• 한국강구조학회 논문집
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• 제9권1호통권30호
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• pp.37-49
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• 1997

The buckling behavior of the web of steel girders are largely dependent on the size and the location of stiffeners and the restraining effect of top and bottom flanges. Elastic and inelastic buckling analyses based or the Spline Finite Strip Method were executed to study the stiffening effect of the longitudinal stiffener on the web of box girders and to find how the top and bottom flanges had effects on the web, where geometric boundary conditions were limited by both hinged, both fixed and the flange sections. The basic assumption for the longitudinal end boundary conditions was that the vertical stiffeners had the rigidity enough to force nil deflection line on the web panel so that the junction line between web and vertical stiffener was assumed to be hinged boundary conditions. The provisions on the longitudinal stiffener of the plate and box girders of the Korean Standard Highway Bridge Specifications(1995) and AASHTO Specifications(1994 LRFD) were compared with the results obtained numerically for the various longitudinal stiffener size of box girders. Simple equations and design curves for the longitudinal stiffener of the web were proposed for the practical use.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.120-127
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• 1998

This paper deals with the dynamic responses of the multi-span continuous bridge with longitudinal shear keys. It is motivated by a need to understand the effects of longitudinal shear keys which may be used for the reduction of the longitudinal seismic force in continuous bridges. The results show that (1) The force reduction of fixed pier is proportional to the ratio of gap size and elastic maximum displacement of the bridges without shear keys ; (2) The thermal movement has little effect on the response of the continuous bridges with shear keys. Also the simplified equation is proposed to calculate the maximum response of the continuous bridges with longitudinal shear keys. The equation requires only the elastic analysis results of the bridge and the gap size between superstructure and shear keys.

• 패션비즈니스
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• 제6권6호
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• pp.78-88
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• 2002

The purpose of this study is to provide for some basic data useful to production of the apparels fit and measured well for the Chinese men. For this purpose, 389 men aged between 20 and 49 and living in Beijing and Shanghai, China were sampled to be measured for their constitutions. Then, their constitutions were classified and thereupon, according to the Men's Wear Specifications (GB/T 1335.1-1997), National Standards of People's Republic of China. The collected data were statistically processed using SAS 6.12 for technical statistical analysis, correlation analysis, factor analysis, group-wise analysis. The results of this study can be summarized as follows; 1. As a result of the factor analysis aiming to determine Chinese men's constitutional components, five components could be identified: constitutional obesity, lateral body size, longitudinal body size, shoulder and back width, and shoulder drooping. 2. As a result of classifying Chinese men's constitutions according to drop measurements, four types could be identified. Y type had the lowest obesity and the highest longitudinal body size. A type had a lower obesity and had an average longitudinal body size. B Type had the second highest obesity, the smallest longitudinal body size and shoulders/back width. C Type had the highest obesity, upper body length and shoulders/back width. 3. In terms of distribution, 'B' type (39.10%) of the sample, followed by 'A' type (29.26%), 'C' type (19.95%) and 'Y' type (11.70%). In all, the results of this study suggests that 'B' type represents the Chinese men in contrast with GB specifying that 'A' type represents the Chinese men. On the other hand, Beijing region was dominated most by 'B' type (37.06%), followed by 'A' type (28.82%), 'C' type (22.35%) and 'Y' type (11.76%), while Shanghai region was dominated most by 'B' type (41.13%), followed by 'A' type (31.21%), 'C' type (19.15%) and 'Y' type (8.51%).

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.661-667
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• 2002

Welding-induced buckling distortion is one of the most problematic concerns in both design and fabrication of welded thin-plate structures. This paper deals with experimental and numerical results of the welding-induced longitudinal and/or buckling distortion occurring in welding of 6mm-thick AH36 high strength steel plates. Effects of the heat input and the plate size on the distortion were experimentally evaluated for square plates. Bead-on-plate welding was performed with the submerged arc welding process along the middle line of plate specimens. Experimental results showed that the longitudinal distortion made a single curvature in the plate, and the distortion magnitude along the weld centerline was proportional to the heat input and the plate size. The experimental results were used to examine the validity of the numerical simulation procedure for welding-induced distortion where the longitudinal distortion mode and magnitude were numerically quantified. Three-dimensional, large deformation, welding simulations were performed for selected weld models. Numerical results of the distortion mode and magnitude were in a good agreement with experimental ones. Depending on the presence of halting the distortion growth during the cooling cycle of welding, the condition discriminating buckling distortion from longitudinal distortion was established. Eigenvalue analyses were performed to check the buckling instability of tested plates with different sizes subjected to different heat inputs. The perturbation load pattern for the analysis was extracted from longitudinal inherent strain distributions. Critical buckling curve from the eigenvalue analyses revealed that the buckling instability is manifested when plate size or heat input increases.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.969-974
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• 2004

Although guided-waves are very efficient for long-range nondestructive damage inspection, it is not easy to extract meaningful pulses of small magnitude out of noisy signals. The ultimate goal of this research is to develop an efficient signal processing technique for the current guided-wave technology. The specific contribution of this investigation towards achieving this goal, a two-stage Gabor pulse-based matching pursuit algorithm is proposed : rough approximations with a set for predetermined parameters characterizing the Gabor pulse and fine adjustments of the parameters by optimization. The parameters estimated from the measured signal are then used to assess not only the location but also the size of a crack existing in a rod. To validate the effectiveness of the proposed method, the longitudinal wave-based damage detection in rods is considered. To estimate the crack size, Love's theory for the dispersion of longitudinal waves is employed.

• Communications for Statistical Applications and Methods
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• 제27권3호
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• pp.301-311
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• 2020

Schwarz's Bayesian information criterion (BIC) is one of the most popular criteria for model selection, that was derived under the assumption of independent and identical distribution. For correlated data in longitudinal studies, Jones (Statistics in Medicine, 30, 3050-3056, 2011) modified the BIC to select the best linear mixed effects model based on the effective sample size where the number of parameters in covariance structure was not considered. In this paper, we propose an extended Jones' modified BIC by considering covariance parameters. We conducted simulation studies under a variety of parameter configurations for linear mixed effects models. Our simulation study indicates that our proposed BIC performs better in model selection than Schwarz's BIC and Jones' modified BIC do in most scenarios. We also illustrate an example of smoking data using a longitudinal cohort of cancer patients.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.259-262
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• 2000

In this study, 3.1$\times$3.7$\times$0.365 $\textrm{mm}^2$ model of thickness-longitudinal vibration mode VHF ceramic resonator with (Pb,Ca)(Co,W,Ti)O$_3$ ceramics was simulated by ANSYS according to the electrode size. With the variations of electrode size of the model, fundamental and the third overtone dynamic ratio was investigated. At the ratio of electrode to model thickness(1/t) 2.5, third overtone dynamic ratio was largely increased. That model is suitable for 20 MHz resonator.

• 대한건축학회논문집:구조계
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• 제36권2호
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• pp.117-126
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• 2020

The main objective of this experimental study is to investigate shear strength of reinforced concrete beams according to longitudinal reinforcement ratio (ρ) and size effect. In order to find out the shear strength according to the tensile reinforcement ratio, in particular, the main variables are 100%, 75% and 50% of ρ=0.01 which is widely used in construction field. A total of twelve RC beams were tested under 4-point loading conditions. In addition to the existing proposal equations, the theoretical values such as KBC and ACI equations are compared with the experimental data. Through this analysis, this study is designed to provide more reasonable equations for shear design of reinforced concrete beams. When shear reinforcement bar spacing of nine specimens (R^*-1, R^*-2, and R^*-3 series) fixed as d/s=2.0 and three specimens of R^*-4 series fixed as d/s=1.5 are compared, the shear strength of two groups showed similar values. As a result, the current standard of d/s=2.0 for shear reinforcement bar spacing may be somewhat alleviated.

• 콘크리트학회논문집
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• 제22권2호
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• pp.263-271
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• 2010

이 연구는 국내에서 생산되고 있는 철근이 반복하중을 받는 경우의 파괴 특성에 대한 검증을 목적으로 한다. 이 논문은 철근콘크리트 하부구조(파일과 교각)에 배근된 축방향 철근에 대한 저주파 피로 거동을 다루었다. 전체 81개의 철근 실험체에 대하여 변형률 진폭에 따른 반복 축방향 변형률 제어 방식으로 저주파 피로 실험을 수행하였다. 실험 변수는 인장변형률과 압축변형률의 비율, 축방향 철근의 항복강도, 철근지름에 대한 철근길이의 비율, 철근의 크기와 변형률 진폭으로 선택하였다. 이 논문에서 실험 결과에 따른 저주파 피로 거동과 저주파 피로 수명을 분석하였다.

• 한국안전학회지
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• 제13권4호
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• pp.292-299
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• 1998

본 연구에서는 철근콘크리트 보의 휨 및 전단거동에 대한 크기효과를 실험적으로 연구하고 그 결과를 다른 연구와 비교했다. 주철근비는 같고 크기가 다른 부재를 하나의 시리즈로 실험을 했으며, 주요 실험변수는 주철근비와 부재의 상대높이이다. 휨 및 전단강도의 크기효과는 주철근비에 따라 유효높이가 일정하게 변하는 부재를 실험함으로써 측정했다. 본 연구의 결과를 살펴보면 철관콘크리트 보의 휨 및 전단에 대한 크기효과는 상당히 크다는 사실을 알았다. 철근콘크리트 부재의 휨 및 전단강도에 대한 예측식을 제안했으며, 실험치와 비교적 잘 일치했다. 따라서 본 연구의 결과는 철근콘크리트 구조물의 보다 정밀한 해석 및 설계에 유용할 것으로 기대된다.