• Title/Summary/Keyword: 지지격자

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Failure Mode and Design Guideline for Reinforced Concrete Slab Strengthened Using Carbon FRP Grid (Carbon FRP Grid로 휨 보강한 철근콘크리트 슬래브의 파괴형태와 설계기준)

  • Park Sang-Yeol;Xian Cui
    • Journal of the Korea Concrete Institute
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    • v.16 no.5 s.83
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    • pp.667-675
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    • 2004

  • This paper presents the failure mode and strengthening design of reinforced concrete slab strengthened with Carbon Fiber Reinforced Polymer(CFRP) grid. Parameters involved in this experimental study are FRP grid reinforcement quantity, repair mortar thickness, the presence of anchor, and strengthening in compression. In this study, there are different failure types with increasing the CFRP grid strengthening reinforcement. On the low strengthening level, CFRP grid in repair mortar cover ruptures. On the moderate strengthening level, there is a debonding shear failure in the interface of carbon FRP grid because of the excessive shear deformation. On the high strengthening level, diagonal shear failure occurs. With the increasing of FRP grid reinforcement, the strengthening effect increased, but the ductility decreased. By limiting the strengthening level, it can be achieved to prevent shear failure which result in sudden loss in the resisting load capacity. CFRP rupture failure is desirable, because CFRP ruptured concrete slab keeps the same load capacity and ductility haying before strengthening even after failure. Finally, design guideline and procedure are given for strengthening of concrete slab with CFRP grid.

  • https://doi.org/10.4334/JKCI.2004.16.5.667 인용 PDF KSCI

Vibration Characteristics of a Dummy Fuel Rod Supported by Spacer Grids (지지격자로 지지된 모의 연료봉의 진동특성)

  • Choi, Myoung-Hwan;Kang, Heung-Seok;Yoon, Kyung-Ho;Kim, Hyung-Kyu;Song, Kee-Nam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.3
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    • pp.424-431
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    • 2003

  • The spacer grid is one of the main structural components in the fuel assembly, which supports the fuel rods and maintains coolable geometry from an external load. A vibration test and a finite element analysis using ABAQUS on a dummy fuel rod continuously supported by Optimized H type(OHT) and New Doublet (ND) spacer grids arc performed to obtain the vibration characteristics such as natural frequencies and mode shapes an(1 to verify a finite element model. The results from the test and the finite element analysis are compared by modal assurance criteria (MAC) values. It is resulted that MACs for the first, the third and the fifth mode shapes are relatively good as compared with those of the second an(1 fourth ones. The natural frequency differences between two methods as well as the mode comparison results for the rod with OHT spacer grid are better than those with ND spacer grid. It is judged that the FE model for the ND spacer grid spring should be modified to consider the long contact length which actually happen when the spring supports the rod.

  • https://doi.org/10.3795/KSME-A.2003.27.3.424 인용 PDF KSCI

Dynamic Crush Strength Analysis of a Spacer Grid Assembly for a LWR Nuclear Fuel Assembly(II) (경수로 핵연료 지지격자의 동적 좌굴강도 해석(II))

  • Song, Kee-Nam;Lee, S.B.
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.590-592
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    • 2008

  • A spacer grid is one of the most important structural components in a LWR nuclear fuel assembly. The primary considerations are to provide a Zircaloy spacer grid with crush strength sufficient to resist design basis loads, without significantly increasing pressure drop across the reactor core. In this study, the dynamic crush strength analysis and test are carried out for the specimens of a spacer grid assembly.

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Structural Design Considerations on the Spacer Grid Assembly of PWR Nuclear Fuel (경수로 핵연료 지지격자체 구조설계에 대한 소고)

  • Song, Kee-nam
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.7 no.3
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    • pp.54-60
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    • 2011

  • A spacer grid, which supports nuclear fuel rods laterally and vertically with a friction grip, is one of the most important structural components in a PWR fuel. The form of grid strap and supporting parts such as grid spring and dimple is known to be closely related with the mechanical/structural performance of spacer grid and nuclear fuel assembly. In this study, reviewing various research results for enhancing the performance of the spacer grid, some structural design considerations and research directions on the spacer grid assembly are suggested for further study.

  • https://doi.org/10.20466/KPVP.2011.7.3.054 인용 PDF