• Proceedings of the KSR Conference
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• 2002.10b
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• pp.1041-1046
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• 2002

A railway open deck plate girder bridge without ballast should support relatively heavier vehicle loads compared with its self-weight. For such a reason, actual dynamic response of the bridge is considerably differing with normal prediction because additional masses added from vehicle to a bridge have an effect on the dynamic characteristics of the bridge. These differences affect to the estimation of a natural frequency change that adopted for one of the evaluation technique of strength decrease, and these make trouble to the analysis of a natural frequency from the field test data that measured at the bridge subjected to a running vehicle. In this study, classification of mass participation ratio for each component of open deck plate girder bridge without ballast and the comparison according to the change of vibration characteristics for the case of subjected to a running vehicle were accomplished.

• Steel and Composite Structures
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• v.20 no.2
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• pp.413-429
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• 2016

A theoretical method to predict the interfacial stresses in the adhesive layer of reinforced concrete beams strengthened with externally bonded carbon fiber-reinforced polymer (CFRP) plate is presented. The analysis provides efficient calculations for both shear and normal interfacial stresses in reinforced concrete beams strengthened with composite plates, and accounts for various effects of Poisson's ratio and Young's modulus of adhesive. Such interfacial stresses play a fundamental role in the mechanics of plated beams, because they can produce a sudden and premature failure. The analysis is based on equilibrium and deformations compatibility approach developed by Tounsi. In the present theoretical analysis, the adherend shear deformations are taken into account by assuming a parabolic shear stress through the thickness of both the reinforced concrete beam and bonded plate. The paper is concluded with a summary and recommendations for the design of the strengthened beam.

• Journal of Institute of Convergence Technology
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• v.7 no.2
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• pp.1-5
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• 2017

The rotating electrodynamic wheel over a conductive plate produces thrust force as well as normal force. Specially, separating the conductive plate and spacing apart each part, the lateral stability of the rotating wheel is guaranteed due to the restoring force into neutral position. In this paper, the force characteristics of the electrodynamic wheel rotating over the conductive plate is analyzed using the finite element tool. First, the dominant parameters are identified considering the geometric configuration and the operating condition. And the sensitivity for the parameter deviation is quantified for the high force density. The above topology can be applied as an actuating principle for inter-city train as well as contact-free transfer device.

• Journal of the Korean Society of Visualization
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• v.16 no.3
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• pp.16-25
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• 2018

PIV experiments were carried out to visualize the velocity distribution of the sweeping jet impinging onto a flat plate and kinematic behavior of the jet from the fluidic oscillator. Two parameters such as four different Re cases and four different jet-to-wall distances were examined. Time-resolved two dimensional PIV measurements were performed for both streamwise and normal planes respect to the jet axis. Ensemble averaged and phase averaged velocity fields were obtained for the tested range of parameters. The sweeping frequency of the jet increases linearly with increase of Re. The kinetic energy of the sweeping jet decreases as the distance from the jet to the impinging plate increases. In addition, turbulence flow is generated due to the swinging motion of sweeping jet, and various vortices such as primary and secondary vortex are observed near the impinging wall.

• Structural Engineering and Mechanics
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• v.70 no.5
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• pp.571-589
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• 2019

This paper aims to develop a quasi-3D shear deformation theory for the study of bending, buckling and free vibration responses of functionally graded (FG) sandwich thick plates. For that, in the present theory, both the components of normal deformation and shear strain are included. The displacement field of the proposed model contains undetermined integral terms and involves only four unknown functions with including stretching effect. Using Navier's technique the solution of the problem is derived for simply supported sandwich plate. Numerical results have been reported, and compared with those available in the open literature were excellent agreement was observed. Finally, a detailed parametric study is presented to demonstrate the effect of the different parameters on the flexural responses, free vibration and buckling of a simply supported sandwich plates.

• Korean Journal of Applied Biomechanics
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• v.31 no.2
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• pp.113-118
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• 2021

Objective: The purpose of this study was to investigate differences of landing strategy between people with or without chronic ankle instability (CAI) during double-leg drop landing. Method: 34 male adults participated in this study (CAI = 16, Normal = 18). Participants performed double-leg drop landing task on a 30 cm height and 20 cm horizontal distance away from the force plate. Lower Extremities Kinetic and Kinematic data were obtained using 8 motion capture cameras and 2 force plates and loading rate was calculated. Independent samples t-test were used to identify differences between groups. Results: Compared with normal group, CAI group exhibits significantly less hip internal rotation angle (CAI = 1.52±8.12, Normal = 10.63±8.44, p = 0.003), greater knee valgus angle (CAI = -6.78±5.03, Normal = -12.38 ±6.78, p = 0.011), greater ankle eversion moment (CAI = 0.0001±0.02, Normal = -0.03±0.05, p = 0.043), greater loading Rate (CAI = 32.65±15.52, Normal = 18.43±10.87, p = 0.003) on their affected limb during maximum vertical Ground Reaction Force moment. Conclusion: Our results demonstrated that CAI group exhibits compensatory movement to avoid ankle inversion during double-leg drop landing compared with normal group. Further study about how changed kinetic and kinematic affect shock absorption ability and injury risk in participants with CAI is needed.

• Journal of Korean Neurosurgical Society
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• v.54 no.4
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• pp.275-279
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• 2013

Objective : This study was designed to determine the most reliable cephalometric measurement technique in the normal population and patients with basilar invagination (BI). Methods : Twenty-two lateral radiographs of BI patients and 25 lateral cervical radiographs of the age, sex-matched normal population were selected and measured on two separate occasions by three spine surgeons using six different measurements. Statistical analysis including intraclass correlation coefficient (ICC) was carried out using the SPSS software (V. 12.0). Results : Redlund-Johnell and Modified (M)-Ranawat had a highest ICC score in both the normal and BI groups in the inter-observer study. The M-Ranawat method (0.83) had a highest ICC score in the normal group, and the Redlund-Johenll method (0.80) had a highest ICC score in the BI group in the intra-observer test. The McGregor line had a lowest ICC score and a poor ICC grade in both groups in the intra-observer study. Generally, the measurement method using the odontoid process did not produce consistent results due to inter and intra-observer differences in determining the position of the odontoid tip. Opisthion and caudal point of the occipital midline curve are somewhat ambiguous landmarks, which induce variable ICC scores. Conclusion : On the contrary to other studies, Ranawat method had a lower ICC score in the inter-observer study. C2 end-plate and C1 arch can be the most reliable anatomical landmarks.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.4
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• pp.114-120
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• 2018

Recently, the plate girder bridge is offen designed a temporary bridge for underground roadway construction have not interrupt railroad operation. The integral support plate girder bridge which have longitudinal girder and cross-girder is improved workability and reduction cost and of construction time. The cross beam of the integral support plate girder bridge has a normal box shape to distribute load on the main girde to end both side girder. In this study, On the change to the web distance of the cross box shows characteristics of related to the stresses and displacements on the flange and web plate. Afterward, the various analysis contributed to the safety improvement of crossbeam of the integral support crossbeam plate girder bridge.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1173-1174
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• 2013

• Journal of the Korean Society for Precision Engineering
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• v.24 no.9
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• pp.44-51
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• 2007

There are many methods to assemble various parts of a product, and one of them is the bolting system widely used in a industrial field due to the merits; easiness to obtain strong tightening force, simplicity of assemble or disassemble in order to repair, substitution or cleaning, and so on. But this bolting system needs attachments not to let a bolt loose and they are an important factor to cost a great deal. In this study, some equations are suggested and FE analyses are carried out to verify the cause of the bolt looseness occurring in the tightening process. And because the number of bolts in the bolting system has been decided by empirical know-how of designers in the field, safety rate in the plate type heat exchanger is often too high. Therefore the equations to decrease in quantity are suggested in consideration of the relationship between a critical shearing force acting on the screw and a normal force acting on the cooling plate by the working fluid.