• Title/Summary/Keyword: Strength1 Assessment

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Finite Element and Experimental Validation of SINTAP Defect Assessment Procedure for Welded Structure (수치해석과 실험에 의한 SINTAP 용접 구조물 균열 평가법의 검증)

  • 김윤재;김진수
    • Journal of Welding and Joining
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    • v.22 no.1
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    • pp.50-57
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    • 2004
  • This paper provides FE and experimental validation of the defect assessment method for strength mismatched welded structures, resulting from the Brite Euram SINTAP (Structural Integrity Assessment Procedures for European Industry) project. This shows that the proposed method is conservative, and that the degree of conservatism is similar to that embedded in the methods for homogeneous structures. It provides confidence in the use of the proposed SINTAP method for assessing defective weld strength mismatched structures.

Statistical Estimation of Specified Concrete Strength by Applying Non-Destructive Test Data (비파괴시험 자료를 적용한 콘크리트 기준강도의 통계적 추정)

  • Paik, Inyeol
    • Journal of the Korean Society of Safety
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    • v.30 no.1
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    • pp.52-59
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    • 2015
  • The aim of the paper is to introduce the statistical definition of the specified compressive strength of the concrete to be used for safety evaluation of the existing structure in domestic practice and to present the practical method to obtain the specified strength by utilizing the non-destructive test data as well as the limited number of core test data. The statistical definition of the specified compressive strength of concrete in the design codes is reviewed and the consistent formulations to statistically estimate the specified strength for assessment are described. In order to prevent estimating an unrealistically small value of the specified strength due to limited number of data, it is proposed that the information from the non-destructive test data is combined to that of the minimum core test data. The the sample mean, standard deviation and total number of concrete test are obtained from combined test data. The proposed procedures are applied to an example test data composed of the artificial numerical values and the actual evaluation data collected from the bridge assessment reports. The calculation results show that the proposed statistical estimation procedures yield reasonable values of the specified strength for assessment by applying the non-destructive test data in addition to the limited number of core test data.

Durability Assessment of a Control Arm Using 1/4 Car Test (1/4차량 시험을 통한 상부 컨트롤 암의 내구성 평가)

  • Ha, Min-Soo;Son, Hwan-Jung;Kim, Jong-Kyu;Park, Young-Chul
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.9 no.6
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    • pp.16-20
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    • 2010
  • This study proposes a structural design method for the upper control arm installed at the rear side of a SUV. The weight of control arm can be reduced by applying the design. In this research, the former includes optimization technology, and the latter the technologies for selecting aluminum as a steel-substitute material. Strength assessment is the most important design criterion in the structural design of a control arm. At the proto design stage of a new control arm, FE (finite element) analysis is often utilized to predict its strength. In this study, the kriging interpolation method is adopted to obtain the minimum weight satisfying the strength constraint and durability criteria. The optimum results determined from the in-house program are compared with those of ANSYS WORKBENCH. The durability assessment is obtained by a index of fatigue durability and trial & error method, MSC. Fatigue program.

Strength assessment method of ice-class propeller under the design ice load condition

  • Ye, L.Y.;Guo, C.Y.;Wang, C.;Wang, C.H.;Chang, X.
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.11 no.1
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    • pp.542-552
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    • 2019
  • The strength assessment is the most important part at the design of ice-class propeller. Based on ice rules for ice-class propeller in IACS URI3 and FEM, the strength assessment method of ice-class propeller is established in this paper. To avoid the multifarious meshing process of propeller blade, an automatic meshing method has been developed by dividing the propeller geometry into a number of 8-node hexahedron elements along radial, chordwise and thickness directions, then the loaded areas in five cases can easily be calculated and identified. The static FEM is applied to calculate the stress and deformation of propeller blade. The fair agreements between the results of the present method and ANSYS/Workbench demonstrate its robust and the feasibility, and also the method is able to produce smooth gradient field. The blade stress and deformation distributions for five load cases are studied, and then the strength of the whole blade is checked.

The Hull Strength Assessment for Heavy Lift Floating Crane (초대형 해상 크레인의 선체구조 강도평가)

  • Kang, Yong-Gu;Baek, Seung-Hun;Lee, Joon-Hyuk;Park, Woo-Jin;Shim, Dae-Sung;An, Yong-Taek;Cho, Pyung-Sham
    • Special Issue of the Society of Naval Architects of Korea
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    • 2015.09a
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    • pp.1-8
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    • 2015
  • In general, the strength assessment for heavy lift vessel is carried out under two stages. The first stage is to comply with the requirement of KR (Korean Register of Shipping) Steel Barges and Rules for Classification of Steel Ships. At the second stage, the structural strength analysis by Finite Element Method is peformed. This paper describes the strength assessment considering various loads for the heavy lift vessel of sheerleg type.

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An Assessment on the Ultimate Strength of Welding Joint by the Effect of External Force (外力의 效果를 고려한 熔接部의 最終强度에 대한 評價)

  • Bang, Han-Seo;Cha, Yong-Hun;O, U-Seok
    • Journal of Ocean Engineering and Technology
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    • v.9 no.2
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    • pp.20-29
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    • 1995
  • When structures are constructed by welding, structural elements are always accompained by welding residual stress and deformation. Therefore, when the rigidity and strength of the welded structures is considered, it is very important to have sufficient information about the effect of initial deflection and welding residual stress on them. In this paper, the square plates with welding residual stress under compression are dealt with; First, heat conduction and thermal elastic-plastic problems are analyzed by finite element method using 4-node isoparametric elements for assessment on the ultimate strength of welding joint. Later, the ultimate strength of welding joint is assessed by examining the effect of changed type of loading. The specimens are 500{\times}$500mm(a/b=1) and 750{\times}$500mm(a/b=1.5) rectangular plates of whichthicknesses is 9.0mm and simply supported plates getting axiul load in each direction.

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A Study on Evaluation Techniques of Characteristic Strength of Concrete in Existing Structures (실존 콘크리트 구조물의 특성강도 추정기법에 관한 연구)

  • 권영웅;정성철;이상윤;김민수;김인식;이지은
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.04b
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    • pp.703-706
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    • 1998
  • Primarily, to evaluate the structural condition assessment of concrete structures, percentile strength of concrete in concrete structures should be found out. This study aims to establish the evaluation techniques for concrete strength in existing concrete structures considering the concrete quality and reliability. The results are as follows ; 1. Percentile strength of concrete in concrete structures can be estimated from following strength equation. $$f_p=f_{mea} - {\lambda}_pS_s$$2. For the calibration of above percentile strength equation with proposed codes or specifications, following sample size based on ASTM E122 can be applied.

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Numerical Bayesian updating of prior distributions for concrete strength properties considering conformity control

  • Caspeele, Robby;Taerwe, Luc
    • Advances in concrete construction
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    • v.1 no.1
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    • pp.85-102
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    • 2013
  • Prior concrete strength distributions can be updated by using direct information from test results as well as by taking into account indirect information due to conformity control. Due to the filtering effect of conformity control, the distribution of the material property in the accepted inspected lots will have lower fraction defectives in comparison to the distribution of the entire production (before or without inspection). A methodology is presented to quantify this influence in a Bayesian framework based on prior knowledge with respect to the hyperparameters of concrete strength distributions. An algorithm is presented in order to update prior distributions through numerical integration, taking into account the operating characteristic of the applied conformity criteria, calculated based on Monte Carlo simulations. Different examples are given to derive suitable hyperparameters for incoming strength distributions of concrete offered for conformity assessment, using updated available prior information, maximum-likelihood estimators or a bootstrap procedure. Furthermore, the updating procedure based on direct as well as indirect information obtained by conformity assessment is illustrated and used to quantify the filtering effect of conformity criteria on concrete strength distributions in case of a specific set of conformity criteria.

Fatigue Strength Assessment of A Longitudinal Hatch Coaming in a 3800 TEU Containership by ABS Dynamic Approach

  • Cui, Weicheng;Yang, Chunwen;Hu, Jiajun
    • Journal of Ship and Ocean Technology
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    • v.3 no.4
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    • pp.35-51
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    • 1999
  • Fatigue strength assessment procedures have been implemented in the ship design rules by many classification societies. However, a large variation tin the details of the different approaches exists in practically all aspects influding load history assessment, stress evaluation and fatigue strength assessment. In order to assess the influences of thesd variations on the prediction of fatigue lives. a comparative study is organized by the ISSC Committee III.2 Fatigue and Fracture. A pad detail on the top of longitudinal hatch coaming of a panamax container vessel is selected for fatigue calculation. The work described in this paper is one set of results of this comparative study in which the ABS dynamics approach is applied. Through this analysis the following conclusions can be drawn. (1) With the original ABS approach, the fatigue life of this pad detail is very low, only 2.398 years. (2) The treatment of the stillwater bending moment in the ABS approach might be a source of conservatism. If the influence of stillwater bending moment is ignored, then the fatigue life for this pad detail is 7.036 years. (3) The difference between the nominal stress approach and the hot spot stress approach for this pad detail is about 26%.

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Comparisons of Test-Retest Reliability of Strength Measurement of Gluteus Medius Strength between Break and Make Test in Subjects with Pelvic Drop

  • Jeon, In-Cheol
    • The Journal of Korean Physical Therapy
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    • v.31 no.3
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    • pp.147-150
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    • 2019
  • Purpose: The purpose of this study was to compare the reliability of unilateral hip abductor strength assessment in side-lying with break and make test in subjects with pelvic drop. Hip abduction muscles are very important in the hip joint structures. Therefore, it is essential to evaluate their strength in a reliable way. Methods: Twenty-five subjects participated in this study. Unilateral isometric hip abductor muscle strength was measured in side-lying, with use of a specialized tensiometer using smart KEMA system for make test, of a hand held dynamometer for break test. Coefficients of variation, and intra class correlation coefficients were calculated to determine test-retest reliability of hip abductor strength. Results: In make test, maximal hip abductor strength in the side-lying position was significantly higher compared with break test (p<0.05). Additionally, Test-retest reliability of hip abductor strength measurements in terms of coefficients of variation (3.7% for make test, 16.1% for break test) was better in the side-lying position with make test. All intraclass correlation coefficients with break test were lower than make test (0.90 for make test, 0.73 for break test). Conclusion: The side-lying body position with make test offers more reliable assessment of unilateral hip abductor strength than the same position with break test. Make test in side-lying can be recommended for reliable measurement of hip abductor strength in subjects with pelvic drop.