• Title/Summary/Keyword: slender

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Experimental Study on Elastic Response of Circular Cross-section Slender Body to Forced Oscillation, Waves, and Current (복합 외력환경 중 원형 단면 세장체의 탄성응답에 관한 실험적 연구)

  • Park, Ji-won;Lee, Seung-Jae;Jo, Hyo-Jae;Hwang, Jae-Hyuk;Han, Sung-Hoon
    • Journal of Ocean Engineering and Technology
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    • v.30 no.2
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    • pp.91-99
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    • 2016
  • The global demand for oil and natural gas has increased, and resource development is moving to the deep sea. Floating and flexible offshore structures such as semi-submersible, spar, and FPSO structures have been widely used. The major equipment of floating structures is always exposed to waves, currents, and other marine environmental factors, which cause structural damage. Moreover, flexible risers are susceptible to an exciting force due to the motion of the floating body. The inline and transverse responses from the three-dimensional behavior of a floating structure occur because of various forces. Typical risers are made of steel pipe and applied in the oil and gas development field, but flexible materials such as polyethylene are suitable for OTEC risers. Consequently, the optimal design of a flexible offshore plant requires a dynamic behavior analysis of slender bodies made of the different materials commonly used for offshore flexible risers. In this study, a three-dimensional motion measurement device was used to analyze the displacements of riser models induced by external force factors, and forced oscillation of a riser was linked to forced oscillation under a steady flow and regular wave condition.

Cyclic Behavior of Precast Slender Coupling Beams with Bundled Diagonally Reinforcement and High-Performance Fiber Reinforced Cementitious Composite(HPFRCC) (묶음 대각철근과 고성능 섬유보강 시멘트 복합체를 적용한 세장한 프리캐스트 연결보의 이력거동 평가)

  • Han, Sang Whan;Yu, Kyung Hwan;Kang, Dong Hun;Lee, Ki Hak;Shin, Myung Su
    • Journal of the Earthquake Engineering Society of Korea
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    • v.19 no.2
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    • pp.55-62
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    • 2015
  • Shear wall systems behave as individual wall because of openings like window and elevator cage. When coupling beams are installed in shear walls, they will have high strength and stiffness so that be less damaged by lateral loads like earthquake. However, coupling beam is difficult construction method. And arranging reinforcement of slender coupling beams are especially hard. It is because the details of coupling beam provided by ACI 318 are complex. In this paper, experiments were conducted using coupling beams with 3.5 aspect ratio to improve the details of slender coupling beams provided by ACI 318. Two specimens were proposed for this study. One specimen applied with bundled diagonally reinforcement only. Another specimen applied both bundled diagonally reinforcement and High-Performance Fiber Reinforced Cementitious Composite (HPFRCC) so that coupling beams have half of transverse reinforcement. All specimen were compared with a coupling beam designed according to ACI 318 and were evaluated with hysteretic behaviors. Test results showed that the performance of two specimen suggested in this study were similar to that of coupling beam designed according to current criteria. And it was considered that simplification of the details of reinforcement would be available if transverse reinforcement was reduced by using bundled diagonally reinforcement and HPFRCC.

The Effects of Clothing Styles and Colors on a Body Image Perception (의복스타일과 색이 신체이미지 지각에 미치는 영향)

  • Kim, Hyo-Sook;Choi, Chang-Seok;Lee, Eun-Sil
    • Journal of the Korean Home Economics Association
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    • v.41 no.9
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    • pp.135-148
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    • 2003
  • The purpose of this study was to examine the effect of clothing colors, clothing styles on women's body image perception. The experimental design was 2${\times}$2${\times}$9(perceiver's gender ${\times}$clothing styles${\times}$clothing colors) factorial design with between-subjects design. Subjects were 320 college students in the metropolitan area of Seoul. Perceiver's gender, clothing styles, and clothing colors gave a significant influence on the 3 variables of shoulder, the upper half of the body, and bust. Shoulder and the upper half of the body had an interaction effect by clothing styles and clothing color. Perceiver's gender gave a significant influence on hip size, length of leg, height, clothing styles did a significant influence on hip size, length of leg, height, and slender figure. Clothing colors gave a significant influence on length of leg, height, and slender figure. Length of leg and slender figure had an interaction effect by perceiver's gender and clothing styles. Hip size had an interaction effect by perceiver's gender and clothing color. Hip size had an interaction effect by clothing styles and clothing color. The results of this study support that coloration of clothing and clothing style affects perception of stimulus persons wearing apparel.

Evaluation of Two Robot Vision Control Algorithms Developed Based on N-R and EKF Methods for Slender Bar Placement (얇은막대 배치작업에 대한 N-R 과 EKF 방법을 이용하여 개발한 로봇 비젼 제어알고리즘의 평가)

  • Son, Jae Kyung;Jang, Wan Shik;Hong, Sung Mun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.4
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    • pp.447-459
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    • 2013
  • Many problems need to be solved before vision systems can actually be applied in industry, such as the precision of the kinematics model of the robot control algorithm based on visual information, active compensation of the camera's focal length and orientation during the movement of the robot, and understanding the mapping of the physical 3-D space into 2-D camera coordinates. An algorithm is proposed to enable robot to move actively even if the relative positions between the camera and the robot is unknown. To solve the correction problem, this study proposes vision system model with six camera parameters. To develop the robot vision control algorithm, the N-R and EKF methods are applied to the vision system model. Finally, the position accuracy and processing time of the two algorithms developed based based on the EKF and the N-R methods are compared experimentally by making the robot perform slender bar placement task.

Concentrated Axial Loading Test for Slender Square Hollow Section Retrofitted by Carbon Fiber Reinforced Polymer Sheets(CFRP Sheets) (탄소섬유쉬트(CFRP Sheets)로 보강된 세장한 각형강관기둥의 중심축하중실험)

  • Park, Jai Woo;Choi, Sun Kyu;Choi, Sung Mo;Song, Dong Yub;Yoo, Jung Han
    • Journal of Korean Society of Steel Construction
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    • v.24 no.6
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    • pp.735-742
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    • 2012
  • This paper presents the experimental results of axially loaded stub columns of slender steel hollow square section(SHS) strengthened with carbon fiber reinforced polymers(CFRP) sheets. 6 specimens were fabricated and the main parameters were: width-thickness ratio(b/t) and CFRP retrofitting. From the tests, it was observed that two sides would typically buckle outward and the other two sides would buckle inward. A maximum increase of 33% was achieved in axial-load capacity. Also, stiffness and ductility index(DI) were compared between unretrofitted specimens and retrofitted specimens. In the last section, a prediction formula of the ultimate strength developed using the experimental results is presented.

Modeling shear capacity of RC slender beams without stirrups using genetic algorithms

  • Nehdi, M.;Greenough, T.
    • Smart Structures and Systems
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    • v.3 no.1
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    • pp.51-68
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    • 2007
  • High-strength concrete (HSC) is becoming increasingly attractive for various construction projects since it offers a multitude of benefits over normal-strength concrete (NSC). Unfortunately, current design provisions for shear capacity of RC slender beams are generally based on data developed for NSC members having a compressive strength of up to 50 MPa, with limited recommendations on the use of HSC. The failure of HSC beams is noticeably different than that of NSC beams since the transition zone between the cement paste and aggregates is much denser in HSC. Thus, unlike NSC beams in which micro-cracks propagate around aggregates, providing significant aggregate interlock, micro-cracks in HSC are trans-granular, resulting in relatively smoother fracture surfaces, thereby inhibiting aggregate interlock as a shear transfer mechanism and reducing the influence of compressive strength on the ultimate shear strength of HSC beams. In this study, a new approach based on genetic algorithms (GAs) was used to predict the shear capacity of both NSC and HSC slender beams without shear reinforcement. Shear capacity predictions of the GA model were compared to calculations of four other commonly used methods: the ACI method, CSA method, Eurocode-2, and Zsutty's equation. A parametric study was conducted to evaluate the ability of the GA model to capture the effect of basic shear design parameters on the behaviour of reinforced concrete (RC) beams under shear loading. The parameters investigated include compressivestrength, amount of longitudinal reinforcement, and beam's depth. It was found that the GA model provided more accurate evaluation of shear capacity compared to that of the other common methods and better captured the influence of the significant shear design parameters. Therefore, the GA model offers an attractive user-friendly alternative to conventional shear design methods.

A Study on the Adjustment of Eaves Curve and Roof Length of Three-Bay-Kan Buddhist Temples with the Hipped and Gable Roof (정면 3칸 팔작지붕 불전의 처마 곡선과 지붕 길이 조절에 관한 연구)

  • Wi, So-Yeon;Sung, Dae-Chul;Shin, Woong-Ju
    • Journal of architectural history
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    • v.26 no.3
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    • pp.39-49
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    • 2017
  • It is difficult to build a hipped and gable roof in slender rectangular type due to restraint in variation of lateral length caused by gongpo arranged on the side, purlin space and the form of gable part and aesthetical effect of chunyeo maru. Against this backdrop and with the assumption that this phenomenon is more apparent in roofs of three-bay-kan Buddhist temples with the hipped and gable roof among national treasure Buddhist temples, this study has aimed to prove that a roof can be built in a less slender rectangular type than that of flat form and to present the building methodology and found the following findings. First, The ratio of lateral to longitudinal length of the roof has been adjusted by protruding the chunyeo and the method of adjusting the ratio of lateral to longitudinal length of the roof is considered to be determined depending on the availability of woods to be used in chunyeo. Second, in order to symmetrically arrange the edge of the roof, which is critical from the perspective of construction morphology, the chunyeo angle has been intentionally adjusted to reduce the gap of length between the front roof and the lateral roof. To sum up, the characteristic of the hipped and gable roof, which is difficult to be built in slender rectangular type, is more clearly shown in the roof and it is identified that the length of the front roof and the lateral roof has been intentionally adjusted to achieve the symmetrical arrangement of roofline of the roof edge.

Dynamic Response Analysis of Slender Marine Structures under Vessel Motion and Regular Waves (파랑 및 부유체 운동을 고려한 세장해양구조물의 동적 거동 해석)

  • Chung Son Ryu;Michael Isaacson
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.10 no.2
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    • pp.64-72
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    • 1998
  • Dynamic response analysis is carried out for slender marine structures such as tensioned risers and tethers of tension leg platform, which are subjected to floating vessel motions as well as environmental forces arising from ocean waves. A mumerical analysis procedure is developed by using finite element model of the structural member. Dynamic analses are performed in the time domain for regular waves. Parameter studies are carried out to highlight the effects of surface vessel motions on the lateral dynamics of the structures. Example results of displacements, bending stresses are compared for various in water depth, environmental condition and vessel motion. Some instability conditions of the structures due to time-varying tension by vessel heave motion are discussed through the example analyses. As the results, the interaction between vessel surge and heave motions amplifies the total structural response of a riser. In the case of a tether, the effect of vessel heave motion during heavy storm is seemed to be quite significant to lateral response of the structure.

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