• Title/Summary/Keyword: Field Theory

Search Result 3,179, Processing Time 0.026 seconds

Development and Assessment of Higher Order Zig-zag Theory for smart composite plates under mechanical, thermal, and electric loads (열-전기-기계 하중을 받는 스마트 복합재 평판의 고차 지그재그 유한요소의 개발 및 성능 평가)

  • 오진호;조맹효
    • Proceedings of the Korean Society For Composite Materials Conference
    • /
    • 2001.10a
    • /
    • pp.191-194
    • /
    • 2001
  • A partially coupled thermo-piezoelectric-mechanical triangular finite element model of composite laminates with surface bonded piezoelectric actuators, subjected to externally applied mechanical load, temperature change load, electric field load is developed. The governing differential equations are obtained by applying the principle of free energy and variational techniques. A higher order zigzag theory displacement field is employed to accurately capture the transverse shear and normal effects in laminated composite plates of arbitrary thickness. Nonconforming shape functions by Specht are employed in the transverse displacement variables. Numerical examples demonstrate the accuracy and efficiency of the proposed triangular plate element.

  • PDF

Thermomechanical deformation in porous generalized thermoelastic body with variable material properties

  • Kumar, Rajneesh;Devi, Savita
    • Structural Engineering and Mechanics
    • /
    • v.34 no.3
    • /
    • pp.285-300
    • /
    • 2010
  • The two-dimensional deformation of a homogeneous, isotropic thermoelastic half-space with voids with variable modulus of elasticity and thermal conductivity subjected to thermomechanical boundary conditions has been investigated. The formulation is applied to the coupled theory(CT) as well as generalized theories: Lord and Shulman theory with one relaxation time(LS), Green and Lindsay theory with two relaxation times(GL) Chandrasekharaiah and Tzou theory with dual phase lag(C-T) of thermoelasticity. The Laplace and Fourier transforms techniques are used to solve the problem. As an application, concentrated/uniformly distributed mechanical or thermal sources have been considered to illustrate the utility of the approach. The integral transforms have been inverted by using a numerical inversion technique to obtain the components of displacement, stress, changes in volume fraction field and temperature distribution in the physical domain. The effect of dependence of modulus of elasticity on the components of stress, changes in volume fraction field and temperature distribution are illustrated graphically for a specific model. Different special cases are also deduced.

Identification of Torque Characteristics in Capacitor Type Electric Motors and Reduction of Its Fluctuation Components (축전기형 전동기의 토크에 대한 특성분석 및 그 변동성분의 감소를 위한 연구)

  • 고홍석;신성수;김광준
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.18 no.4
    • /
    • pp.826-834
    • /
    • 1994
  • The purpose of this study is to identify torque characteristics in capacitor type electric motors and to illustrate the effects of several design parameters on the fluctuating components of the motor torque. To do this, two revolving field theory and stationary reference frame theory were applied to derive governing equations for the torque generated by motor. For simulation studies, parameters of the motor components were measured under the conditions of no loading and locking. Based on these, effects of several design variables on the torque characteristics were analyzed and compared with the actual measurements, which were estimated indirectly by measuring the stator voltage and current. Then, some illustrative improvements in design are suggested by taking Taguchi method.

Weight Function Theory for a Mode III Crack In a Rectilinear Anisotropic Material (가중함수이론을 이용한 선형이방성재료에서의 Mode III 균열해석)

  • An, Deuk-Man;Kwon, Sun-Hong
    • Journal of Ocean Engineering and Technology
    • /
    • v.23 no.1
    • /
    • pp.146-151
    • /
    • 2009
  • In this paper, a weight function theory for the calculation of the mode III stress intensity factor in a rectilinear anisotropic body is formulated. This formulation employs Lekhnitskii's formalism for two dimensional anisotropic materials. To illustrate the method used for the weight function theory, we calculated the mode III stress intensity factor in a single edge-notched configuration.

Recent Progresses in the Linguistic Modeling of Biological Sequences Based on Formal Language Theory

  • Park, Hyun-Seok;Galbadrakh, Bulgan;Kim, Young-Mi
    • Genomics & Informatics
    • /
    • v.9 no.1
    • /
    • pp.5-11
    • /
    • 2011
  • Treating genomes just as languages raises the possibility of producing concise generalizations about information in biological sequences. Grammars used in this way would constitute a model of underlying biological processes or structures, and that grammars may, in fact, serve as an appropriate tool for theory formation. The increasing number of biological sequences that have been yielded further highlights a growing need for developing grammatical systems in bioinformatics. The intent of this review is therefore to list some bibliographic references regarding the recent progresses in the field of grammatical modeling of biological sequences. This review will also contain some sections to briefly introduce basic knowledge about formal language theory, such as the Chomsky hierarchy, for non-experts in computational linguistics, and to provide some helpful pointers to start a deeper investigation into this field.

An Empirical Investigation of IT Adoption: Based on Movie Website (정보기술 수용에 관한 실증적 연구 : 영화관 웹사이트를 중심으로)

  • Kim, Jong-Weon;Jeong, Seok-Chan;Kim, Eun-Jung
    • The Journal of Information Systems
    • /
    • v.16 no.4
    • /
    • pp.157-176
    • /
    • 2007
  • Most of the Information Systems(IS) literature has focused on utilitarian or hedonic Information Technology(IT) to explain and predict IT adoption and use. This study investigates the relationships among individuals' beliefs and intention to use of movie website, which has both utilitarian and hedonic characteristics simultaneously. As a theoretical background, this study adopts Technology Acceptance Model(TAM) and Motivation Theory, in which the former is well-known as a theory of IT adoption and use in IS field, and the latter is famous for a theory of individual's behavior in organizational behavior field. With 153 responses, five hypotheses are tested by using structured equation model. The results show that perceived ease of use positively influences perceived usefulness and perceived enjoyment, and that all individuals' beliefs have a positive impact on intention to use of movie web-site. Based upon the study results, movie website's managers and professionals can plan and conduct their courses of action effectively for users' continuous visits on their operating website.

  • PDF

Research Trends Concerning Landscape Design in the Journal of the Korean Institute of Landscape Architecture (한국조경학회지 게재논문 조경설계 분야의 연구경향)

  • 김영대
    • Journal of the Korean Institute of Landscape Architecture
    • /
    • v.31 no.6
    • /
    • pp.107-119
    • /
    • 2004
  • special subjects, from basic data-building to applied design itself, and from how-why studies to theory building research. It seems that the research concerns are mainly the explanation of the processes of design projects rather than the application and expression of design theory and conceptual work itself. The articles do not show a clear trend or design concerns that would lead landscape architecture firms or its market. A few articles deal with aesthetical theory and with design criticism that could be one of landscape design's fundamental theories. It is not enough to regard the Journal of the Korean Institute of Landscape Architecture as the main stream of contemporary Korean landscape design trends. More research in the field of landscape design need to focus on pre-research work rather than on post-work reports. More research work in the field of landscape aesthetics is also required. The format of the journal needs to be reformed to include more design research papers that are of a free-presentation style in nature.

Analysis of Scattering of Electromagnetic Wave in Dielectric Periodic Media (유전체 격자구조에서 전자기파의 산란 해석)

  • Kim Min-Nyun;Chae Kyu-Su
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.5 no.5
    • /
    • pp.385-388
    • /
    • 2004
  • In this paper, we analyze the scattered electromagnetic wave by dielectric periodic media using the approximated thin phase screen theory. The phase screen approximated theory is that periodic media changes only the phase of the incident electromagnetic wave. Using this theory, we calculate the distribution of near field right after its passing periodic media. This theory can analyze a scattered field more simply and more quickly than existing theories.

  • PDF

Eringen's nonlocal elasticity theory for wave propagation analysis of magneto-electro-elastic nanotubes

  • Ebrahimi, Farzad;Dehghan, M.;Seyfi, Ali
    • Advances in nano research
    • /
    • v.7 no.1
    • /
    • pp.1-11
    • /
    • 2019
  • In this article, wave propagation characteristics in magneto-electro-elastic (MEE) nanotube considering shell model is studied in the framework nonlocal theory. To account for the small-scale effects, the Eringen's nonlocal elasticity theory of is applied. Nonlocal governing equations of MEE nanotube have been derived utilizing Hamilton's principle. The results of this investigation have been accredited by comparing them of previous studies. An analytical solution of governing equations is used to obtain phase velocities and wave frequencies. The influences of different parameters, such as different mode, nonlocal parameter, length parameter, geometry, magnetic field and electric field on wave propagation responses of MEE nanotube are expressed in detail.

NCS academic achievement and learning transfer ARCS motivation theory in ICT in the field of environmental education through interactive and immersive learning (NCS환경에서 ICT분야 교육에 ARCS 동기이론이 상호작용성과 학습몰입을 통해 학업성취도와 학습전이에 미치는 영향)

  • Park, Dongcheul;Kwon, Dosoon;Hwang, Changyu
    • Journal of Korea Society of Digital Industry and Information Management
    • /
    • v.11 no.3
    • /
    • pp.179-200
    • /
    • 2015
  • Recent national policies National Competency Standards(NCS) to develop teaching-oriented education in the field of industry and learning is taking place. Plan to take advantage of the Internet and multimedia classes, information and communication technology (ICT) for ways to leverage the integration appearing in various forms. The purpose of this study is causal influence on the ARCS motivation theory can determine the basic psychology of human motivation factors and the desires of a typical human nature theory dealing with the psychological needs of interactivity and immersion is learning achievement and learning transfer and to validate the demonstration. By applying information and communication technology sector in the development of learning in information and communication equipment training program modules from a field study conducted at the NCS with a clear empirical and empirical research through the synchronization to the learner and to explore the possibility of generalization.