• Journal of Advanced Marine Engineering and Technology
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• v.26 no.6
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• pp.688-694
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• 2002

Several methods were developed for on-line measuring oil consumption in gasoline engine using an oil consumption meter. The oil consumption meter indicates the oil quantity by real-time-measuring the oil level in the sump. In order to measure the oil consumption, the oil consumption meter proposed in this paper requires shorter time, less additional procedures, and shows better results than the traditional drain method. Under steady-state engine-operating conditions, the results obtained through the regression or the difference method show an good agreement with those through the drain method. Under transient engine-operating conditions, on the other hand, good results can be obtained through the reference method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.3
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• pp.185-196
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• 2006

Fracture toughness is a material property for crack initiation and propagation in fracture mechanics. For mode I fracture toughness measurement in concrete, RILEM committees 89-FMT proposed three-point bend tests based on the two-parameter fracture model. But, there is no proposed test method as a standard for mixed mode test for now. And RILEM three-point bend test procedure is complicate. Therefore, in this study, brazilian disks of various size were designed as the concrete with a similar specified concrete strength and maximum size of coarse aggregate($G_{max}$) were respectively 20mm and 40mm. And mode I fracture toughness of brazilian disks was compared with that of RILEM three-point bend test. As a result, it was suggested appropriate size(thickness, diameter) and notch length ratio of brazilan disk on the $G_{max}$. And it was verified that stress intensity factors for mixed mode can be easily calculated with the disk specimen. Stress intensity factors of a concrete brazilian disk were evaluated with finite element analysis and five terms approximation for comparison.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.8
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• pp.1322-1331
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• 1997

A method of strength evaluation applying fracture mechanics in the adhesively bonded joints of Al/Steel dissimilar materials was investigated in this paper. Various shapes of adhesively bonded Al/Steel scarf joints focussing on fracture criterion of mixed mode crack were prepared for the static tests. Also, stress intensity factors of the interface cracks in adhesively bonded joints of Al/Steel dissimilar materials were analyzed with 2-dimensional elastic program of boundary element method(BEM), and the experiment of fracture toughness were carried out under various mixed mode conditions. From the results, the fracture criterion and method of strength evaluation by the fracture toughness in adhesively bonded joints of Al/Steel dissimilar materials were proposed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.254-260
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• 1998

Application of bonded dissimilar materials in various industries are increasing. When these materials are used in structures, it needs to investigate strength evolution applying fracture mechanics. Al/Epoxy bonded dissimilar materials with an interface crack and an interface crack emanating from an edge semicircular hole were prepared for the static tests so that experiment of fracture toughness were carried out. Stress intensity factors of interface cracks in bonded dissimilar materials were computed with boundary element method(BEM) and the fracture criterion of mixed mode crack were analyzed. From the results, the fracture criterion and the method of strength evolution by the fracture toughness in Al/Epoxy bonded dissimilar materials were proposed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.6
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• pp.907-915
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• 2001

Application of bonded dissimilar materials in many industries are increasing. When these materials are to be used in structures, it needs to evaluate the failure strength applying fracture mechanics. Al/Epoxy bonded dissimilar materials with an interface crack and an interface crack emanating from an edge semicircular hole were prepared, experiment of fracture toughness were carried out. Stress intensity factors of interface cracks in bonded dissimilar materials were computed with boundary element method(BEM) and the fracture criteria of mixed mode crack were analyzed. From the results, the fracture criteria and the method of strength evaluation by the fracture toughness in Al/Epoxy bonded dissimilar materials were proposed.

• Computational Structural Engineering
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• v.3 no.4
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• pp.123-132
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• 1990

In current practice of earthquake resistant design the equivalent lateral force procedure is widely used because of its simplicity and convenience. But the equivalent lateral force procedure is derived based on the assumptions that the dynamic behavior of the structure is governed primarily by the fundamental vibration mode and the effect of higher modes is included in an approximate manner. Therefore the prediction of dynamic responses of structures using the equivalent lateral force procedure is not reliable when the effect of higher vibration modes on the dynamic behavior is significant. In this study, design seismic load which can reflect the effect of higher vibration modes is proposed from the point of view of proper assessment of story shears which have the major influence on the design moment of beams and columns. To evaluate the effect of higher modes, differences between the story force based on the equivalent lateral force procedure specified in current earthquake resistance building code and the one based on modal analysis using design spectrum analysis are examined. From these results an improved design seismic load for the equivalent lateral force procedure which can reflect the effect of higher vibration modes are proposed.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.455-457
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• 2006

The mutual relations and equivalence between the boundary conditions for electromagnetic waves are discussed in terms of a waveguide step. In order to verify our approach, the reflection characteristics of a rectangular waveguide step are compared with respect to the boundary conditions. The characteristics of a rectangular waveguide step are analyzed with a mode-matching technique. In order to verify our approach, convergence behaviors and electromagnetic distributions are shown.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.5
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• pp.63-72
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• 2001

In this paper, to satisfy the safety and economy immediately, we assume the center of lateral load in case the dynamic motion of the torsionally unbalanced structure is transformed into the static lateral load using modal analysis and proposes a method to control the design eccentricity in order to make the center of lateral load coincide with the center of strength. And when the structure is designed by proposed method, it is shown that the structure designed by proposed method does not demand excessive additional ductility in comparison with the structure designed by provisions of other seismic building code.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.2
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• pp.17-29
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• 1997

Single-mode spectral analysis method is usually applied to a small-scale bridges with the simple geometric shape and uses only fundamental period to estimate the elastic earthquake forces and the displacements of the substructure. On the other hand, multi-mode spectral analysis method may be used instead if the possibilities of potential damage are developed when considering significance, scale, and geometric shape of briages. Since the dynamic responses of bridge can be significantly different depending on the modeling techniques for the restraint and support conditions etc, it may be misled to the unexpected results. In this study the dynamic analysis program which can model and analyze the bridge as a two- or three-dimensional framed structure is developed and verified with the results of other reliable program. Using this program together with the post processor, the designer can easily and readily obtain the reponses(moments, base shears, and displacements)of bridges necessary to design purpose. And further from the analysis results according to the variations of type, scale, and restraint and supprot conditions of bridges including sectional properties, applications of the effective and desirable seismic design are presented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.8
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• pp.650-655
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• 2013

For the DC-free encoding of source data, the Guided Scrambling (GS) technique is widely used as multi-mode coding in the optical data storage system. For DC-suppression GS coding in the holographic data storage system, the conservative array and balanced coding criteria are proposed. In this paper, equivalent integer programming models are developed to determine the optimal control bits for the minimum digital sum value (MDSV), conservative array, and balanced coding criteria. Using the proposed integer programming models, we compare the performance of GS encoding for the various combination of control bit/array sizes and scrambling polynomials.