• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.1067-1072
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• 2012

Recently, linear motors have been widely researched and have been increasingly used in various industrial applications. Especially, permanent magnet linear synchronous motors(PMLSMs) have been getting the spotlight in the transportation system. A PMLSM is structurally simple and has a lot of merits such as high speed, high thrust force, etc. However, in case of a long stator system which arranges armature to the full length of transportation lines, a PMLSM has some disadvantages such as the material cost increase and long manufacturing time. Hence, in order to overcome these problems, the PMLSM with stationary discontinuous armature structure and concentrated windings was proposed. However, this method occurs undesirable cogging force by outlet edge effect. The cogging force causes thrust force ripples and generates noise and vibration. Therefore, in this paper, we proposed installation method of auxiliary pole PMLSM with concentrated winding applying bifurcating in order to reduce cogging force by the outlet edge when the armature is placed in a discontinuous arrangement. Also, we have examined characteristics of outlet edge cogging force using 2-D finite element analysis(FEA).

• Journal of Korean Society of Steel Construction
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• v.29 no.1
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• pp.81-88
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• 2017

Residual stress is defined as stress that already exists on a structural member from the effects of welding and plastic deformation before the application of loading. Due to such residual stress, welded H-section compression members under centroidal compression load can undergo buckling and failure for strength values smaller than the predicted buckling load and specified compressive strength. Therefore, this study was carried out to evaluate the effect of residual stress from welding on the determination of the buckling load and specified compressive strength of the H-section compression member according to the column length variation. A three-dimensional nonlinear finite element analysis was performed for the H-section compression member where the welded joint was fillet welded by applying heat inputs of 3.1kJ/mm and 3.6kJ/mm using the SAW welding method.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.101-106
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• 1999

Fiber reinforced plastic composites is widely used to make be lightening of aircraft and automotive owing to having high specific strength and specific modulus. And it is very important to know a charge shape in order to have good products in the compression molding. In particular, the product such as a bumper beam is composed of the random and unidirectional composite mats. Its deformation and charge shape are very different by stack type of random and unidirectional mats. In this paper, the characteristics of flow fronts such as a bulging phenomenon for step-type random/unidirectional composite mats and slip parameters are studied numerically. And the effects of viscosity ratio and stack type on the mold filling parameters are also discussed.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.6
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• pp.613-619
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• 2010

The stationary discontinuous armatures that are used in permanent magnet linear synchronous motors (PM-LSMs) have been proposed as a driving source for transportation systems. However, the stationary discontinuous armature PM-LSM contains the outlet edges which always exist as a result of the discontinuous arrangement of the armature. For this reason, the outlet edge cogging force generated between the armature's core and the mover's permanent magnet. This paper contemplated the outlet cogging for ceaccording to 2-D numerical analysis by FEM. We installed the auxiliary pole for in order to minimize the outlet cogging force.

• International Journal of Highway Engineering
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• v.11 no.3
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• pp.151-161
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• 2009

This study was conducted to investigate the characteristics of the curling behavior of long-span pavement slabs under environmental loads. By developing and using finite element models of the long-span pavement slabs, the stress distribution and the effects of slab length, slab thickness, stiffness of underlying layers, and the restraints of the slab ends on the curling behavior were analyzed. In addition, the field experiments were performed with the actual long-span pavement slab to obtain the curling behavior of the real structure under environmental loads. As a result of this study, it was found that the vertical displacements of the long-span pavement slab along the centerline due to the curling behavior were zero except for the areas near the slab ends, and the curling stresses were maximum and constant where the displacements were zero. The slab length and the stiffness of underlying layers did not affect the maximum curling stresses. The restraints at the slab ends made the curling stresses occur near the slab ends, but did not much affect the maximum curling stresses.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.1
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• pp.29-42
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• 2008

The objective of this study is to investigate the effects of rigid end platens on effective stresses in soil mass during consolidation. The friction between the teeth of top cap/base pedestal and the specimen during consolidation decreases the radial and tangential effective stresses in RC specimens. However, it is unpractical to measure the effective stresses in the soil specimen. Two approaches were used to evaluate the state of stress in RC specimens during consolidation. First, careful measurements were made of small strain shear modulus, $G_{max}$ in specimens with carefully controlled void ratios and stress histories, to infer the state of stress. And second, a finite element analysis was performed to analytically evaluate the effect of various soil parameters on the state of stress in RC specimens during consolidation. By combining these experimental and analytical results, an example was performed to predict the average state of stress in RC specimens during consolidation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.2
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• pp.155-166
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• 1988

An "equivalent homogeneous, orthotropic" model that includes edge effects and an accompanying finite element analysis is presented for elastomeric bearings. The model is developed for two-dimensional configurations with horizontal layers, and for linear, elastic, small deformation conditions. The equivalent homogeneous theory, in addition to capturing the overall response characteristics of the layered elastomeric bearing system, approximately models the important edge effects, which occur at and near boundaries that cut the layers, and the stress concentrations at layer interfaces. The primary dependent variables for the theory have been selected such that the highest derivatives appearing in the strain energy function are first-order, thus requiring only $C_0$ continuity of the finite element approximations. As a result, the finite element analysis is simple and computationally efficient. Numerical examples are presented to verify the theory and to illustrate potential applications of the analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.1
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• pp.83-88
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• 2013

Progressive collapse is a chain reaction of failures propagating throughout a portion of a structure that is disproportionate to the original local failure. When column members are subjected to unexpected load (compression load), they will buckle if the applied load is greater than the critical load that induces buckling. The post-buckling strength of the columns will decrease rapidly, but if there is enough residual strength, the members will absorb the potential energy generated by the impact load to prevent progressive collapse. Thus, it is necessary to identify the relationship of the load-deformation of a column member in the progressive collapse of a structure up to final collapse. In this study, we carried out nonlinear FEM analysis and based on deflection theory, we investigated the load-deformation relationship of H-section steel columns when both ends were fixed.

• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.521-528
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• 2017

In this study, vertical loading tests were conducted to investigate the nonlinear behaviors of the fastening systems that have generally been used in the concrete track of domestic railway lines. Nonlinear load-displacement curve models were derived based on the test results. The uplift forces generated in the fastening systems were evaluated by applying the derived nonlinear models as well as the existing linear models. The influence of the factors on the maximum uplift force of the fastening system was analyzed through a parameter study on the distance between neighboring sleepers, the horizontal distance between the center of the bearing and the nearest fastening system from the deck end, and the height of the bridge girder. From the evaluation results it is known that, for economical track and bridge design, due to deck end deformation, it is necessary to consider the nonlinear behavior of the fastening system in the calculation of the uplift force of the fastening systems.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.430-439
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• 2002

The development of reinforcing steel is required in reinforced concrete structures. The standard hooks that have been widely used for the tensile development in the beam-column joints tend to create difficulties of construction such as steel congestion as the member cross sections are becoming smaller due to the use of higher strength concrete and higher grade steel. Using the reinforcing bars with end mechanical anchoring device (headed reinforcement) provides potential economies in construction such as reduction in development lengths, simplified details, and improved responses to cyclic loadings. In this paper, the pullout strengths and behaviors of the headed reinforcement were experimentally studied. In 33 pullout tests performed using D25 deformed reinforcing bars, the test parameters were embedment depth, edge distance, head size, and the use of transverse reinforcement. The pullout strengths determined from tests closely agreed with the pullout strengths predicted using the CCD method. The pullout strengths increased with increasing embedment depths nd edge distances. The strengths tend to increase with the use of larger heads. From the experimental program where the effect of the transverse reinforcement was examined, a modification factor to the CCD was suggested to represent the effect of such reinforcement that is installed across the concrete failure plane on the pullout strengths.