• Geomechanics and Engineering
• /
• v.18 no.2
• /
• pp.161-178
• /
• 2019

In this research, a simple quasi 3D hyperbolic shear deformation model is employed for bending and dynamic behavior of functionally graded (FG) plates resting on visco-Pasternak foundations. The important feature of this theory is that, it includes the thickness stretching effect with considering only 4 unknowns, which less than what is used in the First Order Shear Deformation (FSDT) theory. The visco­Pasternak's foundation is taken into account by adding the influence of damping to the usual foundation model which characterized by the linear Winkler's modulus and Pasternak's foundation modulus. The equations of motion for thick FG plates are obtained in the Hamilton principle. Analytical solutions for the bending and dynamic analysis are determined for simply supported plates resting on visco-Pasternak foundations. Some numerical results are presented to indicate the effects of material index, elastic foundation type, and damping coefficient of the foundation, on the bending and dynamic behavior of rectangular FG plates.

• Structural Engineering and Mechanics
• /
• v.65 no.5
• /
• pp.621-631
• /
• 2018

In this paper, an exact analytical solution is developed for the analysis of the post-buckling non-linear response of simply supported deformable symmetric composite beams. For this, a new theory of higher order shear deformation is used for the analysis of composite beams in post-buckling. Unlike any other shear deformation beam theories, the number of functions unknown in the present theory is only two as the Euler-Bernoulli beam theory, while three unknowns are needed in the case of the other beam theories. The theory presents a parabolic distribution of transverse shear stresses, which satisfies the nullity conditions on both sides of the beam without a shear correction factor. The shear effect has a significant contribution to buckling and post-buckling behaviour. The results of this analysis show that classical and first-order theories underestimate the amplitude of the buckling whereas all the theories considered in this study give results very close to the static response of post-buckling. The numerical results obtained with the novel theory are not only much more accurate than those obtained using the Euler-Bernoulli theory but are almost comparable to those obtained using higher order theories, Accuracy and effectiveness of the current theory.

• The Journal of the Korea Contents Association
• /
• v.21 no.10
• /
• pp.508-519
• /
• 2021

The purpose of this study was to develop an ICT education program using films to understand and expand of the Interpersonal Caring Theory (ICT). The study was conducted from February 2020 to October 2020. The films were selected by analyzing 10 elements of ICT and the program was developed according to Kolb's Experience Learning Model. 11 experienced nurses participated in the pilot operation of the program and evaluated the validity of the films as experts. The films selected for the ICT education program included The Blind Side (Noticing), Babette's Feast (Participation), Good Will Hunting (Sharing), The King's Speech (Active-listening), The Cure (Companioning), Mr. Holland's Opus (Complimenting), Patch Adams (Comforting), The Shawshank Redemption (Hoping), Mission (Forgiving), The Throne (Accepting). The program consisted of a total of 12 sessions, and each session included discussion questions for the steps of the Experimental Learning Model. After the program was piloted, it was found that the selected films were considered appropriate (I-CVI=0.98) as a result of evaluating the feasibility of films selection according to ICT elements. The developed ICT education program using films can be used to enhance caring competencies of nurses and nursing college students.

• Steel and Composite Structures
• /
• v.18 no.3
• /
• pp.793-809
• /
• 2015

In this scientific work, constructing of a novel shear deformation beam model including the stretching effect is of concern for flexural and free vibration responses of functionally graded beams. The particularity of this model is that, in addition to considering the transverse shear deformation and the stretching effect, the zero transverse shear stress condition on the beam surface is assured without introducing the shear correction parameter. By employing the Hamilton's principle together with the concept of the neutral axe's position for such beams, the equations of motion are obtained. Some examples are performed to demonstrate the effects of changing gradients, thickness stretching, and thickness to length ratios on the bending and vibration of functionally graded beams.

• Journal of Korean Medical classics
• /
• v.7
• /
• pp.113-160
• /
• 1994

The Sa-Ahm monk, who was believed to have existed in the middle of Cho-Seon Dynasty in Korea, have created an original Sa-Ahm's acupuncture method and written down, "Book of Sa-Ahm's 5 Element Acupuncture Method" using not only laws of creation and suppression in 5 element theory but also its main and other connected meridians according to the daignosis of visceras and bowels. Also the written time and background of its theory have not been known, and after obtaining Ji-San's book on Sa-Ahm's acupuncture method, I studied on them. The results are as follows : 1) The treatment chapter of Book of Sa-Ahm's 5 Element Acupuncture Method was written down by Sa-Ahm himself, and the chapter for Medical Experience was found to be written down by Ji-San. 2) It seemed that Sa-Ahm adopted the main ideas of "Eui Hak Jeong Jon(醫學正傳)" for the section of physiology, pathology and classification of disease symptoms the contents of which covered 40 of 43 parts, and the ideas of "Dong Eui Bo Gam(東醫寶鑑)" for YunGi treatise(運氣篇), and SangHan part(傷寒門) in classification of diease symptoms was intensified by the ideas of "Eui Hak Ip Moon(醫學入門)", and the contents of apoplexy, diseases characterized by acute diarrhea and vomiting, beriberi, diseases of oral cavity were intensified by the ideas of "Chim Ku Kyeong Hearn Bang(鍼灸經驗方)". 3) The written date of the Book of Sa-Ahm's 5 Element Acupuncture Method has been established as 1644 AD(22nd year of In Jo king of Cho-Seon Dynasty) after studying preface, contents and acknowledgement of Heo Im's "Chim Ku Kyeong Hearn Bang(鍼灸經驗方)". 4) The philosophic background of "Sa-Am Acupuncture Method(舍巖鍼法)" seems to be derived from the theories of "I Ching(周易)" and Yin Yang 5 Element Theory(陰陽五行學說), and to be influenced by such medical scholars as Tan Ke(丹溪), Woo Bak(虞搏), and Heo Im(許任).

• Steel and Composite Structures
• /
• v.26 no.2
• /
• pp.125-137
• /
• 2018

In this work, the bending and free vibration analysis of multilayered plates and shells is presented by utilizing a new higher order shear deformation theory (HSDT). The proposed involves only four unknowns, which is even less than the first shear deformation theory (FSDT) and without requiring the shear correction coefficient. Unlike the conventional HSDTs, the present one presents a novel displacement field which incorporates undetermined integral variables. The equations of motion are derived by using the Hamilton's principle. These equations are then solved via Navier-type, closed form solutions. Bending and vibration results are found for cylindrical and spherical shells and plates for simply supported boundary conditions. Bending and vibration problems are treated as individual cases. Panels are subjected to sinusoidal, distributed and point loads. Results are presented for thick to thin as well as shallow and deep shells. The computed results are compared with the exact 3D elasticity theory and with several other conventional HSDTs. The proposed HSDT is found to be precise compared to other several existing ones for investigating the static and dynamic response of isotropic and multilayered composite shell and plate structures.

• Structural Engineering and Mechanics
• /
• v.57 no.5
• /
• pp.837-859
• /
• 2016

An efficient shear deformation theory is developed for wave propagation analysis of an infinite functionally graded plate in the presence of thermal environments. By dividing the transverse displacement into bending and shear parts, the number of unknowns and governing equations of the present theory is reduced, and hence, makes it simple to use. The thermal effects and temperature-dependent material properties are both taken into account. The temperature field is assumed to be a uniform distribution over the plate surface and varied in the thickness direction only. Material properties are assumed to be temperature-dependent, and graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. The governing equations of the wave propagation in the functionally graded plate are derived by employing the Hamilton's principle and the physical neutral surface concept. There is no stretching.bending coupling effect in the neutral surface-based formulation, and consequently, the governing equations and boundary conditions of functionally graded plates based on neutral surface have the simple forms as those of isotropic plates. The analytic dispersion relation of the functionally graded plate is obtained by solving an eigenvalue problem. The effects of the volume fraction distributions and temperature on wave propagation of functionally graded plate are discussed in detail. It can be concluded that the present theory is not only accurate but also simple in predicting the wave propagation characteristics in the functionally graded plate. The results carried out can be used in the ultrasonic inspection techniques and structural health monitoring.

• Structural Engineering and Mechanics
• /
• v.62 no.6
• /
• pp.695-702
• /
• 2017

In this work, a nonlocal zeroth-order shear deformation theory is developed for the nonlinear postbuckling behavior of nanoscale beams. The beauty of this formulation is that, in addition to including the nonlocal effect according to the nonlocal elasticity theory of Eringen, the shear deformation effect is considered in the axial displacement within the use of shear forces instead of rotational displacement like in existing shear deformation theories. The principle of virtual work together of the nonlocal differential constitutive relations of Eringen, are considered to obtain the equations of equilibrium. Closed-form solutions for the critical buckling load and the amplitude of the static nonlinear response in the postbuckling state for simply supported and clamped clamped nanoscale beams are determined.

• Smart Structures and Systems
• /
• v.26 no.2
• /
• pp.213-226
• /
• 2020

In this manuscript, static and dynamic behaviors of geometrically imperfect carbon nanotubes (CNTs) subject to different types of end conditions are investigated. The Doublet Mechanics (DM) theory, which is length scale dependent theory, is used in the analysis. The Euler-Bernoulli kinematic and nonlinear mid-plane stretching effect are considered through analysis. The governing equation of imperfect CNTs is a sixth order nonlinear integro-partial-differential equation. The buckling problem is discretized via the differential-integral-quadrature method (DIQM) and then it is solved using Newton's method. The equation of linear vibration problem is discretized using DIQM and then solved as a linear eigenvalue problem to get natural frequencies and corresponding mode shapes. The DIQM results are compared with analytical ones available in the literature and excellent agreement is obtained. The numerical results are depicted to illustrate the influence of length scale parameter, imperfection amplitude and shear foundation constant on critical buckling load, post-buckling configuration and linear vibration behavior. The current model is effective in designing of NEMS, nano-sensor and nano-actuator manufactured by CNTs.

• Wind and Structures
• /
• v.27 no.5
• /
• pp.311-324
• /
• 2018

This work examines vibration and bending response of carbon nanotube-reinforced composite plates resting on the Pasternak elastic foundation. Four types of distributions of uni-axially aligned single-walled carbon nanotubes are considered to reinforce the plates. Analytical solutions determined from mathematical formulation based on hyperbolic shear deformation plate theory are presented in this study. An accuracy of the proposed theory is validated numerically by comparing the obtained results with some available ones in the literature. Various considerable parameters of carbon nanotube volume fraction, spring constant factors, plate thickness and aspect ratios, etc. are considered in the present investigation. According to the numerical examples, it is revealed that the vertical displacement of the plates is found to diminish as the increase of foundation parameters; while, the natural frequency increase as the increment of the parameters for every type of plate.