• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.703-707
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• 2007

The line pressure control system for an automotive transmission in which a bleed type variable force solenoid(VFS) is applied, has been constructed and experimentally investigated. The hydraulic circuit of the system includes a line pressure control valve, a reducing valve, an accumulator, various orifices and a VFS. Static and dynamic responses of the throttle and line pressure have been monitored and discussed for various test conditions.

• Journal of Korean Association for Spatial Structures
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• v.20 no.4
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• pp.45-52
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• 2020

In this study, performance experiments were performed on the shape of steel dampers that affect the rocking behavior. Three types of strut shapes of SI type, SV type and SS type were considered as experimental variables. As a result of the experiment, the capacity to resist the moment and drift ratio according to the strut shape of the steel damper was evaluated as very close. Finally, it was evaluated that the SV type steel damper has stable deformation and energy dissipation capability. As a result of the evaluation of the proposed damper transmission force, it is considered that the damper transmission force is evaluated larger than the applied horizontal force, and it is necessary to supplement it.

• Transactions of The Korea Fluid Power Systems Society
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• v.1 no.2
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• pp.20-25
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• 2004

In this study, a position control characteristics of pneumatic cylinder with transmission line is analyzed. Dynamic characteristics of transmission line using compressible fluid is changed by the flowing stiles of the fluid the diameter and the length of the line. But, the effect of the change of dynamic characteristics of transmission line by the flowing states on the position control characteristics can be neglected because of the friction force of the pneumatic cylinder. So, We assume that the position control characteristics is affected by the diameter and length of the transmission line. The experimental results according to the change of parameter of the transmission line show that the relation between the parameter of the transmission line and the position control characteristics of pneumatic cylinder driving system with the transmission line.

• Journal of the Society of Naval Architects of Korea
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• v.35 no.2
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• pp.38-50
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• 1998

In order to understand the characteristics of floating breakwaters we planned series of experimental and numerical investigations and completed the first stage which is the experiment with fred pontoons near the free surface. As controlling parameters the draft and breadth of pontoon were varied and the wave frequency and steepness were also varied. Wave transmission and forces exiled on the breakwater were experimentally investigated and compared with the results computed based on linear potential theory. Discussions made are on the effect of draft and wave length on the wave transmission and force in fixed pontoon case. The predicted and measured results show quantitatively good agreement both in forces and transmission coefficient. The effect of separation distance between two pontoons on the wave transmission and force in array case is also examined.

• Structural Engineering and Mechanics
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• v.71 no.3
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• pp.291-303
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• 2019

In the paper the analysis of natural vibrations of the transmission line with use of spectral elements and the laboratory experiments is performed. The purpose of the investigation is to analyze the natural vibrations of the transmission line and compare with the results obtained in the numerical simulations. Particular attention is paid to the hysteretic and aerodynamic damping analysis. Sensitivity of the wave number is performed for changing of the tension force, as well as for the different damping parameters. The numerical model is made using the Spectral Element Method. In the spectral model, for various parameters of stiffness, damping and tension force, the system response is checked and compared with the results of the accelerations obtained in the measurements. A frequency response functions (FRF) are calculated. The credibility of the model is assessed through a validation process carried out by comparing graphical plots of FRF and time history analysis and numerical values expressing differences in acceleration amplitude (MSG), phase angle differences (PSG) and differences in acceleration and phase angle total (CSG) values. The next aspect constituting the purpose of this paper is to present the wide possibilities of modelling and simulation of slender conductors using the Spectral Element Method. The obtained results show good accuracy in the range of both experimental measurements as well as simulation analysis. The paper emphasizes the ease with which the sensitivity of the conductor and its response to changes in density of spectral mesh division, tensile strength or material damping can be studied.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.6 s.249
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• pp.631-636
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• 2006

In this study, a model of pneumatic cylinder position control system considering dynamic characteristics of transmission line is proposed. The transfer characteristics of transmission line are assumed to be second order transfer function because the effect of resonance characteristics of transmission line under high frequency range can be neglected by the friction force and low pass characteristics of the pneumatic cylinder driving system. Therefore, the position control system including transmission line can be modeled by using a model of pneumatic cylinder driving system and the model of transmission line. The effectiveness of the proposed model is proved by comparison of simulation results using proposed model with experimental results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.457-467
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• 2004

Wave Transmission analysis is one of methods for power transmission and reflection coefficients in coupled infinite structures. This paper focuses the wave transmission analysis of point coupled structures among semi-infinite beams and infinite thin plates considering all kinds of waves. It is supposed that the junction through the beams and plates is an identical spot and no point of contact exist except the spot. The boundary conditions are applied at the spot for continuities of 6 DOF displacements and 6 DOF force equilibriums, and then wave fields are obtained in the coupled structures. Since wave components in plate field are simplified using asymptotic expressions of Henkel functions, the displacements and forces at the plate junction can be simply expressed with magnitudes of the wave components. The wave fields according to incident waves gives the power transmission coefficients in beam/plate point coupled structures. For both coupled structures with a beam vertically and obliquely joined to a plate, power transmission analysis is performed and the analysis results are compared and examined.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.10
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• pp.851-856
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• 2015

This study aimed to develop a sensory feedback system which could measure force and temperature for the user of myoelectric prosthetic hands. The Sensory measurement module consisted of a force sensing resistor to measure forces and non-contact infrared temperature sensor. These sensors were attached on the fingertips of the myoelectric prosthetic hand. The module was validated by using standard weights corresponding to external force and a Peltier module. Sensory transmission module consisted of four vibration motors. Eight vibration patterns were generated by combining motion of each vibration motor and were dependent on kinds and/or magnitude. The module was verified by using standard weigts and water at varying temperatures. There were correlations of force and temperature between the sensory measurement module and standard weight and water. Additionally, exact vibration patterns were generated, indicating the efficacy of the sensory feedback system for the myoelectric prosthetic hand.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.327-330
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• 2000

The scanning Maxwell-stress microscopy (SMM) is a dynamic noncontact electric force microscopy that allows simultaneous access to the electrical properties of molecular system such as surface potential, surface charge, dielectric constant and conductivity along with the topography. The Scanning near-field optical / atomic force microscopy (SNOAM) is a new tool for surface imaging which was introduced as one application of the atomic force microscope (AFM). Operated with non-contact forces between the optical fiber and sample as well as equipped with the piezoscanners, the instrument reports on surface topology without damaging or modifying the surface for measuring of optical characteristic in the films. We report our recent results of its application to nanoscopic study of domain structures and electrical functionality in organic thin films by SMM. Furthermore, we have illustrated the SNOAM image in obtaining the merocyanine dye films as well as the optical image.

• International Journal of Precision Engineering and Manufacturing
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• v.2 no.4
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• pp.5-11
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• 2001

Vibration and noise of gears is doc to the transmission error and the vibration exciting force caused by the periodically alternating tooth stiffness. Transmission error is the rotation delay between driving and driven gear caused by manufacturing error, alignment error in assembly and so on. Tooth stiffness changes with the proceeding mesh of teeth. The purpose of this study is to develop how to calculate simultaneously the optimum amounts of tooth profile modification. end relief and crowning by minimizing the vibration exciting force of helical gears. We estimate the vibration exciting force by the meshing analysis of gears. Formulated constraints of this problem consist of contact ratio and strengths of gear teeth such as tooth bending strength, surface durability, and scoring. ADS(Automated Design Synthesis) is used as an optimization tool. We also investigate the relation between the aspect ratio and the optimum values of tooth modification. The proposed method can calculate the optimum amount of tooth modification automatically and is expected to be practically useful to resolve the problem of vibration of helical gears.