• Title/Summary/Keyword: continuity theory

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Development of a 2D isoparametric finite element model based on the layerwise approach for the bending analysis of sandwich plates

  • Belarbia, Mohamed-Ouejdi;Tatib, Abdelouahab;Ounisc, Houdayfa;Benchabane, Adel
    • Structural Engineering and Mechanics
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    • v.57 no.3
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    • pp.473-506
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    • 2016
  • The aim of this work is the development of a 2D quadrilateral isoparametric finite element model, based on a layerwise approach, for the bending analysis of sandwich plates. The face sheets and the core are modeled individually using, respectively, the first order shear deformation theory and the third-order plate theory. The displacement continuity condition at the interfaces 'face sheets-core' is satisfied. The assumed natural strains method is introduced to avoid an eventual shear locking phenomenon. The developed element is a four-nodded isoparametric element with fifty two degrees-of-freedom (52 DOF). Each face sheet has only two rotational DOF per node and the core has nine DOF per node: six rotational degrees and three translation components which are common for the all sandwich layers. The performance of the proposed element model is assessed by six examples, considering symmetric/unsymmetric composite sandwich plates with different aspect ratios, loadings and boundary conditions. The numerical results obtained are compared with the analytical solutions and the numerical results obtained by other authors. The results indicate that the proposed element model is promising in terms of the accuracy and the convergence speed for both thin and thick plates.

3D nonlinear mixed finite-element analysis of RC beams and plates with and without FRP reinforcement

  • Hoque, M.;Rattanawangcharoen, N.;Shah, A.H.;Desai, Y.M.
    • Computers and Concrete
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    • v.4 no.2
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    • pp.135-156
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    • 2007
  • Three 3D nonlinear finite-element models are developed to study the behavior of concrete beams and plates with and without external reinforcement by fibre-reinforced plastic (FRP). All three models are formulated based upon the 3D theory of elasticity. The stress model is modified from the element developed by Ramtekkar, et al. (2002) to incorporate material nonlinearity in the formulation. Both transverse stress and displacement components are used as nodal degrees-of-freedom to ensure the continuity of both stress and displacement components between the elements. The displacement model uses only displacement components as nodal degrees-of-freedom. The transition model has both stress and displacement components as nodal degrees-of-freedom on one surface, and only displacement components as nodal degrees-of-freedom on the opposite surface. The transition model serves as a connector between the stress and the displacement models. The developed models are validated by comparing the results of the analyses with an existing experimental result. Parametric studies of the effects of the externally reinforced FRP on the load capacity of reinforced concrete (RC) beams and concrete plates are performed to demonstrate the practicality and the efficiency of the proposed models.

Analysis of the Sexual Health Education Curriculum of Nursing Schools in Korea using Posner's Theory (한국 간호교육기관의 성 건강 이론 교육과정 분석)

  • Kim, Hyun-Kyoung
    • Korean Journal of Adult Nursing
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    • v.26 no.2
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    • pp.223-233
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    • 2014
  • Purpose: This study was aimed to analyze the sexual health curriculum for the nursing baccalaureate and associate's degrees in Korea. The curriculum proper based on Posner's theory presented the analysis of purpose, content, organization, and underlying assumption. Methods: This study was conducted with sexual health education guidelines, nursing practice standards, 181 curriculums, and teaching materials. Data were collected through literature, online homepage from 181 nursing school, and textbooks from July to September, 2013. Data were analyzed using percentage and mean with SPSS 12.0. Results: The purposes were mostly included in the low grade cognitive learning domain. The contents included 20 key elements among 22, so the scope was not inclusive. There was an unbalance between content's depth and scope, because total mean credit of sexual health nursing education was only 19.81 hours. The spiral structure of organization showed continuity, sequence, and integration with international standards. The interdisciplinary integration and transcultural value were advantages of the curriculum. Conclusion: This study provided a view on understanding sexual health nursing curriculum and implication for advanced education. The proclaiming of the standard and concept mapping of sexual health curriculum may contribute to the curriculum development for the advanced nursing.

Time-dependent creep analysis and life assessment of 304 L austenitic stainless steel thick pressurized truncated conical shells

  • Kashkoli, Mosayeb Davoudi;Nejad, Mohammad Zamani
    • Steel and Composite Structures
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    • v.28 no.3
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    • pp.349-362
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    • 2018
  • This paper presents a semi-analytical solution for the creep analysis and life assessment of 304L austenitic stainless steel thick truncated conical shells using multilayered method based on the first order shear deformation theory (FSDT). The cone is subjected to the non-uniform internal pressure and temperature gradient. Damages are obtained in thick truncated conical shell using Robinson's linear life fraction damage rule, and time to rupture and remaining life assessment is determined by Larson-Miller Parameter (LMP). The creep response of the material is described by Norton's law. In the multilayer method, the truncated cone is divided into n homogeneous disks, and n sets of differential equations with constant coefficients. This set of equations is solved analytically by applying boundary and continuity conditions between the layers. The results obtained analytically have been compared with the numerical results of the finite element method. The results show that the multilayered method based on FSDT has an acceptable amount of accuracy when one wants to obtain radial displacement, radial, circumferential and shear stresses. It is shown that non-uniform pressure has significant influences on the creep damages and remaining life of the truncated cone.

A Social Cultural Approach to Illegal Digital Contents Sharing (디지털콘텐츠 불법 파일공유에 관한 사회문화적 접근)

  • Park, Kyung Ja
    • Knowledge Management Research
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    • v.17 no.1
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    • pp.113-133
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    • 2016
  • Why illegal digital contents sharing happens? This study pays attention to the fact that file sharing is an exchanging behavior between people and it is expanding despite of an illegal behavior and proposes that it is necessary for the phenomenon to be understood from social cultural point of view beyond a personal dimension. Based on the social exchange theory, this study demonstrates effects of file sharing attitudes and continuity, regarding 'group norm', 'popular demand', 'reciprocity' and 'social solidarity' as main factors. The main findings of this study are as followed;- First, it is shown that a tacit agreement of a group on file sharing is a determinant of positive attitude to file sharing and the intent of continual file sharing. Second, it is not found that the social relationship factors that are regarded as potential influential factors on file sharing attitude have effects on file sharing behavior, except for 'group norm'. Unlike previous studies, the results may come from the fact that this study deals with an illegal behavior. The third finding indicates a structural relationship between social relationship factors. When members of a group have more amicable attitude to file sharing including silence or a tacit agreement on file sharing, more people ask illegal sharing of files that they need. Such public demand creates expectation of reciprocity. As reciprocity maintains, social connectedness is strengthened. Then, strong social connectedness escalates the intent to maintain file sharing. It is important to notice that this study promotes understanding of how digital contents sharing happens by structuring and demonstrating influential relationship between characteristic factors of the social relationship.

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Free Vibration of Composite Cylindrical Shells with a Longitudinal, Interior Rectangular Plate (내부에 사각판이 결합된 복합재료 원통쉘의 자유진동)

  • 이영신;최명환
    • Composites Research
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    • v.12 no.5
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    • pp.65-79
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    • 1999
  • This paper descrives the method to analyzed the free vibratioin of supported composite cylindrical shells with a longitudinal, interior rectangular plate. To obtain the free vibration characteristics before the combination of two structures, the energy principle based on the classical plate theory and Love's thin shell theory is adopted. The frequency equation of the combined system is formulated using the receptance method. When the line load and moment applied along the joint are assumed as the the Dirac delta and sinusolidal function, the continuity conditions at the joint of the plate and shell are proven to be satisfied. The effects on the combined shell frequencies of the length-no-radius ratios and radius-to-thickness ratios of the shell, fiber orientation angles and orthotropic modulus ratios of the composite are also examined.

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Determinant of Market Orientation on SME Performance: RBV and SCP Perspective

  • NURHILALIA, NURHILALIA;RAHMAN Kadir, Abdul;MAHLIA, Muis;JUSNI, JUSNI;ADITYA, Halim Perdana Kusuma Putra
    • Journal of Distribution Science
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    • v.17 no.9
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    • pp.35-45
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    • 2019
  • Purpose - This study analyzes the relationship between inter-function coordination variables, competitor, customer and innovation orientation that has been developed by Narver & Slater (1990), also known as Market Orientation Strategy on SME Sutera's marketing performance, through direct and indirect effect relationships. Research design, data, and methodology - This study uses a sample of 168 respondents who are silk SME entrepreneurs in eleven Silk Craftsman sub-districts in Wajo Regency - South Sulawesi Province, Indonesia. Data collection using a questionnaire with a period between January - June 2019. Data analysis use PLS. The stages of testing the results of analysis go through several stages: the first stage, analysis of variable descriptions, the goodness of fit model (AVE, CR, Cronbach Alpha, R2) and hypothesis test. Results and Findings - From the fifteen hypothesis by direct and indirect effect state six hypothesis are rejected and eleven hypothesis are accepted. Overall, the concepts of Resource Based View theory (RBV) and Structure-Conduct- Performance theory (SCP) also provide a strategic picture for businessmen related to product innovation and service innovation and the urgency of regeneration in order to maintain the continuity of superior products in the future.

A study on muscular system of Foot yangmyung meridian-muscle (족양명경근(足陽明經筋)의 근육학적(筋肉學的) 고찰(考察))

  • Song, Jong-Keun;Yim, Yun-Kyoung
    • Korean Journal of Acupuncture
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    • v.23 no.2
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    • pp.39-46
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    • 2006
  • Objective & Methods: This study is performed to understand the interrelation between 'Foot yangmyung meridian-muscle' and 'muscular system'. We studied the literatures on Meridian-muscle theory, anatomical muscular system, myofascial pain syndrome and the theory of anatomy trains. Results & Conclusion: 1. It is considered that Foot yangmyung meridian-muscle includes extensor digitorum longus m., tibialis anterior m., quadriceps femoris m., rectus abdominis m., pectoralis major m., sternocleidomastoid m., platysma m., orbicular oris m., zygomaticus major m., zygomaticus minor m., masseter m., Gluteus medius m., and Obliquus externus abdominis m. 2. The symptoms of Foot yangmyung meridian-muscle are similar to the myofascial pain syndrome with referred pain of extensor digitorum longus m., tibialis anterior m., quadriceps femoris m., rectus abdominis m., obliquus abdominis m., masseter m. 3. Superficial frontal line in anatomy trains is similar to the pathway of Foot yangmyung meridian-muscle, and more studies are needed in anatomy and physiology to support the continuity of muscular system of Foot yangmyung meridian-muscle in aspect of anatomy trains.

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Analytical and multicoupled methods for optimal steady-state thermoelectric solutions

  • Moreno-Navarro, Pablo;Perez-Aparicio, Jose L.;Gomez-Hernandez, J.J.
    • Coupled systems mechanics
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    • v.11 no.2
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    • pp.151-166
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    • 2022
  • Peltier cells have low efficiency, but they are becoming attractive alternatives for affordable and environmentally clean cooling. In this line, the current article develops closed-form and semianalytical solutions to improve the temperature distribution of Bi2Te3 thermoelements. From the distribution, the main objective of the current work-the optimal electric intensity to maximize cooling-is inferred. The general one-dimensional differential coupled equation is integrated for linear and quadratic geometry of thermoelements, under temperature constant properties. For a general shape, a piece-wise solution based on heat flux continuity among virtual layers gives accurate analytical solutions. For variable properties, another piece-wise solution is developed but solved iteratively. Taking advantage of the formulae, the optimal intensity is directly derived with a minimal computational cost; its value will be of utility for more advanced designs. Finally, a parametric study including straight, two linear, barrel, hourglass and vase geometries is presented, drawing conclusions on how the shape of the thermoelement affects the coupled phenomena. A specially developed coupled and non-linear finite element research code is run taking into account all the materials of the cell and using symmetries and repetitions. These accurate results are used to validate the analytical ones.

An efficient C1 beam element via multi-scale material adaptable shape function

  • El-Ashmawy, A.M.;Xu, Yuanming
    • Advances in nano research
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    • v.13 no.4
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    • pp.351-368
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    • 2022
  • Recently, promising structural technologies like multi-function, ultra-load bearing capacity and tailored structures have been put up for discussions. Finite Element (FE) modelling is probably the best-known option capable of treating these superior properties and multi-domain behavior structures. However, advanced materials such as Functionally Graded Material (FGM) and nanocomposites suffer from problems resulting from variable material properties, reinforcement aggregation and mesh generation. Motivated by these factors, this research proposes a unified shape function for FGM, nanocomposites, graded nanocomposites, in addition to traditional isotropic and orthotropic structural materials. It depends not only on element length but also on the beam's material properties and geometric characteristics. The systematic mathematical theory and FE formulations are based on the Timoshenko beam theory for beam structure. Furthermore, the introduced element achieves C1 degree of continuity. The model is proved to be convergent and free-off shear locking. Moreover, numerical results for static and free vibration analysis support the model accuracy and capabilities by validation with different references. The proposed technique overcomes the issue of continuous properties modelling of these promising materials without discarding older ones. Therefore, introduced benchmark improvements on the FE old concept could be extended to help the development of new software features to confront the rapid progress of structural materials.