• Journal of KSNVE
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• v.8 no.2
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• pp.297-305
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• 1998

The finite element method is used for the study of the eigenvalue problems of partially fixed end beams with intermediate elastic supports. The elastic critical loads and natural frquencies of the beams are investigated by changing the numbers of elastic supports and their stiffness, and also by changing Kinney's fixity factor, $f_a$. The relationship between two eigenvalues is established by calculating the corresponding values of $(w/w_n)^2$ through changing $(P/P_{cr})$ values. The results of this study are as follows : (1) The elastic critical loads and natural frequencies of beams increase with increases in Kinney's fixity factor, $f_a$ and with the increased numbers of intermediate elastic supports. (2) The relationship between elastic critical loads and the natural frequencies of partially fixed end beams with intermediated elastic supports is $P/P_{cr} + (w/w_n)^2/ = 1$ without regard to Kinney's fixity factor, the stiffness of elastic supports, or the number of elastic supports.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.301-306
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• 2016

In bridge performance assessments, a new load carrying capacity evaluation model of simple bridges was proposed, which is based on the developed simple support impact factor spectrum. In this paper, a conservative assumption that the inner span with the both ends fixed boundary condition is ideal for applying the impact factor response spectrum for continuous bridges. The impact factor response spectrum has been proposed based on this assumption. The response spectrum by comparing the numerical analysis result and actual measurement data verified the applicability. The analysis was loading the moving load of DB-24 in a six-span continuous bridge, which was the same as the actual measurement data, the dynamic response was measured in the fourth span. The frequency of the bridge was obtained by FFT on the acceleration response and the span-frequency of sample bridge was calculated by the frequency. The impact factor of the sample bridge was determined by applying the span-frequency of the bridge to the proposed response spectrum; it was similar to the result of comparing the actual measured impact factor. Therefore, the method using the impact factor response spectrum based on the frequency response of both ends-fixed beam was found to be applicable to an actual continuous bridge.

• Journal of Welding and Joining
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• v.1 no.1
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• pp.37-46
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• 1983

This paper describes a study of fillet welded joint stressed perpendicular to the weld line. The finite element method was used to determine the stress intensity factor for cruciform joint at weld toe and root cracks according to variation of H/Tp, weld angle and main plate thickness. But, in this study, weld angle was fixed at 45.deg., since the variation of weld angle affect the stress intensity factor little, also main plate thickness was fixed. Pulsating tension fatigue test was done at the second phase of experiment. The work using the concepts of the fracture mechanics on the stable crack growth, was in the correlation of the experimental fatigue stress-life behavior because the fatigue behaviors of various joint geometries are related to the stress intensity factors calculated by F.E.M. analysis. Main results obtained are summarized as follows. 1) According to the propagation of toe crack, the variation of the stress intensity factor at root crack is obvious as H/Tp is smaller. 2) According to the propagation of root cracks, the change of the stress intensity factor of the toe is very large with propagation of root crack. 3) The calculation formula of the stress intensity factor of crack propagation at the root crack was obtained. 4) The calculation formula of the stress intensity factor at the toe cracks was obtained in similar manner. 5) From the results of experiment, the velocity of fatigue crack propagation at the weld toe and root was estimated.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.223-226
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• 2007

In current specification, modification factor(B) for web-tapered beam is used to account for the stress gradient and the restraining effect for adjacent spans. However, because these effects are considered together in modification factor, this paper revaluate the accuracy of the modification factor used in current specification. Also this paper investigate the flexural torsional buckling strength of laterally fixed thin-walled arch with doubly symmetric section using the analytical and numerical method. From this investigate the concept of effective length to consider the out-of-plane boundary condition for straight column or beam is not applicate for the flexural-torsional buckling of laterally fixed arches.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.9
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• pp.1793-1801
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• 2015

In a recent work, kernel recursive least-squares tracker (KRLS-T) algorithm has been proposed. It is capable of tracking in non-stationary environments using a forgetting mechanism built on a Bayesian framework. The forgetting mechanism in KRLS-T is implemented by a fixed forgetting factor. In practice, however, we frequently meet that the fixed forgetting factor cannot handle time-varying system effectively. In this paper we propose a new KRLS-T with a variable forgetting factor. Experimental results show that proposed algorithm can handle time-varying system more effectively than the KRLS-T.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5B
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• pp.515-524
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• 2008

An estimation of reliable probability precipitation is one of the most important processes for reasonable hydrologic structure design. A probability precipitation has been calculated by frequency analysis using annual maximum rainfall series on the each duration among the observed rainfall data. Annual maximum rainfall series have abstracted on hourly rainfall data or daily rainfall data. So, there is necessary to proper conversion factor between the fixed and sliding durations. Therefore, in this study, conversion factors on the each duration between fixed and sliding durations have calculated using minutely data compared to hourly and daily data of 37 stations observed by Meteorological Administration in Korea. Also, regression equations were computed by regression analysis of conversion factors on the each duration. Consequently, conversion factors were used basis data for calculations of stable probability precipitation.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.297-302
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• 1999

Finite element analysis is peformed about the crack propagation in half-space due to sliding contact. The analysis is based on linear elastic fracture mechanics and stress intensity factor concept. The crack location is fixed and the friction coefficient between asperity and half-space is varied to analyze the effect of surface friction on stress Intensity factor for horizontal crack. The crack propagation direction is predicted based on the maximum range of shear and tensile stress intensity factor.

• Water for future
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• v.43 no.9
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• pp.123-129
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• 2010

• Bulletin of the Korean Mathematical Society
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• v.38 no.3
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• pp.475-486
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• 2001

In this paper we give a relationship among the Minkowski units, for all odd prime number including $\infty$, of 2-periodic knot is $S^3$, its factor knot, and the 2-component link consisting of the factor knot and the set of fixed points of the periodic action.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.1
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• pp.45-54
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• 2012

Optimization of the asymmetric trapezoidal fin with various upper lateral surface slope is made using a two-dimensional analytic method. For the fixed fin base height, the optimum heat loss, fin length and effectiveness are represented as inner fluid convection characteristic number, fin base thickness, fin base height, fin shape factor and ambient convection characteristic number. For this optimum procedure, the optimum heat loss is defined as 95% of the maximum heat loss from the fin. One of the results shows that optimum heat loss and effectiveness seems independent of the fin shape factor while optimum fin length decreases almost linearly as the fin shape factor increases.