• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.121-126
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• 2000

The attaching method of different types of structure and explanation of stress transfer mechanism are at important issue as beam having definitive factor such as the anchorage of RC main bar, the stress transfer of anchorage-end S member, RC member-anchorage, anchorage-end S member in the composite beam of S and RC member. In this study, the structural properties of composite beam according to attaching method of main bar about end RC-middle S beam were investigated in order to use them as fundamental data for the development of composite structure member. Throughout a series of study, it was shown that the proof stress of main bar - flange welding specimen is the highest and there is no difference between the deformation-properties according to attaching method of main bar.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 1999년도 추계학술발표대회 논문집
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• pp.1-4
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• 1999

The attenuation coefficients of SiC particle reinforced low-density polyethylene (LDPE) matrix composites were measured by pulse echo method and dynamic elastic measure method with varying the volume fraction of SiC particle ranged from 0% to 40% and the size of SiC particles ranged from 0.8$\mu$m to 48$\mu$m. The SiCp/LDPE composites were fabricated with the melt injection process and the fabricated composites showed almost full density above 99% up to 40vo1% SiCp reinforcements. The attenuation constant of LDPE measured by dynamic elastic constant had same result with that measured by pulse echo method, but the attenuation constant of SiCp/LDPE measured by dynamic elastic constant did not have same result with that measured by pulse echo method.

• 대한기계학회논문집
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• 제18권4호
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• pp.816-825
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• 1994

The purpose of this study is to develop the non-destructive material evaluation method of aluminum alloy base metal matrix composite(MMC) by ultrasonics. Five aluminum base MMC specimens were fabricated in which the fractional ratios of fiber were changed from 0% to 31%. Relations among acoustic properties, microstructural features and elastic constant were compared. The ultrasonic velocity method was useful for nondestructive elastic constant measurement of composite materials, since the method had as same accuracy as conventional strain measurement method. Furthermore, velocity, attenuation and backscattering behaviors for each specimen also related to fractional ratio of fiber and these relations could utilize ultrasonic non-destructive evaluation of fiber structure in MMC.

• Smart Structures and Systems
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• 제30권4호
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• pp.371-383
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• 2022

A novel impact localization method is presented based on impact induced elastic waves in sensorized composite structure subjected to temperature fluctuations. In real practices, environmental and operational conditions influence the acquired signals and consequently make the feature (particularly Time of Arrival (TOA)) extraction process, complicated and troublesome. To overcome this complication, a robust TOA estimation method is proposed based on the times in which the absolute amplitude of the signal reaches to a specific amplitude value. The presented method requires prior knowledge about the normalized wave velocity in different directions of propagation. To this aim, a finite element model of the plate was built in ABAQUS/CAE. The impact location is then highlighted by calculating an error value at different points of the structure. The efficiency of the developed impact localization technique is experimentally evaluated by dropping steel balls with different energies on a carbon fiber composite plate with different temperatures. It is demonstrated that the developed technique is able to localize impacts with different energies even in the presence of noise and temperature fluctuations.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.183-188
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• 2002

Co-cured composite materials has its own characteristics, so its thermal expansion is different each other. The selection of tool material for co-cured composite part in high temperature more over $350^{circ}F$ and 50 Psi pressure have to consider part thermal expansion, size, shape, and economic aspect in production line. So it is important choose tooling material in manufacturing composite parts. We called the tool for airplane composite parts as BAJ (Bonding Assembly Jig). Composite parts are cured on the BAJ in autoclave. BAJ have to stable at high temperature over $350^{circ}F$ and 50 Psi pressure, Considering composite parts' dimensional tolerance compare to heat up in autoclave. This paper come from the results of the experiment at the composite parts production line and review other aircraft company's method for tooling This is for the engineer engaged in composite parts manufacturing.

• 복합신소재구조학회지
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• 제6권1호
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• pp.33-36
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• 2015

• 복합신소재구조학회지
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• 제4권1호
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• pp.9-13
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• 2013

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.777-778
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• 2012

• 대한토목학회논문집
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• 제33권2호
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• pp.423-431
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• 2013

k-factor법은 합성교량의 설계에서 부정정 응력을 산정하는 방법으로 널리 사용되고 있다. 이 방법의 적정성을 평가하기 위하여 2경간 연속 강합성거더에 대하여 등가하중법과 비교하였다. k-factor법은 크리프에 대해서는 강재응력을 과소평가하고, 부모멘트 구간에서는 응력의 방향을 반대로 산정하며, 건조수축이나 온도차에 대해서는 단면변화를 고려하지 못하는 것을 확인하였다. 이 논문에서는 k-factor법의 정확성을 개선하면서, 계산의 편리성은 유지할 수 있는 j-factor법을 제안하였고, 그 효과를 2경간 연속 강합성거더에 적용하여 검증하였다.

• 보건행정학회지
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• 제3권1호
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• pp.84-101
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• 1993

The current method of rate adjustment is based on the evaluation of the financial performance of hospitals. The method has the disadvantages such as too complicated, expensive process as well as low reliability due to small sample size. This study, therefore, develops a new model for the rate adjustment with the use of the composite index. In addition to that, it examines the validity of the model by comparing the result of the new method with that of the conventional method. The idea of the new model comes from the Medicare Economic Index(MEI) on which physician fees for the Medicare patients are adjusted periodically in the United States. Medical costs are classified into three groups : labor costs, materials and other expenses. Labor costs are subdivided into physicians and other personnels. Materials are subdivided into drugs and others. Other expenses are subdivided into 5 items. Macro economic indices are selected for each cost item in order to reflect the cost inflation during the specific period. Then the composite index which integrate all items according to the ration of each item in the total costs is calculated. The result from the application of empirical data to the new model is very similar to that of the current method. Furthermore, this method is very simple and also to easy to get social concensus. This model can be replaced the current method based on the analysis of the financial performance for the adjustment of medical fees.