• Title/Summary/Keyword: 직선 보 요소

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A Study on the Distortional Analysis of Curved Steel Box Girders and Determination of Diaphragm Spacing (곡선 강상자형 거더의 뒤틀림 해석 및 격벽간격산정)

  • Koo, Min Se;Yoon, Wo Hyun;Lee, Ho Kyoung;Kim, Dae Hong
    • Journal of Korean Society of Steel Construction
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    • v.15 no.2
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    • pp.125-135
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    • 2003
  • A 3-dimensional model of curved steel box girder bridges without diaphragm was presented. This model yielded results that were consistent with those of the parameter analysis using the BEF and Ritz methods. Se veralmodels with diaphragms were analyzed to estimate the appropriate diaphragm spacing. In case of 50m span, models A-10, A-20, A-30, B-10, B-20, and B-30 were found to have 5(8.3m), 7(6.25m), 8(5.5m), 4(10m), 6(7.1m), and 7(6.25m) diaphragms, respectively. In addition, a formula that presents the ratio of distortional stress to bending stresswas created from the results of the 3-dimensional FEM model analysis.

Experimental and Analytical Studies on the Non-Linear behaviors of Pre-Stressed Steel H-Beams (프리스트레스트 H형강 거더의 비선형 거동에 대한 실험적 및 이론적 연구)

  • Kim, Moon-Young;Kim, Nak-Kyung;Oh, Yong-Hwan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.32 no.6
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    • pp.359-366
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    • 2019
  • Experimental and analytical studies on the behavioral characteristics of a pre-stressed (PS) steel girder are conducted to investigate the effects of deviators on the non-linear inelastic properties of the PS system. In this regard, 4 test specimens consisting of a steel H-beam, a straight cable with eccentricity, anchorages, and deviators are built and failure tests are performed under two-point loading. In addition, in-plane elastic deformation theories for the PS system without a deviator, and with three deviators at regular intervals are analytically formulated and solved using a symbolic calculation technique. To verify the validity of the experimental and the proposed analytical theories, the results obtained using FEM models composed of beam elements, rigid beam elements, and truss cable elements, are compared to the experimental results and the analytical solutions. As a result, it is determined that externally installed un-bonded deviators inhibit flexural deformation of the deformed beam to such an extent that their elastic stiffness, and failure strength are significantly improved compared to those of the PS system without deviators.

Lane Departure Warning System Using Top-view Space (Top-view 공간을 활용한 차선 이탈 경보 시스템)

  • Park, Han-dong;Oh, Jeong-su
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.05a
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    • pp.815-818
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    • 2016
  • Forward collision warning systems(FCWS) and lane departure warning systems(LDWS) need regions of interest for detecting lanes and objects as road regions. In general, the lane departure warning system using a vehicle front camera is tracking a lane curve using RANSAC or the like in the form of a straight line obtained image are compared with the center of the vehicle. This algorithm has weaknesses that requires a wide range of the lane being vulnerable to the curve. This paper presents an algorithm that checks whether the current lane departure by car from the Top-view space. The algorithm also can check whether the vehicle in the lane departure of the narrow range, and shows the result that is almost not affected by noise.

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Prediction of River Discharge by Using Mean Velocity Equation (평균유속공식을 활용한 하천 유량예측)

  • Choo, Tai-Ho;Chae, Soo-Kwon;Yoon, Hyeon-Cheol;Song, Jung-Ju
    • Proceedings of the Korea Water Resources Association Conference
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    • 2012.05a
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    • pp.135-139
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    • 2012
  • 하천에서의 정확한 유량 산정은 하천의 설계 및 운영 유지에 매우 중요한 요소이다. 현재 하천의 유량 생산은 수위-유량관계곡선을 통하여 이루어지고 있다. 수위-유량관계곡선법은 측정된 수위와 유량자료의 관계를 바탕으로 홍수기 때의 유량을 회귀 추정법으로 예측하여 사용하는 방법이다. 비교적 간편하게, 특히 측정이 어려운 홍수기 때의 유량을 예측하여 사용할 수 있다는 장점을 가지고 있지만 수위와 유량만의 관계를 사용하므로 하천의 수리학적 특성을 반영하기 곤란하기 때문에 기본적으로 개선되어야 할 사항이 있다. 따라서, 본 연구에서는 하천유량을 예측하는 새로운 방법론의 하나로 KSCE에 기 게재된 Choo 등(2011)의 방법에 따라, 개수로에서 널리 사용되어 오고 있는 Manning식과 Chezy식을 활용하여 하천의 전체적인 특성을 잘 반영하는 특성조도계수 n과 특성Chezy계수 C를 사용하여 하천의 유량을 예측하였다. 실험실 직선수로에서 측정된 정류 자료와 객관성 있는 해외 하천 유량측정 자료를 사용하여 증명하였고 결정계수 0.8 정도 수준의 높은 정확성을 보여주는 성과를 나타내었다. 따라서 본 연구결과를 통해 하천의 수리학적 특성을 반영하면서도 간단하게 유량을 예측할 수 있는 방법으로 실무에서 간편하게 활용될 수 있을 것으로 기대한다.

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Studies on the Response of Barley Varieties to Nitrogen Application and Seeding Methods (보리의 안전증수를 위한 질소비료의 효율적 이용에 관한 연구)

  • Hong-Suk Lee;Eun-Woong Lee;Ho-Young Lee
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.20
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    • pp.152-162
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    • 1975
  • Five barley varieties were compared under six 1evels of nitrogen fertilization and two methods of cultural management, conventional and drill seeding. The increase in grain yield and nitrogen content of the leaves showed a significant linear regression from added increaments of nitrogen in Haganemugi and Olbori, particulary under drill seeding. The other varieties resulted in various degrees of lodging and no significant increases in yield. The spike number per square meter was the major component of yield, but when the spike number per square meter was sufficient, 1000 grain weight was equally as important as a component of yield.

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Transport of Some Solutes in Blood Plasma Through Poly(2-Hydroxyethyl Methacrylate) Hydrogel Membrane (혈장내 염의 Poly(2-Hydroxyethyl Methacrylate) 격막 투과현상)

  • Jee Jong Gi;Jhon Mu Shik;Ree Tai Kyue
    • Journal of the Korean Chemical Society
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    • v.22 no.5
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    • pp.304-310
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    • 1978
  • The relative permeabilities, distribution coefficients and diffusion coefficient of some salts which are important components in blood plasma through a poly(HEMA) membrane were measured. The crosslinker which was used for preparing the membrane was tetraethylene glycol dimethacrylate(TEGDMA), the weight percentage of the latter was about 2.8. We found that the diffusion coefficients ($D_m$) of the solutes decrease exponentially with increasing molecular weight, and also that $D_m$'s decrease linearly (except urea) with cylindrical radius (a). These facts were explained by a sieve pore flow model. The relative permeability and diffusion coefficient of urea at various temperature were larger than those of other solutes such as glycine, ${\beta}$-alanine, D-glucose, saccharose and maleic acid. The result indicates that the poly(HEMA) membrane might be suitable for hemodialysis application.

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A Study on customer satisfaction with self technological - based product (정보화시대의 무인자동화 제품디자인이 고객만족에 미치는 영향에 관한 연구 - 중요사건기법(critical incident technique)을 중심으로 -)

  • 박종찬
    • Archives of design research
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    • v.17 no.3
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    • pp.283-292
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    • 2004
  • Today's fast-paced world is becoming increasingly characterized by technology-facilitated transactions. Growing numbers of customers interact with technology to create service outcomes instead of interacting with a service firm employee. Self-service technologies provide technological interfaces that enable customers to produce a service independent of direct service employee involvement. To investigate on the customer satisfaction with self-technological based product design in Subway. I used the critical incident technique developed by Flanagan(1954) with quantitative measures of attributions. In this research, it results that customers are considered more important the value of technological-function and easy to use than the aspect of automated machine. It is likely that the technological aspect of many self-service options has a unique influence on customer perceptions of self-service encounters. Also, Research has shown that customer's needs are defined as situations in which external environmental factors add a sense of urgency to the transaction and saved time. On the other hand, customers realize that their favorable image of self-technological based product follows as ; first, customers prefer to the simple & modern image on the aspect of product design, secondly, customers prefer to the hitech-functional image to do its job fast in a short time by automated technology on the aspect of functional service, thirdly, customers prefer to the comfortable and sanitary image to be suitable for the underground circumstance.

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Evaluation for Rock Cleavage Using Distribution of Microcrack Spacings (III) (미세균열의 간격 분포를 이용한 결의 평가 (III))

  • Park, Deok-Won
    • The Journal of the Petrological Society of Korea
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    • v.25 no.4
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    • pp.311-324
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    • 2016
  • The characteristics of the rock cleavage in Jurassic granite from Geochang were analysed. The evaluation for three quarrying planes and three rock cleavages was performed using the parameters such as (1) reduction ratio between the value of spacing and the value of length, (2) microcrack spacing frequency(N), (3) total spacing($1mm{\geq}$), (4) exponential constant(a), (5) magnitude of exponent(${\lambda}$), (6) mean spacing($S_{mean}$), (7) difference value($S_{mean}-S_{median}$) between mean spacing and median spacing($S_{median}$) and (8) density of spacing. Especially the close dependence between the above spacing parameters and the parameters from the spacing-cumulative frequency diagrams was derived. The discrimination factors representing three quarrying planes and three rock cleavages were acquired through these mutual contrast. The analysis results of the research are summarized as follows. First, the reduction ratios of frequency(N), mean value, median value, the above difference value($S_{mean}-S_{median}$) and density for three rock cleavages are in orders of G(grain, (G1 + G2)/2) < H(hardway, (H1 + H2)/2) < R(rift, (R1 + R2)/2), H < G $\ll$ R, H < G $\ll$ R, H < G < R and H < G $\ll$ R. The values of the above five parameters for three planes show the various orders of R'(rift plane) $\ll$ H'(hardway plane) < G'(grain plane), R' $\ll$ G' < H', R' < H' < G', R' < G' < H' and R' $\ll$ H' < G', respectively. Second, the values of (I) parameters(2, 3, 4 and 5) and (II) parameters(6, 7 and 8) are in orders of (I) H < G < R and (II) R < G < H. On the contrary, the values of the above two groups(I~II) of parameters for three planes show reverse orders. Third, to review the overall characteristics of the arrangement among the six diagrams, these diagrams show an order of R2 < R1 < G2 < G1 < H2 < H1 from the related chart. In other words, above six diagrams can be summarized in order of rift(R1 + R2) < grain(G1 + G2) < hardway(H1 + H2). These results indicate a relative magnitude of rock cleavage related to microcrack spacing. Especially, two parameters for each diagram, the above difference value($S_{mean}-S_{median}$) and mean spacing, could provide advanced information for prediction the order of arrangement among the diagrams. Finally, the general chart for three planes and three rock cleavages were made. From the related chart, three exponential straight lines for three rock cleavages show an order of R(R1 + R2) < G(G1 + G2) < H(H1 + H2). On the contrary, three lines for three planes show an order of H'(R2 + G2) < G'(R1 + H2) < R'(G1 + H1). Consequently, correlation of the mutually reverse order between three planes and three rock cleavages can be drawn from the related chart.

The Investigation and Development of Astigmatism Correction Treatments by Finite Element Method and Animal Experiments (유한요소법과 동물실험을 통한 난시교정술의 고찰 및 개발)

  • Sin, Jeong-Uk;Han, Tae-Won;Kim, Su-Hyang;Kim, Jae-Ho;Lee, Seong-Jae;Park, Hyo-Sun
    • Journal of Biomedical Engineering Research
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    • v.20 no.1
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    • pp.45-51
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    • 1999
  • The purpose of this study is to investigate the effects of various factors in keratotomy for astigmatism correction on surgical outcomes by finite element method as well as animal experiments. Three kinds of surgical techniques were mechanically investigated : arcuate, straight, and inverse arcuate keratotomy. Among the three techniques the arcuate keratotomy is the most popular one while the other two techniques are being investigated in this area. The arcuate keratotomy was found to be more controllable and effective in reducing the refractive power than the others. In arcuate keratotomy it was found most effective when the incision was located in the middle position between the apex and the edge of the cornea from the results of experiment as well as finite element study. Regarding to the range of the corneal incision in arcuate keratotomy, the incision angle of 90$^{\circ}$ was found th be most effective in reducing refractive power than other angles even it was incised up to 150$^{\circ}$. Therefore, it was concluded that 90$^{\circ}$ of incision angle results in the largest decrease in refractive power in arcuate keratotomy. However, other important findings were that the effect of the surgery decreased with time so the visco-effect of the cornea and auto-healing process. Therefore, these factors should be considered in future studies.

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Algorithm for Identifying Highway Horizontal Alignment using GPS/INS Sensor Data (GPS/INS 센서 자료를 이용한 도로 평면선형인식 알고리즘 개발)

  • Jeong, Eun-Bi;Joo, Shin-Hye;Oh, Cheol;Yun, Duk-Geun;Park, Jae-Hong
    • International Journal of Highway Engineering
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    • v.13 no.2
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    • pp.175-185
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    • 2011
  • Geometric information is a key element for evaluating traffic safety and road maintenance. This study developed an algorithm to identify horizontal alignment using global positioning system(GPS) and inertial navigation system(INS) data. Roll and heading information extracted from GPS/INS were utilized to classify horizontal alignment into tangent, circular curve, and transition curve. The proposed algorithm consists of two components including smoothing for eliminating outlier and a heuristic classification algorithm. A genetic algorithm(GA) was adopted to calibrate parameters associated with the algorithm. Both freeway and rural highway data were used to evaluate the performance of the proposed algorithm. Promising results, which 90.48% and 88.24% of classification accuracy were obtainable for freeway and rural highway respectively, demonstrated the technical feasibility of the algorithm for the implementation.