• Title/Summary/Keyword: 충격좌굴

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A Study on the Lateral Pressure Effect under Axial Compressive Load of Ship Platings (종방향 압축력을 받는 선체판부재의 횡압력 영향에 관한 연구)

  • Park, Joo-Shin;Ko, Jae-Yong;Lee, Jun-Kyo
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.29 no.1
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    • pp.61-67
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    • 2005
  • The ship plating is generally subjected to combined in-plane load and lateral pressure loads. In-plane loads include axial load and edge shear, which are mainly induced by overall hull ginder bending and torsion of the vessel. Lateral pressure is due to water pressure and cargo. These load components are not always applied simultaneously, but more than one can normally exist and interact. Hence, for more rational and safe design of ship structures, it is of crucial importance to better understand the interaction relationship of the buckling and ultimate strength for ship plating under combined loads. Actual ship plates are subjected to relatively small water pressure except for the impact load due to slamming and panting etc. The present paper describes an accurate and fast procedure for analyzing the elastic-plastic large deflection behavior up to the ultimate limit state of ship plates under combined loads. In this paper, the ultimate strength characteristics of plates under axial compressive loads and lateral pressure loads are inverstigated through ANSYS elastic-plastic large deflection finite element analysis with varying lateral pressure load level.

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Ultimate Strength Behavior Analysis on the Ship's Plate under Combined Load(Lateral Pressure Load and Axial Compressive Load) (조합하중을 받는 선체판부재의 최종강도거동 해석)

  • Park Jo-Shin;Ko Jae-Yong;Lee Jun-Kyo;Bae Dong-Kyun
    • Proceedings of KOSOMES biannual meeting
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    • 2005.05a
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    • pp.147-154
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    • 2005
  • The ship plating is generally subjected to combined in-plane load and lateral pressure loads. In-plane loads include axial load and edge shear, which are mainly induced by overall hull girder bending and torsion of the vessel. Lateral pressure is due to water pressure and cargo. These load components are not always applied simultaneously, but more than one can normally exist and interact Hence, for more rational and safe design of ship structures, it is of crucial importance to better understand the interaction relationship of the buckling and ultimate strength for ship plating under combined loads. Actual ship plates are subjected to relatively small water pressure except for the impact load due to slamming and panting etc. The present paper describes an accurate and fast procedure for analyzing the elastic-plastic large deflection behavior up to the ultimate limit state of ship plates under combined loads. In this paper, the ultimate strength characteristics of plates under axial compressive loads and lateral pressure loads are investigated through ANSYS elastic-plastic large deflection finite element analysis with varying lateral pressure load level.

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Structural Capacity of High Strength Steel Pipe Pile After Pile Driving (고강도 강관말뚝의 항타후 구조성능 분석)

  • La, SeungMin;Yoo, Hankyu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.6C
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    • pp.251-258
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    • 2011
  • Steel pipe piles have been used as various deep foundation materials for a long time. Recent increase in steel material cost has made engineers reluctant in using it even with its good quality and ease of construction. Therefore when constructing with steel pipe pile, the decision to reuse the excessive pile length that is cut off from the designed pile head elevation after pile driving can be cost saving. This has caused many constructors to reuse the pile leftovers with new piles, but the absence of quantitative structural capacity behaviors of steel pipe pile after pile driving or appropriate countermeasures and standards in reusing steel pipe pile has resulted in wrong applications, pile structural integrity problems, inappropriate limitation of reusable pile length, etc. The structural performance analysis between a new pile and a pile that has undergone working state and ultimate state stress level during pile driving was performed in this research by means of comparing the results between the dynamic pile load test, tensile load test, charpy energy test and fatigue test for high strength steel of $440N/mm^2$ yield strength. Test results show that under working load conditions the yield strength variation is less than 2% and for ultimate load conditions the variation is less than 5% for maximum total blow count of 3000. The results have been statistically analyzed to check the sensitivity of each factors involved. From the test results, reusability of steel pipe pile lies not in the main pipe yield strength deviation but in the reduction of absorb energy, strength changes and quality control at the welded section, shape deformation and local buckling during pile driving.

A Study on the Solar Panel Deployment of a Satellite (인공위성 태양전지판의 전개에 관한 연구)

  • Seo, Jong Hwi;Han, Sang Won;Park, Tae Won;Chae, Jang Su;Seo, Hyeon Seok
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.4
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    • pp.53-59
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    • 2003
  • Strain Energy Hinge(SEH) has been used in Korea Multi-purpose Satellite(KOMPSAT) series to deploy the solar panel due to the good record of reliability. However, when it reached a desired deployment position, a large buckling force is applied to the main body. This may cause structural damage and also affect control of the satellite. Therefore, reliable dynamic analysis for the deployment system is required at a design stage. Moreover, various mission of a satellite has made the size of solar panels got bigger, so elastic effect has to be considered seriously to get more precise analysis results. In this paper, a dynamic analysis method to predict the deployment is verified by KOMPSAT-2 deployment test.

Estimation of Modal Parameters for Plastic Film-Covered Greenhouse Arches (비닐하우스 아치구조의 모달계수 산정)

  • Cho, Soon-Ho
    • Journal of the Earthquake Engineering Society of Korea
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    • v.14 no.2
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    • pp.67-74
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    • 2010
  • To a series of vibration records obtained from experimental modal testing using a fixed hammer and roving accelerometers for greenhouse arch structures, modal parameters such as natural frequencies, damping ratios and mode shapes are extracted by applying the two most advanced system identification methods in the frequency-domain up to now, so-called PolyMAX and FDD. The former involves both input and output data, while the latter utilizes only the output data. The possibility of determining the static buckling load, detecting damages, etc., for very slender steel-pipe arches by means of a non-destructive testing method based on vibration measurements is primarily investigated. The extracted modal parameters generally correlated well with those obtained using finite element analysis, demonstrating promising results for further on-going research.

A Study on the Fuel Assembly Stress Analysis for Seismic and Blowdown Events (지진 및 냉각재상실사고시의 핵연료집합체 응력해석에 관한 연구)

  • Kim, Il-Kon
    • Nuclear Engineering and Technology
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    • v.25 no.4
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    • pp.552-560
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    • 1993
  • In this study, the detailed fuel assembly stress analysis model to evaluate the structural integrity for seismic and blowdown accidents is developed. For this purpose, as the first step, the program MAIN which identifies the worst bending mode shaped fuel assembly(FA) in core model is made. And the finite element model for stress calculation of FA components is developed. In the model the fuel rods (FRs) and the guide thimbles are modelled by 3-dimensional beam elements, and the spacer grid spring is modelled by a linear and relational spring. The constraints come from the results of the program MAIN. The stress analysis of the 16$\times$16 type FA under arbitary seismic load is performed using the developed program and modelling technique as an example. The developed stress model is helpful for the stress calculation of FA components for seismic and blowdown loads to evaluate the structural integrity of FA.

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Structural Stability of Temporary Facility System using High-Strength Steel Pipes Based on Abnormal Behavior Parameters (이상거동 변수 기반 고강도 강관 가시설 시스템의 구조 안정성)

  • Lee, Jin-Woo;Noh, Myung-Hyun;Lee, Sang-Youl
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.39 no.1
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    • pp.1-12
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    • 2019
  • This study defined abnormal behaviors such as bending deformations or buckling behaviors occurred in high strength steel pipe strut system, and carried out a full-scale bending test for different connection types. A parametric study was carried out to gain an insight about structural performances considering abnormal behavior effects in high strength steel pipe strut system. Five abnormal behaviors were considered as undesirable deflections of strut structures, which are basic load combination, excessive excavation situations, impact loading effects, additional overburden loads, load combinations, and strut lengths. Subsequent simulation results present various influences of parameters on structural performances of the strut system. Based on the results, we propose methods to prevent unusual behaviors of pipe-type strut structures made of high strength steels.

Investigation on Design and Impact Damage for a 500W Wind Turbine Composite Blade (500W급 풍력발전기 복합계 블레이드의 설계 및 충격손상 안전성 연구)

  • Kong, Chang-Duk;Choi, Su-Hyun;Park, Hyun-Bum;Kim, Sang-Hoon
    • Composites Research
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    • v.22 no.1
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    • pp.22-31
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    • 2009
  • Recently the wind energy has been alternatively used as a renewable energy resource instead of the mostly used fossil fuel due to its lack and environmental issues. This work is to propose a structural design and analysis procedure for development of the 500W class small wind turbine system which will be applicable to relatively low speed region like Korea and for the domestic use. The wind turbine blade was performed structural analysis including stress, deformation, buckling, vibration and fatigue. In addition, the blade should be safe from the impact damage due to FOD(Foreign Object Damage) including the bird strike. MSC.Dytran was used in order to analyze the bird strike penomena on the blade, and the applied method Arbitrary Lagrangian-Eulerian was evaluated by comparison with the previous study results. Finally, the structural test was carried out and its test results were compared with the estimated results for evaluation of the designed structure.

Fabrication and Characterization of Aluminum Honeycomb Panel (경량 알루미늄 허니콤 판재의 제작 및 특성 평가)

  • Kim, Kee Joo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.1
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    • pp.666-671
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    • 2018
  • A honeycomb panel is a plate made by attaching two surface plateson eitherside of a honeycomb core. The honeycomb plate hasexcellent specific strength and energy absorption and is suitable for use in regions where good impact resistance is required. Recently, with the increasing the need for a lightweight design to facilitate transportation, numerous studies have been conducted using aluminum honeycomb plates as body materials for vehicles such as automobiles and high-speed trains. In addition, honeycomb plates have excellent sound deadening properties, as well as excellent heat insulation and durability. Savings in weight using lightweight materials such as aluminum alloy for honeycomb panel's skin can lead to increase fuel economy and reduction in air pollution. In this study, in order to improve the design technology of the honeycomb plate material, the manufacturing technology of the aluminum honeycomb core and honeycomb plate material and various mechanical properties of the honeycomb plate were evaluated. From the results, it was found that the design of the manufacturing process of the aluminum honeycomb plate, as well as itsproduction and characteristics, were improved. The resulting excellent energy absorption capability of the honeycomb plate was due to the repetitive core buckling, indicating that the higher the compressive strength, the higher the strength per bonded area.