michael N. Fardis. "Seismic Retrofitting of Columns with Lap Spliced Smooth Bars Through FRP or Concrete Jackets". Journal of Earthquake Engineering 11, nr 5 (14.08.2007): 653–74. http://dx.doi.org/10.1080/13632460601125714.

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Di Sarno, L., C. Del Vecchio, G. Maddaloni i A. Prota. "Experimental response of an existing RC bridge with smooth bars and preliminary numerical simulations". Engineering Structures 136 (kwiecień 2017): 355–68. http://dx.doi.org/10.1016/j.engstruct.2017.01.052.

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Verderame, Gerardo M., Paolo Ricci, Gaetano Manfredi i Edoardo Cosenza. "Ultimate chord rotation of RC columns with smooth bars: some considerations about EC8 prescriptions". Bulletin of Earthquake Engineering 8, nr 6 (3.06.2010): 1351–73. http://dx.doi.org/10.1007/s10518-010-9190-x.

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He, Peng, Kang Ling Fang i Xin Hai Liu. "Improved Watershed Algorithm Based on Morphology and Distance Transform". Applied Mechanics and Materials 333-335 (lipiec 2013): 1071–75. http://dx.doi.org/10.4028/www.scientific.net/amm.333-335.1071.

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In this paper we proposed an improved watershed algorithm for the quasi-circle overlapping images of the bars end face. According to the classical watershed algorithm, which often causes over-segmentation, the improved algorithm does a series of pretreatment with the original image, such as sobel filter. With the gradient operator and mathematical morphology method, we firstly obtain the smooth image of the forced local maximum marks. Then, on the basis of the quasi-circle characteristic of the target image, we proceed to maximize the erosion with circular structure in order to prevent under-segmentation. Finally, we use the watershed algorithm to segment the gray image based on distance transform. So we can separate the target from each other to achieve the accurate counting purpose. By using the proposed algorithm in the article, we obtain satisfactory segmentation results of the quasi-circle overlapping image of the bars end face image.

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35

Li, Xin‐Ru, Zhi‐Min Wu i Jian‐Jun Zheng. "Dynamic bond stress‐slip model for smooth bars in concrete under transverse tensile‐compressive stresses". Structural Concrete 22, nr 3 (17.02.2021): 1633–51. http://dx.doi.org/10.1002/suco.202000579.

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Burr, D. C., M. C. Morrone i J. Ross. "Compression of Visual Space before Saccades". Perception 26, nr 1_suppl (sierpień 1997): 100. http://dx.doi.org/10.1068/v970052.

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We studied how the human visual system recalibrates visual coordinates to compensate for saccadic eye movements. Observers made 20 horizontal saccades to a target on an otherwise featureless red screen, and reported the apparent position of a vertical green bar that was briefly displayed before, during, or after the saccade. Bars presented 50 ms before the beginning of the saccade, or after its completion, were perceived accurately and veridically. However, bars presented immediately prior to the saccade were systematically mislocated, either in the direction of the saccade or in the opposite direction, depending on the spatial position of the bar. This result has been verified by various techniques including Vernier offset estimation, and a forced-choice annulling task. When four bars (straddling the saccade target) were displayed in the interval −25 to 0 ms, they were seen to be merged into 1 bar (forced choice). None of these effects could be mimicked by causing the scene to move at saccadic speeds and amplitudes. The results suggest that each saccade is accompanied by a non-visual signal that displaces the retinal coordinate system, and a momentary compression of visual space. The perceptual compression may be instrumental in ensuring a smooth transition from fixation to fixation.

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Le, Anh-Tuan, Thuy Ninh Nguyen i Vui Van Cao. "Bond-slip Behaviour of NSM GFRP Bars in Reinforced Recycled-Aggregate Concrete: Experiments and a Modified Model". Civil Engineering Journal 9, nr 2 (1.02.2023): 233–53. http://dx.doi.org/10.28991/cej-2023-09-02-01.

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Bond-slip behaviour of glass fiber-reinforced polymer (GFRP) bars embedded in conventional concrete has been widely investigated. In contrast, the bond-slip behaviour of near-surface mounted (NSM) GFRP bars bonded in reinforced recycled aggregate concrete (RAC) seems to be less explored, while recycled materials have been increasingly used due to reasons of environmental pollution and resource exhaustion. This study aimed to experimentally and theoretically examine the bond-slip behaviour of NSM GFRP bars in reinforced RAC under monotonic and cyclic loadings. To achieve this aim, twenty-four tests were performed, which were divided into two groups by monotonic and cyclic loadings. In each group, twelve tests were performed on ten reinforced RAC specimens and two reinforced normal aggregate concrete (NAC) specimens. The test results confirmed the brittle shear failure of concrete in the proximity of a resin-concrete surface. Bond-slip behaviour can be characterized by nonlinear and linear branches, in which the linear branch dominates the behaviour. Under monotonic and cyclic loadings, the average slips of GFRP bars in reinforced RAC were 0.238 and 0.284 mm, and their coefficients of variation (COV) were relatively large at 0.142 and 0.130, respectively. In contrast, ultimate loads had a relatively low COV of around 0.038. The effect of cyclic loading significantly increased the ultimate slip by 19.3%, whereas it negligibly reduced the ultimate load; consequently, the stiffness was reduced by 19.4%. A modified smooth model was proposed to predict the bond-slip behaviour of NSM GFRP bars in reinforced RAC under monotonic and cyclic loadings. The simplicity and accuracy of the model can be useful for engineers in structural retrofitting using NSM FRP technique. Doi: 10.28991/CEJ-2023-09-02-01 Full Text: PDF

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Razdobreev, V. G., i D. G. Palamar. "Modern trends in the production of corrosion-resistant and fire-resistant stress-free reinforcing bars". Fundamental and applied problems of ferrous metallurgy, nr 34 (2020): 170–89. http://dx.doi.org/10.52150/2522-9117-2020-34-170-189.

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The aim of this work is to study modern methods of production of corrosion-resistant and fire-resistant stress-free reinforcing bars in the world. Non-stressed reinforcing bars are used as working, structural and assembly reinforcement in conventional building structures, as well as in various types of prestressed structures: from openwork prefabricated to huge monolithic hydraulic structures, therefore, its assortment produced by the domestic metallurgical industry in the range from 5,5 to 40 mm in the nominal diameter of a smooth profile and from 6,0 to 40 mm for a periodic profile. Recently, in the world, much attention is paid to the design and construction of buildings and structures with an improved complex of consumer properties, intended, in particular, for work in corrosive and fire hazardous environments. Such developments are not currently being conducted in Ukraine. In the world and in Europe, to increase corrosion resistance and fire resistance, as well as for the manufacture of seismically resistant reinforcing bars (δmax≥7,5 %), hot-rolled low-alloyed (additionally alloyed with V and Mo) and microalloyed steel grades without the use of heat treatment or cold-deformed (cоld stretched) from hot rolled strip of periodic profile. In GOST 34028-2016 for the countries of the Customs Union, it is clearly stated that for the reinforcement of prefabricated reinforced concrete structures and monolithic reinforced concrete, unstressed reinforcing bars in bars or coils with a nominal diameter of 4,0 to 40 mm are also used for the production of such rolled products, low-carbon and low-alloy steel grades are used, which microalloy V, Nb, Mo or add nitride-forming elements Al, Ti, V, Nb. In this case, either hot rolling or cold deformation or heat treatment in the flow of the rolling mill is used. An alternative way of producing corrosion-resistant and fire-resistant stress-free reinforcing bars in the world is the use of stainless steel as a material. Such profiled reinforcing bars are produced in the range of 3,0 to 50 mm by hot rolling or cold deformation. The use of modern technologies for the production of stainless steel reinforcing bars, starting with the addition of effective and high-quality alloying elements and additives in the production of liquid steel and effective methods of metal pressure treatment, which allows us to guarantee the material saving from corrosion and high temperatures in case of fire. A significant disadvantage of this rolled product is its rather high cost.

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Gonçalves Júnior, Eliezer Senna, Emílio Alberto Amaral Soares, Sonia Hatsue Tatumi, Marcio Yee i Juan Carlos Ramirez Mittani. "Pleistocene-Holocene sedimentation of Solimões-Amazon fluvial system between the tributaries Negro and Madeira, Central Amazon". Brazilian Journal of Geology 46, nr 2 (czerwiec 2016): 167–80. http://dx.doi.org/10.1590/2317-4889201620160009.

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ABSTRACT: In the scope of Solimões-Amazon fluvial system between the Negro and Madeira tributaries, three levels of Quaternary fluvial terraces overlie the Alter do Chão and Novo Remanso formations further than 100 km southward its current main channel. Smooth undulated topography presenting low drainages density formed by sparse secondary plain channels and rounded lakes characterizes these deposits. Internally, they show point bars morphology constituted by intercalated layers of mud (silt and clay) and sand forming an inclined heterolithic stratification. The asymmetric distribution of fluvial terraces allied to the records of old scroll-bars features and paleochannels in many extensions of the Solimões River suggests the predominance of a meander pattern between 240 to 6 kyears. On the other hand, the development of the current anabranching pattern took place in the last six kyears due to the Holocene sea-level rise, besides the action of neotectonics and rainforest establishment related to the increase of humidity in Amazonia.

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Toribio, Jesús, Beatriz González, Juan-Carlos Matos i Iván González. "Notch Effects on the Stress Intensity Factor and on the Fatigue Crack Path for Eccentric Circular Internal Cracks in Elliptically Notched Round Bars under Tensile Loading". Materials 15, nr 24 (19.12.2022): 9091. http://dx.doi.org/10.3390/ma15249091.

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In this paper, stress intensity factor (SIF) solutions are numerically obtained for notched bars subjected to tensile loading containing an eccentric circular inner crack located in the cross-section corresponding to the notch root. The finite element method and the J-integral have been used to obtain the SIF and to analyze the effect on it of three elliptical notch geometries (of equal radial depth). The results show how the SIF is greater in the notched bars than in the smooth bar and within the former when the axial semi-axis of the notch rises, its effect being greater as the diameter and eccentricity of the inner crack increase. In addition, the fatigue growth of an eccentric crack induces an increase in such eccentricity, greater as the notch axial semi-axis increases. The cause of these phenomena can be attributed to the constraint loss caused by the notch, which also facilitates bending of the specimen due to the asymmetry generated by the crack eccentricity.

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Fiteni, Karl, Joseph Caruana, João A. S. Amarante, Victor P. Debattista i Leandro Beraldo e Silva. "The relative efficiencies of bars and clumps in driving disc stars to retrograde motion". Monthly Notices of the Royal Astronomical Society 503, nr 1 (5.03.2021): 1418–30. http://dx.doi.org/10.1093/mnras/stab619.

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ABSTRACT The presence of stars on retrograde orbits in disc galaxies is usually attributed to accretion events, both via direct accretion, and through the heating of the disc stars. Recent studies have shown that retrograde orbits can also be produced via scattering by dense clumps, which are often present in the early stages of a galaxy’s evolution. However, so far it has been unclear whether other internally driven mechanisms, such as bars, are also capable of driving retrograde motion. Therefore, in this paper, we investigate the efficiencies with which bars and clumps produce retrograde orbits in disc galaxies. We do this by comparing the retrograde fractions and the spatial distributions of the retrograde populations in four N-body+smooth particle hydrodynamics (SPH) simulations of isolated disc galaxies spanning a range of evolutionary behaviours. We find that both bars and clumps are capable of generating significant retrograde populations of order ${\sim}10{{\ \rm per\ cent}}$ of all stars. We also find that while clump-driven retrograde stars may be found at large galactocentric radii, bar-driven retrograde stars remain in the vicinity of the bar, even if the bar dissolves. Consequently, we find that retrograde stars in the Solar neighbourhood in the clumpy models are exclusively clump-driven, but this is a trace population, constituting $0.01\!-\!0.04{{\ \rm per\ cent}}$ of the total stellar population in this region. Finally, we find that neither bars (including dissolving ones) nor clumps in the models are able to produce rotationally supported counterrotating discs.

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42

Chukwunonye, C. U., Nicholas J. Jones i Gabriela Petculescu. "Sensitization in Aluminum Alloys: Effect on Acoustic Parameters". Corrosion 74, nr 11 (15.08.2018): 1237–44. http://dx.doi.org/10.5006/2832.

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Velocity and attenuation of shear and longitudinal sound waves were measured as a function of sensitization level in AA5083-H116 and AA5456-H116 aluminum alloys using two different techniques: resonant ultrasound spectroscopy (RUS) and pulse echo (PE). The frequency range for RUS was 0.3 MHz to 1 MHz. For PE, longitudinal 3.5 MHz and shear 1 MHz transducers were used. Sensitization was artificially induced in the laboratory by isothermally heating specimens at temperatures of 120°C, 175°C, 185°C, and 240°C for fixed periods of time (12 h to 96 h, the longer times for the lower temperatures). Measurements were repeated after each heating sequence. The overall changes are reported as percent difference between the as received and the fully sensitized states. The quantity that was found to be most sensitive to the degree of sensitization in this study is the attenuation coefficient of longitudinal waves, αL. The measured change in αL exceeds 20%, with error bars within 1% to 4%. Despite the magnitude of the error bars, the αL vs. degree-of-sensitization curve is clear and smooth. The shear wave velocity changed by 1.2% to 1.5%, with error bars within 0.01% to 0.1%. The larger change was observed for the AA5456 alloy, which contains more Mg. The longitudinal wave velocity was found to change by 0.5% for the 5456 alloy, with error bars within 0.004% to 0.02%. The attenuation coefficient for shear waves was not measured. This study identifies multiple ultrasonic parameters that can be combined into a new, on-site, nondestructive tool for quantitatively monitoring the sensitization level in Mg-rich aluminum alloys, with possible extensions to other materials.

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Palios, X., E. Strepelias, N. Stathas, M. N. Fardis, S. Bousias, C. Z. Chrysostomou i N. Kyriakides. "Experimental study of a three-storey concrete frame structure with smooth bars under cyclic lateral loading". Bulletin of Earthquake Engineering 18, nr 13 (27.07.2020): 5859–84. http://dx.doi.org/10.1007/s10518-020-00900-5.

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Sprowl, Tony B., i Dara W. Childs. "A Study of the Effects of Inlet Preswirl on the Dynamic Coefficients of a Straight-Bore Honeycomb Gas Damper Seal". Journal of Engineering for Gas Turbines and Power 129, nr 1 (1.03.2004): 220–29. http://dx.doi.org/10.1115/1.2227416.

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Honeycomb seals are frequently used as replacements for labyrinth seals in high-pressure centrifugal compressors to enhance rotordynamic stability. A concern exists that this enhanced stability will be lost if the honeycomb cavities become clogged. Static and dynamic tests were conducted on a honeycomb and a smooth seal (representing the honeycomb seal with completely clogged cells) at the same constant clearances using air with a supply pressure of 70 bars. The test matrix included three speeds, three pressure ratios, and three inlet preswirl conditions. The results show increased leakage, decreased synchronous stiffness, and decreased dynamic stability for the smooth seal with preswirled flow. The results strongly support the use of swirl brakes at the entrance of a honeycomb seal if clogging is a concern. Comparisons between test results and predictions from a two-control-volume theory by Kleynhans and Childs showed excellent agreement in general.

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45

Avelino, Ricardo Maia, Olivier Baverel i Arthur Lebée. "Design Strategies for Gridshells with Singularities". Journal of the International Association for Shell and Spatial Structures 60, nr 3 (15.09.2019): 189–200. http://dx.doi.org/10.20898/j.iass.2019.201.023.

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This article discusses design strategies to improve the mechanical behavior of elastic gridshells with singularities. The advantage of meshing with one or more singularity is to allow a wider range of surfaces to be meshed with equal-length, quadrilateral meshes, known as Chebyshev nets. However, the application of this meshing process will influence the fabrication and the mechanical behavior of the structures. The erection process is simulated by means of the dynamic relaxation method, bending the bars to their final position. This simulation shows that a facetted shape is found instead of a smooth surface. This deformed shape makes the structure softer under applied gravity load. Two strategies are investigated in this paper to enable the construction of gridshells with singularities. The first consists in extending the bars close to the singularities edge-lines to have a smother gridshell after the erection process. The second strategy applies post-tension cables to the patches to increase the local curvature in the faceted zones. Both strategies increase the stiffness and buckling load of the final structure.

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Saadoon Al-Yassri, Labeeb, Alaa Mahdi Al-Khekany i Hajer Satea Abbas. "Experimental Study of Replacement the Tension Reinforcing Bars in Concrete Beams by Steel Pipes". International Journal of Engineering & Technology 7, nr 4.20 (28.11.2018): 229. http://dx.doi.org/10.14419/ijet.v7i4.20.25931.

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Structures designed with reinforced concrete beams are used extensively in construction projects because of their functional and economic features. In this research, tested concrete beams were cast and reinforced with small diameter steel pipes and /or steel bars as flexural reinforcement to study the effect of this configuration of reinforcement on the structural behavior of reinforced concrete beams. The idea of this research involves performing and testing of four reinforced concrete beams reinforced by small diameter steel pipes with different percentages of replacement with traditional steel bars (0%, 33%, 66% and 100%). The experimental results showed that using of steel pipes reduces the flexural capacity by (2.7, 18.3, 37.5%) if compared with traditional steel bar according to the replacement percentages of (33%, 66%, and 100%) respectively. Moreover, the stiffness of beams reinforced with steel pipes (fully or partially) decreased as a result of the difference in the mechanical properties between steel bar and the steel pipe and also, the bond strength reduction between the smooth steel pipe and surrounded concrete.

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Li, Xiao Yong, i Zhi Gang Zhang. "The Impact of Corrosion on the Mechanical Properties of Smooth Steel Rebar HPB235". Advanced Materials Research 179-180 (styczeń 2011): 28–31. http://dx.doi.org/10.4028/www.scientific.net/amr.179-180.28.

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The Impact of Corrosion on the Mechanical Properties of Smooth Steel Rebar HPB235 The impact of corrosion on the mechanical properties of steel rebar was examined. An experimental investigation was carried out in order to gain better insight of the effect of corrosion on the mass loss, strength, of smooth Steel Rebar HPB235 10 mm diameter steel bars that were artificially corroded for different corrosion levels. Corrosion is a negative contributor on the structural integrity of concrete structures and leads to degradation of the mechanical properties of steel rebar. In order to evaluate the influence of corrosion on the mechanical properties of steel rebar, an experimental investigation was conducted on smooth steel rebar of 10 mm diameters, and which were artificially corroded for 1, 3, 5 and 7 months. The laboratory tests suggest that corrosion duration had a significant impact on the strength degradation of the specimens. The mechanical properties of tensile test before and after corrosion indicated progressive variation and drastic drop in their values. The corrosion enhanced the damage and created pits and notches, resulting in stress concentration points and progressive reduction of strength. It gets the express formula nominal ultimate strength and nominal yield strength.

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Yang, Xiu Hua. "Frost Damage Mechanism Analysis and Preventive Measures of Bridge". Applied Mechanics and Materials 737 (marzec 2015): 414–16. http://dx.doi.org/10.4028/www.scientific.net/amm.737.414.

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In order to guarantee the safety and smooth of road traffic in low temperature season, deicing salt is usually adopted to solute the problem of bridge deck snow. However, the frequent use of de-icing salt causes the salt frozen erosion damage of concrete, at the same time, it induces to internal corrosion of steel bars and concrete material performance, furthermore, it will also result in the bridge structure durability degradation, shorten the service life of the bridge. Aiming at this phenomenon, this paper analyzes the mechanism of concrete frost damage, and put forward the corresponding prevention measures.

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Brommesson, Rebecka, Magnus Hörnqvist i Magnus Ekh. "Low-Cycle Fatigue Crack Growth in Ti-6242 at Elevated Temperature". Advanced Materials Research 891-892 (marzec 2014): 422–27. http://dx.doi.org/10.4028/www.scientific.net/amr.891-892.422.

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During low-cycle fatigue test with smooth bars the number of cycles to initiation is commonly defined from a measured relative drop in aximum load. This criterion cannot be directly related to the actual measure of interest - the crack length. By relating data from controlled crack growth tests under low-cycle fatigue conditions of a high strength Titanium alloy at 350°C and numerical simulation of these tests, it is shown that it is possible to determine the relationship between load drop and crack length, provided that care is taken to consider all relevant aspects of the materials stress-strain response.

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Jokūbaitis, Aidas, i Juozas Valivonis. "An Analysis of the Transfer Lengths of Different Types of Prestressed Fiber-Reinforced Polymer Reinforcement". Polymers 14, nr 19 (20.09.2022): 3931. http://dx.doi.org/10.3390/polym14193931.

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The main aim of this paper is to provide a broader analysis of the transfer lengths of different types of fiber-reinforced polymers (FRPs) and to provide corrections to the existing theoretical models. Therefore, this paper presents a description of the main factors that influence the transfer lengths of different types of FRPs based on experimental results found in the literature. A database of more than 300 specimens was compiled with the results of the transfer lengths of different FRPs and the main influencing parameters. The analysis of the database results showed that the transfer length of the carbon fiber composite cable (CFCC) strands depends on the type of prestressed reinforcement release. Therefore, in this article, the new coefficient αt = 2.4 is proposed for the transfer length of suddenly released CFCC strands. Additionally, the transfer length of the aramid fiber reinforced polymer (AFRP) depends on its surface conditions. Therefore, new coefficients αt = 1.5 and αt = 4.0 are also proposed for the transfer lengths of smooth braided and sanded and rough AFRP bars, respectively. Furthermore, the proposed coefficients αt = 2.6, αt = 1.9, and αt = 4.8 found in the literature were validated with the analysis of a larger database of the transfer lengths of glass fiber-reinforced polymer (GFRP) bars, carbon fiber-reinforced polymer (CFRP) bars, and gradually released CFCC strands, respectively. Moreover, the main existing theoretical models are presented, and the comparison of theoretical and experimental transfer length results is discussed. However, the low number of specimens prestressed with basalt fiber-reinforced polymer (BFRP) bars prevented the deeper analysis of the results. the analysis of the transfer length and the proposed new values of the coefficient αt provides possibilities for adapting it to design codes for engineering applications and performing additional research that fills the missing gaps in the field.

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