• Title/Summary/Keyword: Incremental formulation

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Linear and Nonlinear Stability Analysis of Shells Using Degenerated Isoparametric Elements (등매개(等媒介) 변수요소(變數要素)를 이용한 쉘의 선형(線形) 및 비선형(非線形) 안정해석(安定解析))

  • Lee, Nam Ho;Choi, Chang Koan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.7 no.2
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    • pp.21-28
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    • 1987
  • The paper describes the analysis of large displacement problems including instability phenomena. The element used in this is a degenerated isoparametric shell element with eight nodes. Total Lagrangian formulation has been adopted in this study using Newton-Raphson iteration method with incremental load. The linear stability analyses performed usually for the initial position can be repeated at several advanced fundamental states on the non-linear buckling path. Thus a current estimate of the failure load is given. The numerical examples of a cylindrical panel under uniform load, simply supported plate under axial load, and clamped plate under uniform load are carried out. The examples applying degenerated isoparametric elements to bifurcation buckling and nonlinear collapse problems are also performed.

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Large deflection analysis of laminated composite plates using layerwise displacement model

  • Cetkovic, M.;Vuksanovic, Dj.
    • Structural Engineering and Mechanics
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    • v.40 no.2
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    • pp.257-277
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    • 2011
  • In this paper the geometrically nonlinear continuum plate finite element model, hitherto not reported in the literature, is developed using the total Lagrange formulation. With the layerwise displacement field of Reddy, nonlinear Green-Lagrange small strain large displacements relations (in the von Karman sense) and linear elastic orthotropic material properties for each lamina, the 3D elasticity equations are reduced to 2D problem and the nonlinear equilibrium integral form is obtained. By performing the linearization on nonlinear integral form and then the discretization on linearized integral form, tangent stiffness matrix is obtained with less manipulation and in more consistent form, compared to the one obtained using laminated element approach. Symmetric tangent stiffness matrixes, together with internal force vector are then utilized in Newton Raphson's method for the numerical solution of nonlinear incremental finite element equilibrium equations. Despite of its complex layer dependent numerical nature, the present model has no shear locking problems, compared to ESL (Equivalent Single Layer) models, or aspect ratio problems, as the 3D finite element may have when analyzing thin plate behavior. The originally coded MATLAB computer program for the finite element solution is used to verify the accuracy of the numerical model, by calculating nonlinear response of plates with different mechanical properties, which are isotropic, orthotropic and anisotropic (cross ply and angle ply), different plate thickness, different boundary conditions and different load direction (unloading/loading). The obtained results are compared with available results from the literature and the linear solutions from the author's previous papers.

Perceived Distribution Quality Awareness, Organizational Culture, TQM on Quality Output

  • ISNAINI, Dewi Budhiartini Juli;DANILWAN, Yuris;MANSUR, Daduk Merdika;ILYAS, Gunawan Bata;MURTINI, Sri;TAUFAN, Muhammad Ybnu
    • Journal of Distribution Science
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    • v.19 no.12
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    • pp.1-14
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    • 2021
  • Purpose: For the last few decades, TQM has become a hot topic in the inner-disciplinary field in the production management line. Still, unfortunately, the study of TQM and Quality Output management is partially only attached to the tangible side in the production management line. Whereas theoretically, the implications of TQM require incremental improvement in all management lines (e.g., HRM, Marketing, Operations, and Distribution Management). Therefore, starting from the main problem, this study aims to analyze the effect of total quality management, Organizational Culture, Perceived Distribution of Quality Awareness, and quality output through a more in-depth analysis. Research design, data and methodology: We conducted a survey of 170 respondents from managers, staff, and employees from 48 companies in Indonesia. We used a quantitative approach with the SEM method to answer this study's problem formulation and hypotheses. Results: The results of our research stated that based on the demonstration of statistical test results, all hypotheses were positive and significant, both direct and indirect relationship demonstrations. Conclusions: Universally, the findings in this study illustrate that the supporting factor for creating value-added in TQM and Quality output lies in the optimal and positive organizational culture and Perceived Distribution Quality Awareness factors in the organization.

Curved-quartic-function elements with end-springs in series for direct analysis of steel frames

  • Liu, Si-Wei;Chan, Jake Lok Yan;Bai, Rui;Chan, Siu-Lai
    • Steel and Composite Structures
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    • v.29 no.5
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    • pp.623-633
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    • 2018
  • A robust element is essential for successful design of steel frames with Direct analysis (DA) method. To this end, an innovative and efficient curved-quartic-function (CQF) beam-column element using the fourth-order polynomial shape function with end-springs in series is proposed for practical applications of DA. The member initial imperfection is explicitly integrated into the element formulation, and, therefore, the P-${\delta}$ effect can be directly captured in the analysis. The series of zero-length springs are placed at the element ends to model the effects of semi-rigid joints and material yielding. One-element-per-member model is adopted for design bringing considerable savings in computer expense. The incremental secant stiffness method allowing for large deflections is used to describe the kinematic motion. Finally, several problems are studied in this paper for examining and validating the accuracy of the present formulations. The proposed element is believed to make DA simpler to use than existing elements, which is essential for its successful and widespread adoption by engineers.

Analysis of shallow footings rested on tensionless foundations using a mixed finite element model

  • Lezgy-Nazargah, M.;Mamazizi, A.;Khosravi, H.
    • Structural Engineering and Mechanics
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    • v.81 no.3
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    • pp.379-394
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    • 2022
  • Shallow footings usually belonged to the category of thick plate structures. For accurate analysis of thick plates, the contribution of out-of-plane components of the stress tensor should be considered in the formulation. Most of the available shallow footing models are based on the classical plate theories, which usually neglect the effects of the out-of-plane stresses. In this study, a mixed-field plate finite element model (FEM) is developed for the analysis of shallow footings rested on soil foundations. In addition to displacement field variables, the out-of-plane components of the stress tensor are also assumed as a priori unknown variables. For modeling the interaction effect of the soil under and outside of the shallow footings, the modified Vlasov theory is used. The tensionless nature of the supporting soil foundation is taken into account by adopting an incremental, iterative procedure. The equality requirement of displacements at the interface between the shallow footing and soil is fulfilled using the penalty approach. For validation of the present mixed FEM, the obtained results are compared with the results of 3D FEM and previous results published in the literature. The comparisons show the present mixed FEM is an efficient and accurate tool for solving the problems of shallow footings rested on subsoil.

Numerical Prediction of Ultimate Strength of RC Beams and Slabs with a Patch by p-Version Nonlinear Finite Element Modeling and Experimental Verification (p-Version 비선형 유한요소모델링과 실험적 검증에 의한 팻취 보강된 RC보와 슬래브의 극한강도 산정)

  • Ahn Jae-Seok;Park Jin-Hwan;Woo Kwang-Sung
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.17 no.4
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    • pp.375-387
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    • 2004
  • A new finite element model will be presented to analyze the nonlinear behavior of RC beams and slabs strengthened by a patch repair. The numerical approach is based on the p-version degenerate shell element including theory of anisotropic laminated composites, theory of materially and geometrically nonlinear plates. In the nonlinear formulation of this model, the total Lagrangian formulation is adopted with large deflections and moderate rotations being accounted for in the sense of von Karman hypothesis. The material model is based on hardening rule, crushing condition, plate-end debonding strength model and so on. The Gauss-Lobatto numerical quadrature is applied to calculate the stresses at the nodal points instead of Gauss points. The validity of the proposed p-version nonlinear finite element model is demonstrated through the load-deflection curves, the ultimate loads, and the failure modes of RC beams or slabs bonded with steel plates or FRP plates compared with available result of experiment and other numerical methods.

Evaluation of Thermal and Shrinkage Stresses in Hardening Concrete Considering Early-Age Creep Effect (초기재령 콘크리트의 크리프를 고려한 온도 및 수축응력 해석)

  • 차수원;오병환;이형준
    • Journal of the Korea Concrete Institute
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    • v.14 no.3
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    • pp.382-391
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    • 2002
  • This study is devoted to the problems of thermal and shrinkage stresses in order to avoid cracking at early ages. The early-age damage induced by volume change has great influence on the long-term structural performance of the concrete structures such as its durability and serviceability To solve this complex problem, the computer programs for analysis of thermal and shrinkage stresses were developed. In these procedures, numerous material models are needed and the realistic numerical models have been developed and validated by comparison with relevant experimental results in order to solve practical problems. A framework has been established for formulation of material models and analysis with 3-D finite element method. After the analysis of the temperature, moisture and degree of hydration field in hardening concrete structure, the stress development is determined by incremental structural formulation derived from the principle of virtual work. In this study, the stress development is related to thermal and shrinkage deformation, and resulting stress relaxation due to the effect of early-age creep. From the experimental and numerical results it is found that the early-age creep p)ays important role in evaluating the accurate stress state. The developed analysis program can be efficiently utilized as a useful tool to evaluate the thermal and shrinkage stresses and to find measures for avoiding detrimental cracking of concrete structures at early ages.

A Cognitive Psychological Approach to the Pictorial Syntactics (미술구문론의 인지심리학적 접근가능성)

  • Kim Bok-Yoong;Park Byung-Joo
    • Journal of Science of Art and Design
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    • v.3
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    • pp.225-247
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    • 2001
  • The analysis of art work that is objective and theoretical needs the help of the cognitive psychology, for the pictorial semiotics requires psychology. The first step to the analysis of art work is about the visual elements and their relations. But the semiotics is lack of the method of the analysis of art work and the some authors don't have treated or been interested in psychological analysis. The main problem of visual semiotics is the density of pictorial representation. It makes the semantic of art work impossible at the very early process of analysis. But the density is not only a matter of visual representation, verbal language also has this problem. The point is that art work functions more art than denotation, but verbal language does more denotation than art. This difference makes difficult to apply the method of language or semiotics to visual art. The possibility of pictorial syntax or perceptual semantics should begin considering the unification of perception and semantics. In principles these two field can be unified. At atomism and holism these are parallel. Therefore perceptual semantics is possible The cognitive psychology can help to formulation of perceptual semantics. At first, the visual representation is incremental and it can be divided at three steps. In these steps each sensation, perception and cognition level has their own role. Perceptual representation of art work should be specified at these three levels. And each of these levels, the special properties of art work should be drawn and examined in the possibility of semiotics. The investigation of psychological levels and semiotic level should be circulated. It will help to formulate the method of analysis of art work.

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Seismic response of nonstructural components considering the near-fault pulse-like ground motions

  • Zhai, Chang-Hai;Zheng, Zhi;Li, Shuang;Pan, Xiaolan;Xie, Li-Li
    • Earthquakes and Structures
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    • v.10 no.5
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    • pp.1213-1232
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    • 2016
  • This paper investigates the response of nonstructural components in the presence of nonlinear behavior of the primary structure considering the near-fault pulse-like ground motions. A database of 81 near-fault pulse-like ground motions is used to examine the effect of these ground motions on the response of nonstructural components. For comparison, a database of 573 non-pulse-like ground motions selected from the PEER database is also employed. The effects of peak ground velocity (PGV), maximum incremental velocity (MIV), primary structural degrading behavior and damping of nonstructural components are evaluated and discussed statistically. Results are presented in terms of amplification factor which quantifies the effect of inelastic deformations of the primary structure on subsystem responses. The results indicate that the near-fault pulse-like ground motions can significantly increase the amplification factors of nonstructural components with primary structural period and the magnitude of increase can reach 17%. The effect of PGV and MIV on amplification factors tends to increase with the increase of primary structural ductility. The near-fault pulse-like ground motions are more dangerous to components supported by structures with strength and stiffness degrading behavior than ordinary ground motions. A new simplified formulation is proposed for the application of amplification factors for design of nonstructural components for near-fault pulse-like ground motions.

Design of Kinematic Position-Domain DGNSS Filters (차분 위성 항법을 위한 위치영역 필터의 설계)

  • Lee, Hyung Keun;Jee, Gyu-In;Rizos, Chris
    • Journal of Advanced Navigation Technology
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    • v.8 no.1
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    • pp.26-37
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    • 2004
  • Consistent and realistic error covariance information is important for position estimation, error analysis, fault detection, and integer ambiguity resolution for differential GNSS. In designing a position domain carrier-smoothed-code filter where incremental carrier phases are used for time-propagation, formulation of consistent error covariance information is not easy due to being bounded and temporal correlation of propagation noises. To provide consistent and correct error covariance information, this paper proposes two recursive filter algorithms based on carrier-smoothed-code techniques: (a) the stepwise optimal position projection filter and (b) the stepwise unbiased position projection filter. A Monte-Carlo simulation result shows that the proposed filter algorithms actually generate consistent error covariance information and the neglection of carrier phase noise induces optimistic error covariance information. It is also shown that the stepwise unbiased position projection filter is attractive since its performance is good and its computational burden is moderate.

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