• Advances in concrete construction
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• 제9권6호
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• pp.569-576
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• 2020

Employment of the wave propagation approach with the combination of Pasternak foundation equation gives birth to the shell frequency equation. Mathematically, the integral form of the Lagrange energy functional is converted into a set of three partial differential equations. A cylindrical shell is placed on the elastic foundation of Pasternak. For isotropic materials, the physical properties are same everywhere, whereas the laminated and functionally graded materials, they vary from point to point. Here the shell material has been taken as functionally graded material. The influence of the elastic foundation, wave number, length and height-to-radius ratios is investigated with different boundary conditions. The frequencies of length-to-radius and height-to-radius ratio are counter part of each other. The frequency first increases and gain maximum value in the midway of the shell length and then lowers down for the variations of wave number. It is found that due to inducting the elastic foundation of Pasternak, the frequencies increases. It is also exhibited that the effect of frequencies is investigated by varying the surfaces with stainless steel and nickel as a constituent material. MATLAB software is utilized for the vibration of functionally graded cylindrical shell with elastic foundation of Pasternak and the results are verified with the open literature.

• 한국프랜차이즈경영연구
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• 제3권1호
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• pp.92-110
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• 2012

최근 경제적 불안과 실업율의 증가 등의 사회적인 문제로 인하여 창업시장의 수요가 증가 하는 가운데 청년창업 지원방안, 중기청 창업지원 계획 등의 정부의 창업 지원정책을 바탕으로 창업 시장은 지속적인 성장 추세를 보이고 있다. 이 같은 창업 시장의 확대에 힘입은 프랜차이즈 시장의 동반 상승이 예상되는 바, 프랜차이즈 시장에 대한 보다 현실적이고 구체적인 연구는 그 중요성이 점차 커질 것으로 사료된다. 본 연구에서는 가맹희망자의 브랜드 선택에 있어 기존에 선행연구를 개선하여 브랜드 선택에 영향을 미지는 선행 변수로 브랜드이미지, 본사의 지원, 창업비용, 정보탐색활동으로 보고 브랜드 선택에 영향을 미치는 요인을 규명하였으며, 그 결과는 다음과 같다. 첫째, 첫째, 창업업종 연령, 성별, 결혼여부에 따라 브랜드 이미지에 대한 생각 및 창업가능성에는 차이가 있다. 둘째, 예비창업자의 가맹계약의향에 있어 가장 중요한 요소는 경제적 특성이다. 브랜드 이미지 및 가맹지원, 정보탐색활동은 가맹희망자에게 있어 큰 영향을 미치는 속성으로 보기는 어려우며, 오히려 가맹점을 운영하는데 드는 비용(초기 창업비용 및 자기자본과의 일치성, 홍보비용, 운영자금, 시설/장비 재투자 등)이 중요한 속성인 것으로 나타났다. 특히 초기 창업비용과 자기자본과의 일치성은 가맹희망자에게 있어 가장 중요한 요인인 것으로 나타났다.

• 대한조선학회논문집
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• 제51권3호
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• pp.179-183
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• 2014

The fluid loading effect has been investigated for the shipboard equipment foundation mobility with finite element model. For the purpose, two kinds of finite element models for 60m class ship have been developed: global and local model. The former is for low frequency range and the latter for middle frequency range. These finite element models contain added mass explaining fluid loading effect. Added mass has been implemented with virtual mass matrix derived from Laplace equation governing fluid surrounding ship hull. The mobility assessment result for diesel generator foundation of the objective model shows that the fluid loading effect should be considered, especially in low frequency range, to more accurately assess shipboard equipment foundation mobility.

• Coupled systems mechanics
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• 제3권4호
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• pp.367-384
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• 2014

The study deals with the physical modeling of a typical single storeyed building frame resting on pile foundation and embedded in cohesive soil mass using the finite element based software SAP-IV. Two groups of piles comprising two and three piles, with series and parallel arrangement thereof, are considered. The slab provided at top and bottom of the frame along with the pile cap is idealized as four noded and two dimensional thin shell elements. The beams and columns of the frame, and piles are modeled using two noded one dimensional beam-column element. The soil is modeled using closely spaced discrete linear springs. A parametric study is carried out to investigate the effect of various parameters of the pile foundation, such as spacing in a group and number of piles in a group, on the response of superstructure. The response considered includes the displacement at the top of the frame and bending moment in columns. The soil-structure interaction effect is found to increase the displacement in the range of 38 -133% and to increase the absolute maximum positive and negative moments in the column in the range of 2-12% and 2-11%. The effect of the soil- structure interaction is observed to be significant for the type of foundation and soil considered in this study. The results obtained are compared further with those of Chore et al. (2010), wherein different idealizations were used for modeling the superstructure frame and sub-structure elements (foundation). While fair agreement is observed in the results in either study, the trend of the results obtained in both studies is also same.

• KEPCO Journal on Electric Power and Energy
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• 제8권1호
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• pp.31-36
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• 2022

This paper presents the measuring process of dynamic properties of offshore wind power foundation and provides consideration of each step. This Guideline enables to maintain consistent measuring procedure and therefore increase the reliability of test results. Small scaled suction bucket foundation was fabricated to represent the commercial support structure installation mechanism and two cases(free-free, free-fixed) of dynamic tests were performed at workshop. From the tests, the importance of dynamic properties of connection part between suction bucket and tower was figured out. More over, types and configuration of measuring devices are recommended which can help find the natural frequency of wind turbine foundation correctly. In field test, it was found that the natural frequency of suction bucket foundation was increased linearly with the penetration depth due to the confining effect of ambient soil. Meanwhile, it was not easy to get an enough excitation force with normal impact hammer because the N.F of suction bucket model was in the lower range of 0 Hz ~ 5 Hz. Therefore, new excitation method which has enough force and can excite lower frequency range was devised. This study will help develop safety check procedure of suction bucket foundation in field at each installation stage using the N.F measurement.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1132-1135
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• 2008

In this study, a circular and indoor soil tank foundation was manufactured to study the improvement according to the degree of turbulence arising from PBD penetration, using the existing plate-type shoe and improved V-type shoe to change the degree of turbulence. Furthermore, to study the foundation improvement effect, the strength, settlement speed in the turbulence area were compared according to the shoe penetration. The results of the study showed that the V-type shoe reduced the strength coefficient decrease effect, and the foundation improvement effect according to the degree of turbulence was identified.

• 한국수자원학회논문집
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• 제33권4호
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• pp.385-392
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• 2000

교각과 기초로 구성되는 불균일단면교각 주위의 사석보호공의 거동에 관련된 인자들의 영향에 관한 실험결과가 기술된다. 불균일단면교각은 교각의 전 길이에 대한 단면이 일정하지 않고 직경 bp의 원주가 보다 큰 직경 bf인 기초에 설치된 구조이다. 사석보호공의 안정은 기초의 높이에 따라 크게 영향을 받으며 한계기초높이, Zc가 존재함이 밝혀졌다. 한계기초높이는 균일단면교각의 한계유속과 같은 한계유속을 갖는 불균일단면교각의 기초높이로 정의되고 실험결과 Zc=0.8bf로 밝혀진다. 기초높이가 Zc보다 작으면 기초의 상류연장으로 작용하여 사석보호공은 더 안정하게 되고, 기초높이가 Zc보다 크게 되면 기초는 단면이 증대된 교각으로 작용하고 기초 자체의 하강류로 인하여 사석보호공은 불안정하게 되어 쉽게 움직이게 된다. 기초상단면적의 영향과 불균일단면교각의 사석보호공의 크기 결정방법이 또한 기술된다.

• Structural Engineering and Mechanics
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• 제58권5호
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• pp.887-903
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• 2016

This study analyses the seismic response of a three-dimensional (3-D) rigid massless square foundation resting or embedded in a viscoelastic soil limited by rigid bedrock. The foundation is subjected to harmonic oblique seismic waves P, SV, SH and R. The key step is the characterization of the soil-foundation interaction by computing the impedance matrix and the input motion matrix. A 3-D frequency boundary element method (BEM) in conjunction with the thin layer method (TLM) is adapted for the seismic analysis of the foundation. The dynamic response of the rigid foundation is solved from the wave equations by taking into account the soil-foundation interaction. The solution is formulated using the frequency BEM with the Green's function obtained from the TLM. This approach has been applied to analyze the effect of soilstructure interaction on the seismic response of the foundation as a function of the kind of incident waves, the angles of incident waves, the wave's frequencies and the embedding of foundation. The parametric results show that the non-vertical incident waves, the embedment of foundation, and the wave's frequencies have important impact on the dynamic response of rigid foundations.

• Journal of Dairy Science and Biotechnology
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• 제23권2호
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• pp.135-141
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• 2005

• 한국유가공학회:학술대회논문집
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• 한국유가공기술과학회 2005년도 창립 30주년 기념 국제심포지움 - 웰빙시대의 우유.유제품의 새로운 발견
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• pp.85-106
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• 2005