• Progress in Superconductivity and Cryogenics
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• v.12 no.2
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• pp.5-8
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• 2010

In this study, the effect of bending strain on the transport property and critical current of lap and butt-jointed (non-laminated) BSCCO tapes has been investigated. The samples were joined using a mechanically controlled jointing procedure. To achieve a uniform thickness at the joint a single point loading contact has been devised. GFRP mandrels with different bending radii which support the sample during bending have been used. $I_c$ have been measured at 77 K and self field. In the case of easy bending test for jointed BSCCO tapes, sudden degradation of $I_c$ is caused by the local strain concentration due to non uniform deformation at the edge parts of the joint. In the case of hard bending test of jointed BSCCO tapes transverse macroscopic crack at specific subsection caused a large $I_c$ degradation. The transport property of jointed BSCCO tapes in each bending mode was discussed with the damage morphology occurred.

• Journal of Aerospace System Engineering
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• v.1 no.4
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• pp.28-36
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• 2007

This paper presents critical buckling loads of laminated composites under cylindrical bending. In-plane displacements are assumed to vary exponentially through plate thickness. The accuracy of this theory is examined for symmetric/antisymmetric cross-ply, angle-ply and unsymmetric laminates under cylindrical bending. Analytical solutions are provided to investigate the effect of transverse shear deformation on critical buckling loads of the laminated plates, and the results are compared with those obtained from the first-order shear deformation plate theory and the classical laminated plate theory.

• Journal of the Korean Society of Safety
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• v.12 no.2
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• pp.27-36
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• 1997

This paper evaluates the static and fatigue bending strengths of CFRP (carbon fiber reinforced plastic) laminates subjected to hygrothermals. The specimens which had different stacking composition, orthotropic and quasi-isotropic laminated plates, were prepared for this experiment. A steel ball launched by the air gun collides against CFRP laminates to generate impact damages, and the 3-point fatigue bending test is carried out by using the impacted laminates to investigate the influence of hygrothermals on the effect on the residual bending fatigue strength of CFRP laminates.

• Journal of the Society of Disaster Information
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• v.3 no.2
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• pp.147-169
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• 2007

This study investigates the reinforcing effects of the Multi-bar Spring nails with respect to the conventional Soil-nails in artificial slopes. Based on wide experience related to design and construction, soil nails have been widely applied to reinforce slope in the world. Multi-bar spring nails are one of the improved soil nailing methods. These method maximizes bending, shearing, pull-out resistance for those multi-nails, not unit nail, that are inserted in the borehole using special spacer at regular intervals. In addition, because cutting plane is confined effect resulting from a pressured plate at the end of the nails with compression spring equipment, slope stability is secured using MS-nailing method. Analyzing bending, pull-out, shearing condition of MS-nail, it was examined throughly elastic region, load transfer capacity, reinforcing effect on cutting plate of MS-nails. In addition, Pilot and laboratory tests, numerical analysis were carried out to verify the superiority of MS-nailing method. In case, MS nailing method is applied to reinforce artificial slope, it was analyzed that bending, pull-out, shearing resistance was increased more than existing nailing method was applied. In this study, it was shown that surface failure was more or less prevented using MS-nailing method, confining effect on cutting plane using spring stuck to flexible equipment.

• Smart Structures and Systems
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• v.14 no.2
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• pp.71-83
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• 2014

The purpose of this paper is to investigate the flexible structure of parabolic shell using photostrictive actuators. The analysis is made to know its dynamic behavior and light-induced control forces for coupled parabolic shell. The effects of an actuator location as well as membrane and bending components under the control action have been analyzed considering the approximate spherical model. The parabolic membrane shell accuracy is being mathematically approximated and validated comparing the light induced control forces using approximate equivalent spherical shell model. The parabolic shell with kapton smart material and photostrictive actuators has been used to formulate the governing equation in the transverse direction. The Kirchhoff-Love assumptions are used to obtain the governing equation of shell with actuator. The mechanical membrane forces and bending moments for parabolic thin shell with actuator is used to analyze the dynamic effect. The results show that membrane control action is much more significant than bending control action. Photostrictive actuators oriented along circumferential direction (actuator-2) can give better control effect than actuators placed along longitudinal direction (actuator-1). The slight difference is observed between spherical and parabolic shell for a surface with focal length to the diameter ratio of 1.00 or more than unity. Space applications often have the shape of parabolical shells or shell of revolution, due to their required focusing, aiming, or reflecting performance. The present approach is focused that photostrictive actuators can effectively control the vibration of parabolical membrane shell. Also, the actuator's location plays an important role in defining the control force.

• Journal of the Korean Wood Science and Technology
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• v.26 no.1
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• pp.87-96
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• 1998

The bending performances were evaluated at the radiata pine plywood through veneer compositions encompassing veneer quality, ply-numbers and overlays of the high density- or medium density-phenol resin impregnated sheets (hereafter abbreviated as resin sheets) on the raw plywood. In addition, a prediction on the bending MOE of veneers and plywoods was carried out by the nondestructive testing with stresswave timer. The summarized results were as follows: I. Bending strength and bending MOE of resin sheets-overlaid plywoods in parallel surface grain direction through 5 and 7ply were increased by 13 to 45% and 17 to 34%, respectively. Resin sheets-overlay occurred an increasing effect of the strength efficiency i.e. strength perpendicular-to-grain direction versus that parallel-to-grain direction, showing the phenomenon that the plywood strength becomes greater at the perpendicular-to-grain direction of 7ply than at that of 5ply. Displacement at bending failure had a greater trend at 7ply than at 5ply, and was decreased by resin sheets-overlay. 2. After the nondestructive bending MOEs were measured for individual veneers, these veneers were rearranged in plywood-manufacture. In these plywoods, including resin sheets-overlay, the actual MOE was predictable with feasibility of $R^2$=0.53, and also the nondestructively-evaluated MOE was lower by 20% in raw plywood, and higher 20% in LVL than actual bending MOEs.

• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1580-1586
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• 2021

The application of induction bending processes to industrial pipe production is increasing. The induction bending process has the effect of reducing the number of inspections and preventing leaks by reducing the weld of the pipe. For these reasons, efforts have been made to apply an induction bending process to the pipe of the PGSFR under development in Korea and this is the first attempt in the SFR design. Since the PGSFR pipe has a relatively large diameter-to-thickness ratio, it is difficult to fabricate an induction bending pipe that meets the requirements. In addition, the material properties may change because the pipe heats to a very high temperature during the induction bending process. In this study, P91 pipes were fabricated by induction bending, and the results from analyzing the induction bending process' applicability to the P91 pipe of the PGSFR are examined. The various dimensional measurements of the pipes fabricated by the induction bending process were surveyed to determine whether the requirements of the ASME Code were met. The minimum thickness, ovality, and wall buckling measured in the fabricated pipe met all the requirements. Tensile, impact, and hardness tests at various locations of the fabricated pipe also satisfied the requirements.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.10 s.253
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• pp.1269-1275
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• 2006

The purpose of this study is to investigate the effect of bend angle on the collapse behavior of locally wall thinned pipe bends. For this purpose, the present study performed three-dimensional finite element analysis on the 30-, 60-, and 90-degree pipe bends with local wall thinning at the center of intrados, extrados, and crown, and evaluated the collapse moment for different thinning dimensions under closing- and opening-mode bending with a constant internal pressure. The results showed that, for intrados and extrados wall thinning, the reduction in the collapse moment due to local wall thinning became significant with decreasing bend angle of pipe bends. This effect of bend angle was enhanced with increasing thinning dimensions, and it was clearer fur opening-mode bending than for closing-mode bending. For crown wall thinning, however, the effect of bend angle was unclear and was less sensitive to the change of wall thinning shapes.

• Structural Engineering and Mechanics
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• v.19 no.6
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• pp.707-720
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• 2005

The bending stress formula that taking into account the transverse deformation is developed for plane-curved, untwisted isotropic beams subjected to loadings that result in deformations in the plane of curvature. In order to account the transverse Poisson contraction effect, a new constitutive relation between force resultants, moment resultants, mid-plane strains and deformed curvatures for a curved plate is derived in a $6{\times}6$ matrix form. This constitutive relation will provide the fundamental basis to the analyses of curved structures composing of isotropic or anisotropic materials. Then, the bending stress formula of a curved isotropic beam can be deduced from this newly developed curved plate theory. The stress predictions by the present analysis are compared to those by the analysis that neglected the Poisson contraction effect. The results show that the Poisson effect becomes more significant as the Poisson ratio and the curvature are getting larger.

• The korean journal of orthodontics
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• v.14 no.1
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• pp.75-92
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• 1984

This study attempted to analyze the distribution of stress, to examine the bending effect in the mandible according to the pulling directions and determine on which pulling directions are adequate when an orthopedic force was applied to the mandible. An orthopedic force, 500gm, was applied to the gnathion, one point of the chin area, in three directions. The three directions were ; high puli' from gnathion to the center of condyle head, and vertical pull, from gnathion to a parallel line with the posterior border of the ramus, and medium pull, from the gnathion to a parallel line with the lower border of mandible. The distribution of principal stress, bending moment and amount of displacement within the mandible was analyzed by a 3-dimensional finite element method and that of the various portions of mandible were computed and compared according to the pulling directions. The results were as follows : 1. The bending moment of each part of a mandible has been found to be markedly larger in case of vertical pull than in case of either high pull or medium pull. In vertical pull the bending moment turned out to largest at the condyle head and neck portion, the gonial angle portion, the coronoid portion and the ascending ramus portion, respectively, while comparatively large at the cuspid and bicuspid portion and the first molar portion. In case of high pull it was largest at the gonial angle portion and becoming smaller at the coronoid portion, the ascending ramus portion, the condyle head and neck portion, and the cuspid and bicuspid portion, in that order. In case of medium pull, however, the bending moment was largest at the condyle head and neck portion, becoming smaller at the first molar portion, the ascending ramus portion, the coronoid portion, the cuspid and bicuspid portion, and gonial angle portion, in that order. 2. As for the bending effect it was calculated to be mostly oriented downward at the mandibular body and backward at the mandibular ramus in both high pull and vertical pull. In case of medium pull it was oriented upward at the mandibular body and forward at the mandibular ramus. 3. The bending effect also turned out to be mostly oriented outward in case of high pull and medium pull, and inward in vertical pull. 4. At the mandibular body and ramus, the bending effect in the upward-downward direction and that in the forward-backward direction were found to be larger than in the inward-outward direction. 5. If and when we expect any correcting effect on the mandibular protrusion by means of the chin cup appliance, we can say sure as conclusion that high pull and vertical pull are more effective than medium pull.