• 제목/요약/키워드: Non-Linear theory.

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Non-linear analysis of dealamination fracture in functionally graded beams

  • Rizov, Victor I.
    • Coupled systems mechanics
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    • v.6 no.1
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    • pp.97-111
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    • 2017
  • The present paper reports an analytical study of delamination fracture in the Mixed Mode Flexure (MMF) functionally graded beam with considering the material non-linearity. The mechanical behavior of MMF beam is modeled by using a non-linear stress-strain relation. It is assumed that the material is functionally graded along the beam height. Fracture behavior is analyzed by the J-integral approach. Non-linear analytical solution is derived of the J-integral for a delamination located arbitrary along the beam height. The J-integral solution derived is verified by analyzing the strain energy release rate with considering the non-linear material behavior. The effects of material gradient, crack location along the beam height and material non-linearity on the fracture are evaluated. It is found that the J-integral value decreases with increasing the upper crack arm thickness. Concerning the influence of material gradient on the non-linear fracture, the analysis reveals that the J-integral value decreases with increasing the ratio of modulus of elasticity in the lower and upper edge of the beam. It is found also that non-linear material behavior leads to increase of the J-integral value. The present study contributes for the understanding of fracture in functionally graded beams that exhibit material non-linearity.

A Study on rapid evaluation of reliability for acyclic non-linear graph (Acyclic non-linear graph의 빠른 신뢰도 계산방법에 관한 연구)

  • 이광원;이현규
    • Journal of the Korean Society of Safety
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    • v.13 no.2
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    • pp.136-144
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    • 1998
  • FTA is the most commonly used method among quantitative safety assessment. In case that the observing system become larger, a lot of terms should be calculated to accomplish FTA through complicated process. Many methods have been tried to reduce time, one of tries is How to calculate the reliability using graph theory after changing W to graph. This paper suggests an algorithm that can calculate more rapidly reliability and outset of system expressed by non-linear graph as like as FTA or CCA.

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Non-linear study of mode II delamination fracture in functionally graded beams

  • Rizov, Victor I.
    • Steel and Composite Structures
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    • v.23 no.3
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    • pp.263-271
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    • 2017
  • A theoretical study was carried-out of mode II delamination fracture behavior of the End Loaded Split (ELS) functionally graded beam configuration with considering the material non-linearity. The mechanical response of ELS was modeled analytically by using a power-law stress-strain relation. It was assumed that the material is functionally graded transversally to the beam. The non-linear fracture was investigated by using the J-integral approach. Equations were derived for the crack arm curvature and zero axes coordinate that are needed for the J-integral solution. The analysis developed is valid for a delamination crack located arbitrary along the beam height. The J-integral solution was verified by analyzing the strain energy release rate with considering material non-linearity. The effects of material gradient, non-linear material behavior and crack location on the fracture were evaluated. The solution derived is suitable for parametric analyses of non-linear fracture. The results obtained can be used for optimization of functionally graded beams with respect to their mode II fracture performance. Also, such simplified analytical models contribute for the understanding of delamination fracture in functionally graded beams exhibiting material non-linearity.

Gemetrical Non-Linear Behavior of Simply Supported Tapered Beams (단순지지 변단면 보의 기하학적 비선형 거동)

  • 이병구
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.41 no.1
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    • pp.106-114
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    • 1999
  • This paper explores the geometrical non-linear behavior of the simply supported tapered beams subject to the trapezoidal distributed load and end moments. In order to apply the Bernoulli -Euler beam theory to this tapered beam, the bending moment equation on any point of the elastical is obtained by the redistribution of trapezoidal distributed load. On the basis of the bending moment equation and the BErnoulli-Euler beam theory, the differential equations governging the elastical of such beams are derived and solved numerically by using the Runge-Jutta method and the trial and error method. The three kinds of tapered beams (i.e. width, depth and square tapers) are analyzed in this study. The numerical results of non-linear behavior obtained in this study from the simply supported tapered beams are appeared to be quite well according to the results from the reference . As the numerical results, the elastica, the stress resultants and the load-displacement curves are given in the figures.

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Non-Linear Behavior of Tapered Beams with Clamped-Roller Ends, subjected to a Concentrated Load (집중하중을 받는 변단면 고정-이동지점 보의 비선형 거동)

  • 이병구;이종국;최규문;김무영
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2000.10a
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    • pp.201-208
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    • 2000
  • This paper explores the non-linear behavior of tapered beam subjected to a floating concentrated load. For applying the Bernoulli-Euler beam theory to this beam, the bending moment at any point of elastica is obtained from the final equilibrium state. By using the bending moment equation and the Bernoulli-Euler beam theory, the differential equations governing the elastica of clamped-roller beam are derived, and solved numerically. Three kinds of tapered beam types are considered. The numerical results of the non-linear behavior obtained in this study are agreed quite well to the results obtained from the laboratory-scale experiments.

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Non-Linear Behavior of Tapered Simple Beam with a Floating Concentrated Load (변화위치 집중하중을 받는 변단면 단순보의 비선형 거동)

  • 이병구
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.42 no.2
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    • pp.108-114
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    • 2000
  • This paper explores the non-linear behavior of tapered beam subjected to a floating concentration load. For applying the Bernoulli-Euler beam theory to this beam, the bending moment at any point of elastical is obtained from the final equilibrium stage. By using the bending moment equation and the Bernoulli-Euler beam theory, the differential equations governing the elastica of simple beam are derived , and solved numberically . Three kinds of tapered beam types are considered . The numerical results of the non-linear behavior obtained in this study are agreed quite well to the results obtained from the laboratory-scale experiments.

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Classification of Service Attributes and Strategic Customer Service Management based on the Asymmetric and Non-linear Relationship between Service Attributes and Customer Satisfaction (서비스 속성과 고객만족과의 비대칭적, 비선형적 관계에 근거한 서비스 속성 분류와 전략적 고객서비스 경영)

  • Park, Jung-Young;Lee, Gye-Hee
    • Journal of the Korean Society of Food Culture
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    • v.23 no.5
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    • pp.605-615
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    • 2008
  • The principal objective of this study was to categorize service attributes on the basis of the asymmetric and non-linear relationship existing between service attributes and customer satisfaction. Researchers generally assume that service attribute performances and customer satisfaction are both symmetrical and linear. That is to say, improvements in attribute performance will inevitably result in increased customer satisfaction. However, this is not always the case. Certain attributes have been shown not to create satisfaction even when improved, and others do not create dissatisfaction even when their performance ratings become negative. Understanding this relationship is crucial not only to researchers, but also to service managers. Service managers can arrange their priorities with regard to which attributes must be improved or promoted first, in an environment of limited technical, financial, and human resources. Many studies into this asymmetric and non-linear relationship have recently been conducted, beginning with Herzberg's motivation-hygiene theory (1976) and the disconfirmation theory, which was eventually developed into Kano's model (1984). This study attempted to determine the impact level of service attributes on incidents of satisfaction or dissatisfaction. It used 30 service attributes generated by Park (2008) in the CIT research into family restaurants. The data were collected from 600 participants, 300 incidences of satisfaction and 300 incidents of dissatisfaction, via an online survey. The t-test was used to confirm the difference between the satisfaction group's and dissatisfaction group's attributes. 11 attributes were found to be significant at a level of p>0.05. This indicates that the 11 attributes exerted different impacts on satisfaction and dissatisfaction, which confirmed the asymmetric and non-linear relationship. 14 attributes were categorized into the core service, 1 attribute into the quality service, 7 attributes into the basic service, and 8 attributes into the neutral service. Strategic customer service management was recommended for the 'A' family restaurant as an example, on the basis of the asymmetric and non-linear relationship and the characteristics of the four service factors.

Investigation of nonlinear free vibration of FG-CNTRC cylindrical panels resting on elastic foundation

  • J.R. Cho
    • Structural Engineering and Mechanics
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    • v.88 no.5
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    • pp.439-449
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    • 2023
  • Non-linear vibration characteristics of functionally graded CNT-reinforced composite (FG-CNTRC) cylindrical shell panel on elastic foundation have not been sufficiently examined. In this situation, this study aims at the profound numerical investigation of the non-linear vibration response of FG-CNTRC cylindrical panels on Winkler-Pasternak foundation by introducing an accurate and effective 2-D meshfree-based non-linear numerical method. The large-amplitude free vibration problem is formulated according to the first-order shear deformation theory (FSDT) with the von Karman non-linearity, and it is approximated by Laplace interpolation functions in 2-D natural element method (NEM) and a non-linear partial derivative operator HNL. The complex and painstaking numerical derivation on the curved surface and the crucial shear locking are overcome by adopting the geometry transformation and the MITC3+ shell elements. The derived nonlinear modal equations are iteratively solved by introducing a three-step iterative solving technique which is combined with Lanczos transformation and Jacobi iteration. The developed non-linear numerical method is estimated through the benchmark test, and the effects of foundation stiffness, CNT volume fraction and functionally graded pattern, panel dimensions and boundary condition on the non-linear vibration of FG-CNTRC cylindrical panels on elastic foundation are parametrically investigated.

A Study on the Non-linear Relationship between Asymmetric Interdependence and Conflict (불균형적 상호의존성과 갈등간 비선형적 관계에 대한 연구)

  • Kim, Jong-Keun;Kim, Jae-Wook
    • Journal of Distribution Research
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    • v.10 no.2
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    • pp.49-72
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    • 2005
  • As interdependence and conflict are important to the understanding of channel interactions, many researchers have studied their relationship. Identifying the relationship between interdependence and conflict will help understanding an exchange relationship. In social science, the relationship between interdependence and conflict is explained by two contradictory theories, and there are also inconsistent results in marketing science. The authors suggest non-linear relations between asymmetric interdependence and conflict, based on bilateral deterrence theory and conflict spiral theory. Using survey data from industrial market, we demonstrate that there is an inverted U-shaped relationship between asymmetric interdependence and interfirm conflict. The result show, as the magnitude of interdependence is high. the hypothesis on the non-linear relationship between asymmetric interdependence and conflicts is acceptable on both suppliers and distributors. Finally, we discuss several theoretical implications and suggest limitations and future research issues.

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Dynamic Analysis of Steel Jackets under Wave and Earthquake Loadings I : Linear and Non-linear F. E. Formulation (파랑 및 지진하중을 받는 스틸자켓의 동적해석 I : 선형 및 비선형 유한요소 정식화)

  • 김문영;백인열;고진석
    • Journal of the Earthquake Engineering Society of Korea
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    • v.5 no.5
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    • pp.1-11
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    • 2001
  • The purpose of this study is to develop the main program and pre/post processor for the geometric and plastic non-linear analysis of steel jacket structures subjected to wave and earthquake loadings. In this paper, steel jackets are modelled using geometric non-linear space frames and wave loadings re evaluated based on Morrison equation using the linear Airy theory and the fifth Stokes theory. Random wave is generated using JONSWAP spectrum. For earthquake analysis, dynamic analysis is performed using artificial earthquake time history. Also the plastic hinge method is presented for limit analysis of steel jacket. In the companion paper, the pre/post processor is developed and the numerical examples are presented for linear and non-linear dynamic analysis of steel jackets.

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