• Title/Summary/Keyword: Marine structural element

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Structural damage detection based on changes of wavelet transform coefficients of correlation functions

  • Sadeghian, Mohsen;Esfandiari, Akbar;Fadavie Manochehr
    • Structural Monitoring and Maintenance
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    • v.9 no.2
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    • pp.157-177
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    • 2022
  • In this paper, an innovative finite element updating method is presented based on the variation wavelet transform coefficients of Auto/cross-correlations function (WTCF). The Quasi-linear sensitivity of the wavelet coefficients of the WTCF concerning the structural parameters is evaluated based on incomplete measured structural responses. The proposed algorithm is used to estimate the structural parameters of truss and plate models. By the solution of the sensitivity equation through the least-squares method, the finite element model of the structure is updated for estimation of the location and severity of structural damages simultaneously. Several damage scenarios have been considered for the studied structure. The parameter estimation results prove the high accuracy of the method considering measurement and mass modeling errors.

Structural Safety Evaluation of Marine Loading Arm Using Finite Element Analysis (유한요소해석을 이용한 해양 로딩암의 구조안전성 평가)

  • Song, Chang Yong;Choi, Ha Young;Shim, Seung Hwan
    • Journal of Ocean Engineering and Technology
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    • v.27 no.1
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    • pp.43-50
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    • 2013
  • This paper presents a structural design review of a marine loading arm used for the fluid transfer of a liquid cargo from a ship or offshore plant. The marine loading arm is installed on a ship, offshore plant, or jetty in order to load or unload liquid cargo such as crude oil, liquefied natural gas (LNG), chemical products, etc. The structural design of this marine loading arm is obliged to comply with the design and construction specifications regulated by the oil companies and international marine forum (OCIMF). In this paper, the structural safety of the initial design for the marine loading arm is evaluated for the design load conditions required by various operational modes. The evaluated results based on a finite element analysis (FEA) are reviewed in relation to the OCIMF specifications.

Study of Application of Salt Resistance Concrete Beam Reinforced with Glass Fiber Reinforced Polymer-Ribbed Bar as a Member of Marine Structure (GFRP 보강 내염성 콘크리트 보의 해양구조부재로서의 적용성 검토)

  • Kim, Chung-Ho;Hwang, Yun-Hee
    • Journal of Ocean Engineering and Technology
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    • v.22 no.5
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    • pp.94-99
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    • 2008
  • Three types of salt resistant concrete beams reinforced with glass fiber reinforced polymer-ribbed bars (GFRP-ribbed bars) were selected, and their applicable properties were investigated with the goal of improving the problem of capacity deterioration in marine structures due to sea water corrosion. In this study, the structural behaviors were similar to RC beams in relation to the development of the strength and stiffness up to the generation of the initial crack. After the growth of this initial crack, the structural properties decreased owing to a sudden loss of bond strength. Also these beams showed the trends of brittle failure. As a result, it was confirmed that a GFS beam replaced with Fly Ash (20%) and Silica Fume (5%) has the best application as a marine structural element.

Structural Anaysis of High Pressure Steam Turbine Casings for Power Plants Using the BEM and the FEM (경계요소법과 유한요소법을 이용한 발전용 고압 증기터빈 케이싱의 구조해석)

  • 조종래
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.5
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    • pp.609-616
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    • 1998
  • Structural analyses are preformed for the high pressure steam turbine casings of the nuclear and the fossil power plants. An axisymmetric boundary element program for analysis of the casings is developed and applied in the process of practical structural design. To show the useful-ness and accuracy of the developed program results of the analysis are compared with those of the finite element analysis under hydrostatic test pressure, To check the validity of the axisymmetric numerical analysis of the casings the stresses resulting from the hydrostatic test pressure are measured using the strain gate. The results of the numerical analyses are compared and discussed with those of the experiments.

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A Comparative Study for the Fatigue Assessment of fillet Weldments Using Structural Stress and Hot Spot Stress (필릿 용접구조물의 피로해석을 위한 기준응력에 대한 비교 연구 -구조응력 및 핫스팟응력-)

  • Ha Chung-In;Kang Sung-Won;Kim Man-Soo;Sohn Sang-Yong;Heo Joo-Ho;Kim Myung-Hyun
    • Journal of the Society of Naval Architects of Korea
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    • v.43 no.4 s.148
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    • pp.476-483
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    • 2006
  • Fatigue strength assessments with two types of load carrying fillet weldment under out-of-plane bending load have been carried out by using both hot spot stress and structural stress methods. In this study, a derivation for the structural stress method using shell element models is discussed in detail. Finite element analysis using shell element models have been performed for the assessment of fatigue strength. As a result of the fatigue strength evaluation for load carrying transverse fillet weldment, hot spot stress method is found to be consistent with structural stress method and measurement. Hot spot stress, however, estimated for the load carrying longitudinal fillet weldment exhibit large variation with respect to mesh size and element type while the calculated structural stress for the longitudinal fillet weldment is relatively independent of mesh size. On the other hand, drawbacks and doubts associated with applying the structural stress method such as the guidance of virtual node method have been discussed.

Structural analysis of a Korean-designed cruiser-class sailing yacht

  • Bae, Dong-Myung;Cao, Bo;Kim, Dong-Jun
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.51 no.1
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    • pp.9-15
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    • 2015
  • A Korean-designed cruiser class sailing yacht, based on the form of traditional yachts, has been developed. In this paper, structural design procedures for the yacht are studied. The scantling of structural members and loads is carried out based on the guidelines suggested by Australian Standard 4132-1993, the American Bureau of Shipping (ABS) and the International Organization for Standardization (ISO). Patran/Nastran finite element analysis is performed on models of the trial sailing boat, and from these results, the structural strength of the ship's hull is verified.

Development of Geometrically Nonlinear Finite Element Analysis Examples for Computational Structural Analysis (전산구조해석을 위한 기하학적 비선형 유한요소해석 예제 개발)

  • Na, Won-Bae;Lee, Sun-Min
    • Journal of Fisheries and Marine Sciences Education
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    • v.24 no.5
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    • pp.699-711
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    • 2012
  • An undergraduate course named computational structural analysis becomes more significant in recent years because of its important role in industries and the recent innovation in computer technology. Typically, the course consists of introduction to finite element method, utilization of general purpose finite element software, and examples focusing on static and linear analyses on various structural members such as a beam, truss, frame, arch, and cable. However, in addition to the static and linear analyses, current industries ask graduates to acquire basic knowledge on structural dynamics and nonlinear analysis, which are not listed in the conventional syllabus of the computational structural analysis. Therefore, this study develops geometrically nonlinear examples, which can help students to easily capture the fundamental nonlinear theory, software manipulation, and problem solving skills. For the purpose, five different examples are found, developed for the analyses of cables and cable nets, which naturally have strong geometrical non-linearity. In the paper, these examples are presented, discussed, and finally compared for a better subject development.

Structural Analysis of Axisymmetric Conical Shells Using Finite Element-Transfer Stiffness Coefficient Method (유한요소-전달강성계수법을 이용한 축대칭 원추형 셸의 구조해석)

  • Choi, Myung-Soo;Byun, Jung-Hwan;Yeo, Dong-Jun
    • Journal of Power System Engineering
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    • v.19 no.1
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    • pp.38-44
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    • 2015
  • Various finite elements have been studied and developed to analyze a variety of structures in the finite element method(FEM). The transfer stiffness coefficient method(TSCM) is an effective algorithm for structural analysis but the structures which can be applied were limited. In this paper, a computational algorithm for the structural analysis of axisymmetric conical shells under axisymmetric loading is formulated using the finite element-transfer stiffness coefficient method(FE-TSCM). The basic concept of FE-TSCM is the combination of the modeling technique of FEM and the transfer technique of TSCM. The FE-TSCM has all the advantages of both FEM and TSCM. After carrying out the structural analysis of axisymmetric conical shells using FEM, FE-TSCM, and analytical method we compare the computational results of FE-TSCM with those of the other methods in terms of computational accuracy.