• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4642-4647
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• 2011

Solution for elastic foundation of plane strain state was derived by the application of variational method. Functions of the transverse distribution of the displacements for the analysis were chosen as linear functions. Loading conditions considered for the analysis were concentrated load and distributed load. Under the loading condition of the concentrated load, surface displacement was decreased drastically as the distance from the point of the loading increased. Under the loading condition of the distributed load, surface displacements were more uniformly distributed beneath the loading area when the ratio of the half of the loading width to the depth(B/H) of the compressible layer was greater. The surface displacement was more quickly converged from the edge of the loading area as the ratio(B/H) increased.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.1
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• pp.32-47
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• 1995

The purpose of this study was to determine the displacement of prosthesis & abutment and the stress distribution patterns induced in the periodontium by applying force to the fixed prosthesis. Two levels of periodontal support were compared using two-dimensional finite element stress analysis after placement of 3unit or 4 unit fixed partial denture(FPD) in case of missing of the lower first molar. Concentrated vertical load was delivered at the cusp tip of the second bicuspid or the central fossa of the pontic. The following results were obtained : 1. The greater the loss of alveolar bone in abutment teeth area, the greater the displacement of FPD and the stress concentration in alveolar bone around abutment. 2. The amount and direction of displacement and distribution of stress in the 4-unit FPD was better than those in the 3-unit FPD. 3. Multiple abutments reduced the amount of mesial and downward displacement of the weaked abutments and more uniformly distributed the stresses.

• Smart Structures and Systems
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• v.9 no.2
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• pp.127-143
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• 2012

The present paper deals with the nonlinear analysis of the functionally graded piezoelectric (FGP) annular plate with two smart layers as sensor and actuator. The normal pressure is applied on the plate. The geometric nonlinearity is considered in the strain-displacement equations based on Von-Karman assumption. The problem is symmetric due to symmetric loading, boundary conditions and material properties. The radial and transverse displacements are supposed as two dominant components of displacement. The constitutive equations are derived for two sections of the plate, individually. Total energy of the system is evaluated for elastic solid and piezoelectric sections in terms of two components of displacement and electric potential. The response of the system can be obtained using minimization of the energy of system with respect to amplitude of displacements and electric potential. The distribution of all material properties is considered as power function along the thickness direction. Displacement-load and electric potential-load curves verify the nonlinearity nature of the problem. The response of the linear analysis is investigated and compared with those results obtained using the nonlinear analysis. This comparison justifies the necessity of a nonlinear analysis. The distribution of the displacements and electric potential in terms of non homogenous index indicates that these curves converge for small value of piezoelectric thickness with respect to elastic solid thickness.

• Journal of the Korean Society of Safety
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• v.34 no.4
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• pp.15-21
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• 2019

In order to secure the safety of various machinery, it is very important to develop a technique for accurately and quickly measuring the cracks generated in the mechanical equipment and evaluating the mechanical characteristics. The evaluation of the mechanical properties is accompanied by an appropriate strain measurement according to the material and crack occurrence of the target structure. Especially, when micro cracks are generated, the evaluation method is very important. Digital image correlation is an optical full field displacement measuring method which is using currently with speckles in the interested area. However the evaluation method and conditions of image distributions have to be considered carefully to measure the crack occurrence because the images of the speckle patterns affect the quality of displacement results. In this study, the speckle pattern density is characterized to improve the accuracy of the measurement method. And also the micro crack initiation is detected by the measured displacement in the adopted speckle pattern distribution. It is shown that the proposed method is useful to determine the density pattern distribution for the accurate measurement and crack detection.

• Structural Engineering and Mechanics
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• v.80 no.6
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• pp.737-747
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• 2021

The objective of seismic resilience is to maintain or rapidly restore the function of a building after an earthquake. An efficient tilt mechanism at the member level is crucial for the restoration of the main structure function; however, the damage resistance of the members should be the main focus. In this study, through a comparison with the classical Flamant theory of local loading in the elastic half-space, an elastomechanical solution for the axial-stress distribution of a reinforced-concrete (RC) rocking column was derived. Furthermore, assuming that the lateral displacement of the rocking column is determined by the contact surface rotation angle of the column end and bending and shear deformation of the column body, the load-lateral displacement mechanical model of the RC rocking column was established and validated through a comparison with finite-element simulation results. The axial-compression ratio and column-end strength were analyzed, and the results indicated that on the premise of column damage resistance, simply increasing the axial-compression ratio increases the lateral loading capacity of the column but is ineffective for improving the lateral-displacement capacity. The lateral loading and displacement of the column are significantly improved as the strength of the column end material increases. Therefore, it is feasible to improve the working performance of RC rocking columns via local reinforcement of the column end.

• Journal of the Korean Ceramic Society
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• v.33 no.5
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• pp.602-615
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• 1996

The purpose of the present study is to investigate the microstructural effect on the R-curve behavior in three aluminas with different grain size distributions by analyzing the bridging stress distribution. The crack opening displacement (COD) according to the distance behind the stationary crack tip was measured using an in situ SEM fracture method. The measured COD values in the fine-grained alumina agreed well with Wiederhorn's sollution while they deviated from Wiederhorn's solution in the two coarse-grained aluminas because of the increase of the crack closure due to the grain interface bridging in the crack wake. A numerical fitting procedure was conducted by the introduction of the power-law relation and the current theoretical model together with the measured COD's in order to obtain the bridging stress distribution. The results indicated that the bridging stress function and the R-curve computed by the current model were consistent with those computed by the power-law relation providing a reliable evidence for the bridging stress analysis of the current model. The strain-softening exponent in the power-law relation n, was calculated to be in the range from 2 to 3 and was closely related to the grain size distribution. Thus it was concluded from the current theoretical model that the grain size distribution affected greatly the bridging stress distribution thereby resulting in the quantitative analysis of microfracture of polycrystalline aluminas through correlating the local-fracture-cont-rolling microstructure.

• Journal of the Korean Society for Railway
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• v.9 no.6 s.37
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• pp.798-803
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• 2006

The suspension elements like primary coil spring, yaw damper, body to body damper are core parts of high speed railway bogie and the faults relating to these elements are reported recently. Thus, this study is started to analyze the displacements characteristics of suspension elements of high speed railway rolling-stock for the purpose of preventing the faults and developing the maintenance technology for suspension elements like spring and dampers. For this purpose, we made a plan to measure the displacements of the primary coil spring, yaw damper and body to body damper in actual running condition. We developed the measurement device to measure the longitudinal displacement and angular displacement of suspension elements and installed this device to test suspension elements. Test to measure displacements of suspension elements is conducted in service line of high speed railway. The displacement data which is acquired from the test with actual vehicles was analyzed for its maximum displacement depending on the track sections. As a result of analysis, we obtained the displacement trends occurring with the sections and valuable results like maximum values and the displacement distribution.

• Journal of Aerospace System Engineering
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• v.14 no.2
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• pp.28-35
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• 2020

In this paper, we present a design for a retraction-type actuator (ReACT) that has the characteristics of both thermomechanical metamaterials and displacement amplification mechanisms. The ReACT consists of an actuating bar, a diamond-shaped displacement amplification (DA) structure, and a slot for loading thin-film heaters formed through the actuating bar. When power is supplied to the thin film heater, the actuating bars contacting the heater thermally expand, and the diamond-shaped DA structures retract in the longitudinal direction. The performance characteristics of the ReACT, such as temperature distribution and retracting displacement, were calculated with thermomechanical analysis methods using the finite element method (FEM). Subsequently, the ReACTs were fabricated using a polymer-based 3D printer that can easily execute complex structures, and the performance of the ReACT was evaluated through repeated tests under various temperature conditions. The results of the performance evaluation were compared with the results of the FEM analysis.

• Electrical & Electronic Materials
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• v.9 no.9
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• pp.954-963
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• 1996

Particle displacement distributions of the fundamental thickness shear vibration mode and overtone modes in an energy-trapped single resonator and an energy-trapped double acoustically coupled filter were calculated. The effects of the width of a pair of partial eletrodes and the magnitude of the plate back of the resonator on the particle displacement distributions of its symmetric vibration mode and anti-symmetric vibration mode were investigated. And the effects of the width of a pair of partial eletrodes, the width of the gap between two pairs of partial electrodes and the magnitude of the plate back of the filter on the particle displacement distributions of its symmetric vibration mode and anti-symmetric vibration mode were investigated.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.369-376
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• 1998

The purpose of the present study is to analyze the response of pipelines subjected to liquefaction-induced permanent ground displacement and to discuss the failure prediction of domestic waterway pipelines. Initially here, characteristics of liquefaction are reviewed and then permanent ground displacement is investigated base on previous earthquake hazard cases. Next, considering the distribution of the transverse permanent ground displacement and equivalent spring constant effect, formulas obtained by a beam theory are established to analyze continuous pipelines. This analysis was performed without consideration of axial effects. So the finite element analysis was used in order to consider the axial stiffness of soil. As a result, degree of liquefaction, width of deformed ground and axial stiffness are crucial points for evaluation the failure of pipelines subjected to permanent ground displacement.