• 제목/요약/키워드: Weight and Center of Gravity

검색결과 116건 처리시간 0.027초

Evaluation of dynamic behaviors of gravity-based structures under seismic load considering fluid-structure-ground interactions

  • Hyo-Jin Kim;Sunghun Jung;Seongpil Cho
    • Structural Engineering and Mechanics
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    • 제88권3호
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    • pp.251-262
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    • 2023
  • This paper presents a method for assessing the dynamic responses of gravity-based structures (GBS) under various seismic loads, with a focus on fluid-structure-ground interactions. Models of GBSs and their surrounding environments were developed, incorporating interaction effects among the structure, seawater, and seabed. Dynamic responses of the GBS subjected to three seismic loads-Chi-Chi, Northridge01, and Northridge02-were calculated, with consideration of both horizontal and vertical accelerations, as well as displacements. Parametric studies indicated that the primary factors affecting the dynamic responses of GBS were seismic loads characterized by significant input forces and accelerations. The frictional force on the ground had minimal impact on the horizontal and vertical displacements of the GBS. Weight emerged as a critical factor in anchoring the GBS to the ground and minimizing vertical accelerations and displacements.

플랜트 구조물의 모듈화 공법 (Modularization of plant structures)

  • 서한설;장상수
    • 플랜트 저널
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    • 제13권3호
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    • pp.30-35
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    • 2017
  • Module은 세부적으로 PAS(Pre-Assembled Steel structure), PAR(Pre-Assembled pipe Rack), PAU(Pre-Assembled Unit), VAU(Vendor Assembled Unit) 그리고 VPU(Vendor Package Unit)로 분류될 수 있다. 이러한 Module의 설계 및 제작 시에는 Stick built type 구조물과는 달리 육상 또는 해상 운송 조건이 고려되어야 하며, 운송 조건에 따른 Module division design이 수반되어야 한다. 육상 운송 및 설치를 위해서는 무게중심(Center of gravity) 관리가 중요하며, 해상 운송을 위해서는 구조물이 Sea acceleration force에 대해 안전성을 확보할 수 있도록 설계되어야 한다. 운송 조건 및 설치 방법은 구조물의 규모와 무게를 제한하게 되며, 이는 Module 대상 구조물 선정 시, 그리고 선정된 Module의 분할 계획 시 요구조건으로 작용하게 된다.

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Aerodynamic Design of the Solar-Powered High Altitude Long Endurance (HALE) Unmanned Aerial Vehicle (UAV)

  • Hwang, Seung-Jae;Kim, Sang-Gon;Kim, Cheol-Won;Lee, Yung-Gyo
    • International Journal of Aeronautical and Space Sciences
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    • 제17권1호
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    • pp.132-138
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    • 2016
  • Korea Aerospace Research Institute (KARI) is developing an electric-driven HALE UAV in order to secure system and operational technologies since 2010. Based on the flight tests and design experiences of the previously developed electric-driven UAVs, KARI has designed EAV-3, a solar-powered HALE UAV. EAV-3 weighs 53kg, the structure weight is 22kg, and features a flexible wing of 19.5m in span with the aspect ratio of 17.4. Designing the main wing and empennage of the EAV-3 the amount of the bending due to the flexible wing, 404mm at 1-G flight condition based on T-800 composite material, and side wind effects due to low cruise speed, $V_{cr}=6m/sec$, are carefully considered. Also, unlike the general aircraft there is no center of gravity shift during the flight because of the EAV-3 is the solar-electric driven UAV. Thus, static margin cuts down to 28.4% and center of gravity moves back to 31% of the Mean Aerodynamic Chord (MAC) comparing with the previously designed the EAV-2 and EAV-2H/2H+ to upgrade the flight performance of the EAV-3.

가방 휴대방법과 무게에 따른 어깨높이, 중력 중심선과 발바닥 압력 변화 연구 (The investigation of shoulder height, center of gravity and plantar pressure by backpack weight and location)

  • 손선주;한민규;이혜진;서영미;박하나;이상영;박철우;권구현;김형수
    • 대한물리치료과학회지
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    • 제18권3호
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    • pp.71-78
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    • 2011
  • Purpose : The purpose of this study found change that caused by various form and weight of bag. So we investigated how these things change the shoulder altitude and space between external acoustic pore and lateral malleolus and also plantar pressure. Method : We measured two different way for this study. One was backpack with 5, 10kg and another one was shoulder pack with same weight. Each trial was 10 seconds in duration with static stance posture. With these experiments, we checked space between plantar pressure, shoulder altitude, external acoustic pore and lateral malleolus with EMED system and GPS. We analyzed these results with PASW(SPSS) statistics 18.0. Result : In conclusion, there were no significantly differences in shoulder altitude by weight of pack, but average of plantar pressure and space between external acoustic pore and lateral malleolus was increased.

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Foundation Types of Fixed Offshore Wind Turbine

  • Yun Jae Kim;Jin-wook Choe;Jinseok Lim;Sung Woong Choi
    • 한국해양공학회지
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    • 제38권2호
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    • pp.74-85
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    • 2024
  • Offshore wind turbines are supported by various foundations, each with its considerations in design and construction. Gravity, monopile, and suction bucket foundations encounter geotechnical issues, while jacket and tripod foundations face fatigue problems. Considering this, a gravity foundation based on a steel skirt was developed, and a monopile foundation was analyzed for Pile-Soil Interaction using the p-y curve and 3D finite element method (3D FEM). In addition, for suction bucket foundations, the effects of lateral and vertical loads were analyzed using 3D FEM and centrifuge tests. Fatigue analysis for jacket and tripod foundations was conducted using a hotspot stress approach. Some hybrid foundations and shape optimization techniques that change the shape to complement the problems of each foundation described above were assessed. Hybrid foundations could increase lateral resistance compared to existing foundations because of the combined appendages, and optimization techniques could reduce costs by maximizing the efficiency of the structure or by reducing costs and weight. This paper presents the characteristics and research directions of the foundation through various studies on the foundation. In addition, the optimal design method is presented by explaining the problems of the foundation and suggesting ways to supplement them.

경어뢰의 정특성 허용오차 산정 (An Evaluation of the Tolerance of the Static Characteristics for Light Weight Torpedoes)

  • 나영인
    • 한국군사과학기술학회지
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    • 제5권2호
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    • pp.149-158
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    • 2002
  • Static Characteristics of the system, such as weight, center of gravity etc., are inspected and regulated through the whole design process of a light weight torpedo system, and the nominal condition of the characteristics is prescribed for standardization of manufacturing and fabrication. It is possible that a real system or assembled system has different static characteristics from that of the nominal condition. It is required to evaluate the tolerance of the static characteristics within which the performance of the system should not be contaminated by the static characteristics. In this paper, an evaluation method of the tolerance is described for light weight torpedo systems. The method is to check on the performance and related critical parameters of light weight torpedoes. The checking items are composed of general conditions of underwater mobile systems such as stability and dynamic sensitivity and specified performance requirements for light weight torpedoes.

최적 적재를 위한 컨테이너 시큐어링 시스템 개발에 관한 연구 (A Study on Container Securing System for Optimum Arrangement)

  • 신상훈
    • 한국항해항만학회지
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    • 제27권4호
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    • pp.397-402
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    • 2003
  • 컨테이너 시큐어링 시스템은 컨테이너 운반선 상갑판에 적재되는 컨테이너의 배치 설계를 위한 시스템이다. 컨테이너의 배치는 각 선급의 가이드라인에 기초하여 설계되어지며, 주어진 배치에 따른 반력들과 변력의 한계값을 제공하고 있다. 컨테이너 설계를 위해서는 컨테이너 구속 교량(lashing bridge)과 수직 구속 장치(vertical lashing) 등을 고려해야 하며, 최대 수직 중량 중심(vertical center of gravity, VCG)과 최대 화물 중량(stack weight)을 갖는 배치안을 제시할 수 있어야 한다. 본 연구에서는 이를 위한 평형방정식을 정립하였으며, 배치안 계산을 위해 등식 제한조건(equality constraint)을 처리할 수 있는 최적화 알고리즘을 적용하여 새로운 컨테이너 시큐어링 시스템을 개발하였다. 개발된 시스템은 컨테이너 배치 설계 시간을 크게 줄여주며, 설계자가 원하는 배치 설계안을 제시해 준다.

마비측에 적용한 외측 쐐기 깔창이 뇌졸증 환자의 체중부하율과 균형, 보행에 미치는 영향 (The Effects of Lateral Wedged Insole to the Shoe of the Affected Side on Weight Bearing, Balance and Gait with Stroke)

  • 김혜림;신원섭
    • PNF and Movement
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    • 제11권2호
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    • pp.21-29
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    • 2013
  • Purpose : The study was to evaluate the weight distribution, balance and gait function of stroke patients wearing lateral wedged insole to the shoe of the affected side. Methods : 27 patients with stroke (15 men, 12 women) participated in this study. Participants performed weight distribution, dynamic balance and gait ability with or without wedged insole on affected side in a random order. The balancia was used to evaluate the weight distribution. Deviation from the center line was analyzed by Dartfish during sit to stand to evaluate dynamic balance. The functional walk ability evaluated by 10 m walking velocity. Results : The asymmetry index of weight bearing improved significantly with wedged insole of affected side(p<.05). During sit to stand, center of gravity significantly moved from non-affected side to more mid line of body(p<.05). Improvement were shown in walking speed after wearing the wedged insole(p<.05). Conclusion : Wedged insole applied on affected side have a beneficial effect on weight distribution, dynamic balance and walking speed with stroke.

Studies on the Physiological Characteristics of (Cervus e. canadensis) Velvet Antler in Elk

  • Jeon, Byong-Tae;Thomas, David G.;Cheong, Sun-Hee;Kim, Myeong-Hwa;Kim, Sung-Jin;Sung, Si-Heung;Park, Pyo-Jam;Park, Jae-Hyun;Moon, Sang-Ho
    • Journal of Animal Science and Technology
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    • 제52권3호
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    • pp.237-244
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    • 2010
  • In order to investigate the physiological properties of velvet antler of elk (Cervus e. canadensis) raised in Korea, antlers (n=378) were collected from deer in 8 provinces including Gyeonggi-do (n=53), Gangwon-do (n=49), Chungcheongbuk-do (n=62), Chungcheongnam-do (n=68), Jeollabuk-do (n=52), Jeollanam-do (n=15), Gyeongsangbuk-do (n=30) and Gyeongsangnam-do (n=49). The exterior characteristics (weight, length, girth and crown) of all antlers were measured, and 18 antler samples were randomly selected for measurement of interior characteristics such as specific gravity, capacity and diameter of cross section. The mean antler weight, length of the main beam and mean length of upper section were $4.87{\pm}1.79\;kg$, $83.7{\pm}13.2\;cm$ and $40.6{\pm}11.4\;cm$, respectively. Mean girth of the top, middle and base of the main beam were $27.1{\pm}5.9\;cm$, $22.1{\pm}3.6\;cm$ and $22.9{\pm}3.6\;cm$ respectively, indicating a slight narrowing in the middle of the antler. In each of the tines, the girth at the base was markedly thicker compared to the top. The depth of the crown at the top of the antler, and the average number of crowns and tines were $14.1{\pm}7.0\;cm$, $2.1{\pm}0.6$ and $3.0{\pm}0.5$, respectively. Although there was no significant difference in mean specific gravity between top and base, mean specific gravity of main beam tended to increase from top to base of the antler with decreasing capacity. Additionally, the inner diameter of the base of the antler was significantly reduced compared to that of the top, indicating a greater integumental thickening due to mineralization. Information on the morphological and physiological properties of elk antlers is scarce. Therefore, these results may be useful in providing basic information for the physiological properties of antler, and encourage further studies on antler morphology in other deer species showing species specific differences.

항공기 탑재 관리사들의 개인 특성에 따른 Weight and Balance C.G. 결과 (A Study on Result Differences of Flight's Weight and Balance by Load Master)

  • 이규진;이윤철
    • 한국항공운항학회지
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    • 제23권3호
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    • pp.81-87
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    • 2015
  • Load master is authorized to be controlled all of loading stuffs for safety of flight such as passenger, baggage, cargo and e.t.c. There are many things are missed even though the weight and balance is the most important process. This study analyzes how the differences of C.G. by among ten load masters of each careers. This study is tested how load-master takes load-control by the respective result based on differences of each practical experiences, gender and a number of certification. In result, all of load masters set C.G. on the stability region. But the practical experience of load master is relative to set better C.G. for economical effectiveness of weight and balance control work.