• Title/Summary/Keyword: higher-order theories

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A Survey on Students' Perception of Communication Skills in Class of Theories of Korean Medical Famous Physicians (각가의론 수업에서 학습한 의사소통기술에 대한 학생 인식 조사)

  • Jo, Hak-Jun;Jo, Na-Young;Park, Jeong-Su
    • Journal of Society of Preventive Korean Medicine
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    • v.25 no.2
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    • pp.13-31
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    • 2021
  • Objectives : The objectives of this study are to provide the education of communication skills in the class of theories of Korean medical famous physicians and to survey students' perception of the effect. Methods : The class of theories of Korean medical famous physicians was newly designed and was given to students. The results from the questionnaire survey with second year students at department of Korean medicine were applied to the evaluation of study issues. The scale used for this study was the modified version of 'Beyer-Fetzer's Essential Elements of Communication Skills Assessment Sheet', which was developed by researchers in line with the education of Korean medicine. Results : In six (except for 'opening a conversation') out of seven categories, post-test results were more improved than pretest results. In the category of communication skills (a total of 25 questions), post-test results were higher than pretest results in all items. Among them, 13 items were statistically significant. With regard to the question as to how important the class of communication skills is to raise their professionalism as Korean medicine doctor, post-test result was higher than pretest result. Regarding an appropriate education point of time, there were various points in the entire period of curriculum. The appropriateness of teaching-learning method was positively evaluated. In terms of the content helpful for learning, learner-oriented activities was preferred over teacher-oriented lecturing. Conclusions : The communication skills learned in the class of theories of Korean medical famous physicians were effective. Communications skills should be taught constantly in the entire curriculum in order to raise students' professionalism as Korean medicine doctor. In terms of education method, it is desirable to design a class based on students' various activities, rather than lecturing.

Nurse Characteristics related to Level of Use of Essential Oriental Nursing Terms in Oriental Medicine Hospitals (한방병원 간호사들의 한방간호 필수용어 활용도와 관련된 특성)

  • Hwang, Jee-In;Kim, Won-Ock;Wang, Myoung-Ja
    • Journal of Korean Academy of Nursing Administration
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    • v.17 no.2
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    • pp.209-215
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    • 2011
  • Purpose: This study was done to examine the level of use of essential oriental nursing terms and related characteristics among nurses in oriental medicine (OM) hospitals. Method: A cross-sectional survey design with convenience sampling was employed. Questionnaires were used to collect data from 315 nurses in seven university-affiliated OM hospitals. The questionnaire included 174 oriental nursing terms about actions, tests, drugs, and theories. Multiple regression analysis was performed to determine factors associated with the level of use. Results: The response rate was 98.1% (n=309). Overall mean score for use of essential oriental nursing terms was 2.7(${\pm}\;0.7$) on a five-point Likert scale. Significant factors associated with the level of use were workplace and knowledge of oriental nursing theory terms. Nurses who worked in nursing care wards and those who had a higher level of knowledge of oriental nursing theories had a higher level of use. Conclusions: These findings indicate that level of use of essential oriental nursing terms were below average. Educational programs to enhance knowledge of oriental nursing theories need to be implemented for nurses in OM hospitals, considering their workplace, in order to facilitate nursing data sharing and communication among healthcare providers.

Buckling and stability analysis of sandwich beams subjected to varying axial loads

  • Eltaher, Mohamed A.;Mohamed, Salwa A
    • Steel and Composite Structures
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    • v.34 no.2
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    • pp.241-260
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    • 2020
  • This article presented a comprehensive model to study static buckling stability and associated mode-shapes of higher shear deformation theories of sandwich laminated composite beam under the compression of varying axial load function. Four higher order shear deformation beam theories are considered in formulation and analysis. So, the model can consider the influence of both thick and thin beams without needing to shear correction factor. The compression force can be described through axial direction by uniform constant, linear and parabolic distribution functions. The Hamilton's principle is exploited to derive equilibrium governing equations of unified sandwich laminated beams. The governing equilibrium differential equations are transformed to algebraic system of equations by using numerical differential quadrature method (DQM). The system of equations is solved as an eigenvalue problem to get critical buckling loads and their corresponding mode-shapes. The stability of DQM in determining of buckling loads of sandwich structure is performed. The validation studies are achieved and the obtained results are matched with those. Parametric studies are presented to figure out effects of in-plane load type, sandwich thickness, fiber orientation and boundary conditions on buckling loads and mode-shapes. The present model is important in designing process of aircraft, naval structural components, and naval structural when non-uniform in-plane compressive loading is dominated.

Static analysis of the FGM plate with porosities

  • Benferhat, R.;Hassaine Daouadji, T.;Hadji, L.;Said Mansour, M.
    • Steel and Composite Structures
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    • v.21 no.1
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    • pp.123-136
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    • 2016
  • This work focuses on the behavior of the static analysis of functionally graded plates materials (FGMs) with porosities that may possibly occur inside the functionally graded materials (FGMs) during their fabrication. For this purpose a new refined plate theory is used in this work, it contains only four unknowns, unlike five unknowns for other theories. This new model meets the nullity of the transverse shear stress at the upper and lower surfaces of the plate. The parabolic distribution of transverse shear stresses along the thickness of the plate is taken into account in this analysis; the material properties of the FGM plate vary a power law distribution in terms of volume fraction of the constituents. The rule of mixture is modified to describe and approximate material properties of the FG plates with porosity phases. The validity of this theory is studied by comparing some of the present results with other higher-order theories reported in the literature, the influence of material parameter, the volume fraction of porosity and the thickness ratio on the behavior mechanical P-FGM plate are represented by numerical examples.

A new refined nonlocal beam theory accounting for effect of thickness stretching in nanoscale beams

  • Kheroubi, Boumediene;Benzair, Abdelnour;Tounsi, Abdelouahed;Semmah, Abdelwahed
    • Advances in nano research
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    • v.4 no.4
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    • pp.251-264
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    • 2016
  • In this paper, a simple and refined nonlocal hyperbolic higher-order beam theory is proposed for bending and vibration response of nanoscale beams. The present formulation incorporates the nonlocal scale parameter which can capture the small scale effect, and it considers both shear deformation and thickness stretching effects by a hyperbolic variation of all displacements across the thickness without employing shear correction factor. The highlight of this formulation is that, in addition to modeling the displacement field with only two unknowns, the thickness stretching effect (${\varepsilon}_z{\neq}0$) is also included in the present model. By utilizing the Hamilton's principle and the nonlocal differential constitutive relations of Eringen, the equations of motion of the nanoscale beam are reformulated. Verification studies demonstrate that the developed theory is not only more accurate than the refined nonlocal beam theory, but also comparable with the higher-order shear deformation theories which contain more number of unknowns. The theoretical formulation proposed herein may serve as a reference for nonlocal theories as applied to the static and dynamic responses of complex-nanobeam-system such as complex carbon nanotube system.

A new simple shear and normal deformations theory for functionally graded beams

  • Bourada, Mohamed;Kaci, Abdelhakim;Houari, Mohammed Sid Ahmed;Tounsi, Abdelouahed
    • Steel and Composite Structures
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    • v.18 no.2
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    • pp.409-423
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    • 2015
  • In the present work, a simple and refined trigonometric higher-order beam theory is developed for bending and vibration of functionally graded beams. The beauty of this theory is that, in addition to modeling the displacement field with only 3 unknowns as in Timoshenko beam theory, the thickness stretching effect (${\varepsilon}_Z{\neq}0$) is also included in the present theory. Thus, the present refined beam theory has fewer number of unknowns and equations of motion than the other shear and normal deformations theories, and it considers also the transverse shear deformation effects without requiring shear correction factors. The neutral surface position for such beams in which the material properties vary in the thickness direction is determined. Based on the present refined trigonometric higher-order beam theory and the neutral surface concept, the equations of motion are derived from Hamilton's principle. Numerical results of the present theory are compared with other theories to show the effect of the inclusion of transverse normal strain on the deflections and stresses.

Flexural and free vibration responses of thick isotropic bridge deck using a novel two variable refined plate theory

  • Djidar, Fatima Zohra;Hebali, Habib;Amara, Khaled;Tounsi, Abdelouahed;Bendaho, Boudjema;Ghazwani, M.H.;Hussain, Muzamal
    • Structural Engineering and Mechanics
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    • v.82 no.6
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    • pp.725-734
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    • 2022
  • This work presents a simple exponential shear deformation theory for the flexural and free vibration responses of thick bridge deck. Contrary to the existing higher order shear deformation theories (HSDT) and the first shear deformation theory (FSDT), the proposed model uses a new displacement field which incorporates undetermined integral terms and involves only two variables. Governing equations and boundary conditions of the theory are derived by the principle of virtual work. The simply supported thick isotropic square and rectangular plates are considered for the detailed numerical studies. Results of displacements, stresses and frequencies are compared with those of other refined theories and exact theory to show the efficiency of the proposed theory. Good agreement is achieved of the present results with those of higher order shear deformation theory (HSDT) and elasticity theory. Moreover, results demonstrate that the developed two variable refined plate theory is simple for solving the flexural and free vibration responses of thick bridge deck and can achieve the same accuracy of the existing HSDTs which have more number of variables.

Buckling and vibration of porous sandwich microactuator-microsensor with three-phase carbon nanotubes/fiber/polymer piezoelectric polymeric nanocomposite face sheets

  • Arani, Ali Ghorbanpour;Navi, Borhan Rousta;Mohammadimehr, Mehdi
    • Steel and Composite Structures
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    • v.41 no.6
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    • pp.805-820
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    • 2021
  • In this research, the buckling and free vibration of three-phase carbon nanotubes/ fiber/ polymer piezoelectric nanocomposite face sheet sandwich microbeam with microsensor and micro-actuator surrounded in elastic foundation based on modified couple stress theory (MCST) is investigated. Three types of porous materials are considered for sandwich core. Higher order (Reddy) and sinusoidal shear deformation beam theories are employed for the displacement fields. Sinusoidal surface stress effects are extracted for sinusoidal shear deformation beam theory. The equations of motion are derived by Hamilton's principle and then the natural frequency and critical buckling load are obtained by Navier's type solution. The determined results are in good agreement with other literatures. The detailed numerical investigation for various parameters is performed for this microsensor-microactuator. The results reveal that the microsensor-microactuator enhanced by increasing of Skempton coefficient, carbon nanotubes diameter length to thickness ratio, small scale factor, elastic foundation, surface stress constants and reduction in porous coefficient, micro-actuator voltage and CNT weight fraction. The valuable results can be expedient for micro-electro-mechanical (MEMS) and nano-electro-mechanical (NEMS) systems.

The effect of transverse shear deformation on the post-buckling behavior of functionally graded beams

  • Meksi, Ali;Youzera, Hadj;Sadoun, Mohamed;Abbache, Ali;Meftah, Sid Ahmed;Tounsi, Abdelouahed;Hussain, Muzamal
    • Steel and Composite Structures
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    • v.44 no.1
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    • pp.81-89
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    • 2022
  • The purposes of the present work it to study the effect of shear deformation on the static post-buckling response of simply supported functionally graded (FGM) axisymmetric beams based on classical, first-order, and higher-order shear deformation theories. The behavior of postbuckling is introduced based on geometric nonlinearity. The material properties of functionally graded materials (FGM) are assumed to be graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. The equations of motion and the boundary conditions derived using Hamilton's principle. This article compares and addresses the efficiency, the applicability, and the limits of classical models, higher order models (CLT, FSDT, and HSDT) for the static post-buckling response of an asymmetrically simply supported FGM beam. The amplitude of the static post-buckling obtained a solving the nonlinear governing equations. The results showing the variation of the maximum post-buckling amplitude with the applied axial load presented, for different theory and different parameters of material and geometry. In conclusion: The shear effect found to have a significant contribution to the post-buckling behaviors of axisymmetric beams. As well as the classical beam theory CBT, underestimate the shear effect compared to higher order shear deformation theories HSDT.

Wave dispersion properties in imperfect sigmoid plates using various HSDTs

  • Batou, Belaid;Nebab, Mokhtar;Bennai, Riadh;Atmane, Hassen Ait;Tounsi, Abdeldjebbar;Bouremana, Mohammed
    • Steel and Composite Structures
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    • v.33 no.5
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    • pp.699-716
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    • 2019
  • In this paper, wave propagations in sigmoid functionally graded (S-FG) plates are studied using new Higher Shear Deformation Theory (HSDT) based on two-dimensional (2D) elasticity theory. The current higher order theory has only four unknowns, which mean that few numbers of unknowns, compared with first shear deformations and others higher shear deformations theories and without needing shear corrector. The material properties of sigmoid functionally graded are assumed to vary through thickness according sigmoid model. The S-FG plates are supposed to be imperfect, which means that they have a porous distribution (even and uneven) through the thickness of these plates. The governing equations of S-FG plates are derived employed Hamilton's principle. Using technique of Navier, differential equations of S-FG in terms displacements are solved. Extensive results are presented to check the efficient of present methods to predict wave dispersion and velocity wave in S-FG plates.