• 제목/요약/키워드: Polytechnic analysis

검색결과 1,109건 처리시간 0.027초

A force-based element for direct analysis using stress-resultant plasticity model

  • Du, Zuo-Lei;Liu, Yao-Peng;Chan, Siu-Lai
    • Steel and Composite Structures
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    • 제29권2호
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    • pp.175-186
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    • 2018
  • The plastic hinge method and the plastic zone method are extensively adopted in displacement-based elements and force-based elements respectively for second-order inelastic analysis. The former enhances the computational efficiency with relatively less accurate results while the latter precisely predicts the structural behavior but generally requires more computer time. The displacement-based elements receive criticism mainly on plasticity dominated problems not only in accuracy but also in longer computer time to redistribute the forces due to formation of plastic hinges. The multi-element-per-member model relieves this problem to some extent but will induce a new problem in modeling of member initial imperfections required in design codes for direct analysis. On the contrary, a force-based element with several integration points is sufficient for material yielding. However, use of more integration points or elements associated with fiber section reduces computational efficiency. In this paper, a new force-based element equipped with stress-resultant plasticity model with minimal computational cost is proposed for second-order inelastic analysis. This element is able to take the member initial bowing into account such that one-element-per-member model is adequate and complied with the codified requirements of direct analysis. This innovative solution is new and practical for routine design. Finally, several examples demonstrate the validity and accuracy of the proposed method.

단상 1MVA 고온초전도 변압기의 누설임피던스 3차원 해석 및 시험 (Test and Analysis of 3-D of Leakage Impedances in a Single-Phase 1MVA HTS Transformer)

  • 김성훈;김우석;이상진;최경달;주형길;홍계원;한진호;한송엽;송희석;박정호
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 B
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    • pp.1003-1005
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    • 2003
  • In this paper, 3-D nonlinear electromagnetic analysis of a single phase 1MVA 22.9 kV/6.6 kV high temperature superconducting(HTS) transformer with double pancake windings was accomplished. The characteristics of 1MVA HTS transformer such as The efficiency, voltage regulation and % impedance voltage drop were obtained by the 3-D non-linear electromagnetic analysis. And in order to verify the 3-D non-linear electromagnetic analysis of a single phase 1MVA HTS transformer, a 1MVA test transformer with windings made of copper tapes with the same size as BSCCO-2223 HTS tape was manufactured. The energy conservation method to perform the analysis of leakage impedances of both a 1MVA HTS transformer and test transformer was used. The characteristic analysis such as efficiency, voltage regulation and % impedance voltage drop of transformer was performed. And the obtained values of both 1MVA HTS transformer and test transformer were compared.

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Comprehensive energy analysis of natural gas transportation in molecules or in electricity

  • Udaeta, Miguel E.M.;Rigolin, Pascoal H.C.;Burani, Geraldo F.;Galvao, Luiz C.R.
    • Advances in Energy Research
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    • 제2권2호
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    • pp.61-72
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    • 2014
  • This paper's aim is to do a global evaluation (considering four dimensions: technical-economic, environmental, social and political) in the ways of natural gas transportation (gas pipelines, GNL and GTL) and electric transmission, in order to supply the energy demands of Mato Grosso do Sul, a brazilian state. The transport ways had been compared between itself using a software of decision taking (Decision Lens Suite), which determined a better way for transporting natural gas in this case. In a generalized manner the gas pipeline is the best way of transporting natural gas, therefore it takes advantage in the majority of the analyzed dimensions.

The Effect of the Pretreatment Print Paste Contents on Colour Yield of an Ink-jet Printed Cotton Fabric

  • Yuen, C.W.M.;Ku, S.K.A.;Choi, P.S.;Kan, C.W.
    • Fibers and Polymers
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    • 제5권2호
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    • pp.117-121
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    • 2004
  • Optimum condition concerning the content of pretreatment print paste and steaming time for ink-jet printing was newly developed through the orthogonal analysis. The cotton fabric treated under the newly developed optimum condition could achieve a high level of colour yield similar to that of the commercially pretreated cotton fabric available in the market for ink-jet printing. The results were discussed thoroughly in this paper.

LED조명에서 MPCB와 FPCB의 방열 성능 비교 연구 (Comparisons of the Heat Dissipation Performances of MPCB and FPCB in LED Lights)

  • 신상묵;문덕영;유경선;현동훈
    • 한국생산제조학회지
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    • 제26권4호
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    • pp.371-377
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    • 2017
  • In this study, the heat dissipation performances of metal printed circuit boards (MPCBs) and flexible printed circuit boards (FPCBs) used in light-emitting diode (LED) lights were compared and analyzed by performing a heat dissipation simulation using a thermal flow analysis program. The results were summarized graphically. The temperature distribution of the MPCB was found to be better than that of the FPCB, indicating the better heat dissipation performance of the MPCB. For the two FPCB structures studied, we confirmed the LED temperature and temperature distribution by thermal flow analysis and found that for better overall heat dissipation performance, PCBs should preferably have an asymmetric structure. We confirmed the possibility of using FPCBs, which are characterized by a flexible structure, for LED lighting.

Features of the Impact of Social and Digital Changes on the System of Government Regulation of Banking Activity

  • Zalutska, Khrystyna;Pasichnyk, Vаsyl;Smolinska, Natalia;Grybyk, Igor;Antonova, Liudmyla
    • International Journal of Computer Science & Network Security
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    • 제22권4호
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    • pp.217-222
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    • 2022
  • The main purpose of the article is to study the features of the impact of social and digital changes on the system of government regulation of banking acitivity. The digital economy sets the vector along which socio-economic systems of micro-, meso-, macro-levels will develop in the long term, which necessitates research and a comprehensive analysis of digital transformation processes. Once a priority for individual innovative companies, today digital transformation has become a mass phenomenon, and the corresponding projects are vital for the success of not only individual companies, but also regions and countries. At the same time, this transformation itself is closely connected with the trend of servicing socio-economic systems and is largely implemented on its basis. Moreover, this relationship and the mechanism for its implementation remain insufficiently studied, which necessitates the development of tools for its identification, assessment and management. As a result of the analysis, the key aspects of the impact of social and digital changes on the system of state regulation of banking activities were identified.

신발 설계 및 평가를 위한 컴퓨터 모델 (REVIEW OF COMPUTATIONAL MODELS FOR FOOTWEAR DESIGN AND EVALUATION)

  • Cheung, Jason Tak-Man;Yu, Jia;Zhang, Ming
    • 한국운동역학회지
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    • 제19권1호
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    • pp.13-25
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    • 2009
  • Existing footwear biomechanics studies rely on simplified kinetics and kinematics, plantar pressure and muscle electromyography measurements. Because of the complexity of foot-shoe interface and individualized subject response with different footwear, consistent results regarding the biomechanical performance of footwear or footwear components can yet be achieved. The computational approach can be an efficient and economic alternative to study the biomechanical interactions of foot and footwear. Continuous advancement in numerical techniques as well as computer technology has made the finite element method a versatile and successful tool for biomechanics researchdue to its capability of modelling irregular geometrical structures, complex material properties, and complicated loading and boundary conditions. Finite element analysis offers asystematic and economic alternative in search of more in-depth biomechanical information such as the internal stress and strain distributions of foot and footwear structures. In this paper, the current establishments and applications of the computational approach for footwear design and evaluation are reviewed.

A Study on Sensitivity Analysis for Process Parameters in GMA Welding Processes

  • Kim, Ill-Soo;Park, Chang-Eun;An, Young-Ho;Park, Ju-Seog;Chon, Kwang-Suk;Jeong, Young-Jae
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2003년도 춘계학술발표대회 개요집
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    • pp.29-31
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    • 2003
  • Generally, the Quality of a weld joint is strongly influenced by process parameters during the welding process. In order to achieve high quality welds, mathematical models that can predict the bead geometry to accomplish the desired mechanical properties of the weldment should be developed. To achieve this objectives, a sensitivity analysis has been conducted and compared the relative impact of three process parameters on bead geometry in order to verify the measurement errors on the values of the uncertainty in estimated parameters. The results obtained show that developed mathematical models can be applied to estimate the effectiveness of process parameters for a given bead geometry, and a change of process parameters affects the bead width and bead height more strongly than penetration relatively.

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Response prediction of a 50 m guyed mast under typhoon conditions

  • Law, S.S.;Bu, J.Q.;Zhu, X.Q.;Chan, S.L.
    • Wind and Structures
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    • 제9권5호
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    • pp.397-412
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    • 2006
  • This paper presents the wind excited acceleration responses of a 50 m guyed mast under the action of Typhoon Dujuan. The response of the structure is reconstructed from using a full finite element model and an equivalent beam-column model. The wind load is modelled based on the measured wind speed and recommendations for high-rise structures. The nonlinear time response analysis is conducted using the Newton Raphson iteration procedure. Comparative studies on the measured and computed frequencies and acceleration responses show that the torsional vibration of the structure is significant particularly in the higher vibration modes after the first few bending modes. The equivalent model, in general, gives less accurate amplitude predictions than the full model because of the omission of torsional stiffness of the mast in the vibration analysis, but the root-mean-square value is close to the measured value in general with an error of less than 10%.

SIMPLIFYING AND FINDING ORDINARY DIFFERENTIAL EQUATIONS IN TERMS OF THE STIRLING NUMBERS

  • Qi, Feng;Wang, Jing-Lin;Guo, Bai-Ni
    • Korean Journal of Mathematics
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    • 제26권4호
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    • pp.675-681
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    • 2018
  • In the paper, by virtue of techniques in combinatorial analysis, the authors simplify three families of nonlinear ordinary differential equations in terms of the Stirling numbers of the first kind and establish a new family of nonlinear ordinary differential equations in terms of the Stirling numbers of the second kind.