• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.04b
• /
• pp.601-606
• /
• 1998

In recent years, strengthening by steel plate, carbon fiber sheets, and carbon fiber laminate in spotlighted in order to repair and rehabilitation of R/C slabs. In this study, 3 method of rehabilitation are analyzed from the tests. Test parameters are the width of cracks, the method of repair and rehabilitation, the magnitude of pre-load. Deflection, failure load, strains of reinforcing bar, strains of sheet and plates are measured during tests. The failure mode and separption load analyzed from these measured data.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.2
• /
• pp.225-233
• /
• 2002

The flexural vibration characteristics of a sandwich beam system with a partially inserted viscoelastic layer have been quantitatively studied using a finite element analysis in combination with a sine-sweep test. Antisymmetric mode shapes of the flexural vibration were visualized by the holographic interferometry and agreed with those calculated by the finite element simulation. Effects of the beam thickness as well as the length and thickness of partial viscoelastic layers on the system loss factor(η$\_$s/) and resonant frequency($\omega$$\_$r/) were significantly large fur the symmetric and antisymmetric modes of the beam system.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.314-317
• /
• 2002

The sloshing phenomenon sometimes happens to be occurred in the liquid storage tank due to the unexpected and/or inevitable vibrating conditions and may result in severe effects on the structural stability. This study deals with the development of experimental techniques for the evaluation of sloshing behavior in the liquid storage tank and for the identification of natural frequencies and mode shapes by varying with various vibrating conditions. In addition, suitable method is suggested to minimize the sloshing effect on the liquid storage tank and its validity is experimentally investigate d.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.6
• /
• pp.104-108
• /
• 2002

Sandwich plate structure is widely used in various fields of industry due to its excellent strength and stiffness compared with weight. In this paper, the mechanical behavior of sandwich plate structure with honeycomb core considering buckling is investigated in detail. The focus of the analysis is to evaluate strength and stiffness of the plate structure with critical stress, natural frequency, and mode shapes. The results of this investigation are obtained from detailed finite element analysis for various parameters, such as length, height ratio, and thickness ratio of honeycomb core.

• Journal of KSNVE
• /
• v.8 no.6
• /
• pp.1172-1180
• /
• 1998

Elastic wave scattering from an acoustically rigid or soft object is studied and compared with the acoustic wave scattering. The behavior of phases as well as magnitudes of partial waves and their total summation of scattered wave are numerically analyzed and discussed. The effect of mode conversion, which occurs between longitudinal and transversal waves in elastic wave scattering. on the magnitudes and phases of scattered waves is identified.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2006.11a
• /
• pp.865-868
• /
• 2006

In this paper, a dynamic behavior(natural frequency) of a cracked simply supported pipe conveying fluid is presented. In addition, an analysis of the flutter and buckling instability of a cracked pipe conveying fluid due to the coupled mode (modes combined) is presented. Based on the Euler-Bernouli beam theory, the equation of motion can be constructed by using the Lagrange's equation. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments. The stiffness of the spring depends on the crack severity and the geometry of the cracked section. The crack is assumed to be in the first mode of fracture and to be always opened during the vibrations. This study will contribute to the safety test and stability estimation of structures of a cracked pipe conveying fluid.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.1008-1016
• /
• 2007

The purpose of this paper is to investigate the Natural Frequency behavior characteristic of Wind Turbine Tower model, and calculated the stress values of thrust load, wave load, wind load, current load, and gravity load. The offshore Jacket Type Tower which was installed in Vitenam South China Sea is used for the study. Natural frequency and mode shape are calculated with commercial program using the measured vibration. The finite element analysis is performed with commercial F.E.M program(ANSYS) on the basis of the natural frequency and mode shape.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.5
• /
• pp.1036-1042
• /
• 2011

This paper presents an algorithm that conducts automatic memory scrubbing operated by dedicated hardwares. The proposed algorithm is designed so that it can scrub entire memory in a given scrub period, while minimally affecting the execution of flight softwares. The scrub controller is constructed in a form of state machines, which have two execution modes - normal mode and burst mode. The deadline event generator and period tick generator are designed in a separate way to support the behavior of the scrub controller. The proposed controller is implemented in VHDL code to validate its applicability. A simple version of the controller is also applied to mass memory modules used in STSAT-3.

• Journal of Information Display
• /
• v.5 no.3
• /
• pp.14-17
• /
• 2004

We have developed a new type of transflective liquid crystal display (LCD) with a single cell gap and a single LC mode. In our transflective configuration, a single LC mode of a 60$^{\circ}$ twisted nematic LC was used for both transmissive and reflective applications. The measured electro-optic characteristics of our transflective LC cell agree well with numerical simulation results. Moreover, the transmittance was found to show similar behavior to the reflectance.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.27 no.5
• /
• pp.793-801
• /
• 1990

A single mode fiber-optic Mach-Zehnder interferometer for the measurement of strain is described. A fiber-optic strain gauge with great resolution and wide measurement range is realized. In order to varify the dynamic response, the measurements of strain below 1涅 with frequency range 5-50Hz are compared with a semiconductor strain gauge. We report theoretical evaluation for mechanical analysis, PZT-plate, the phase change in a fiber-optic strain gauge and a semiconductor strain gauge. The dynamical characteristics of a fiber-optic strain gauge and a semiconductor strain gauge output siganl show equivalent behavior. This result is shown in very good usage as the dynamical measurement of the low strain below 1涅 by this system.