• Structural Engineering and Mechanics
• /
• 제73권1호
• /
• pp.97-108
• /
• 2020

This study presents a 4 node, 11 DOF/node plate element based on higher order shear deformation theory for lamina composite plates. The theory accounts for parabolic distribution of the transverse shear strain through the thickness of the plate. Differential field equations of composite plates are obtained from energy methods using virtual work principle. Differential field equations of composite plates are obtained from energy methods using virtual work principle. These equations were transformed into the operator form and then transformed into functions with geometric and dynamic boundary conditions with the help of the Gâteaux differential method, after determining that they provide the potential condition. Boundary conditions were determined by performing variational operations. By using the mixed finite element method, plate element named HOPLT44 was developed. After coding in FORTRAN computer program, finite element matrices were transformed into system matrices and various analyzes were performed. The current results are verified with those results obtained in the previous work and the new results are presented in tables and graphs.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2003년도 봄 학술발표회 논문집
• /
• pp.875-883
• /
• 2003

Slurry clay has much higher water content than liquid limit of clay and even if small loads apply, it suffers a great settlement. Accordingly it is very difficult to perform a general consolidation test about slurry clay because of high water content. In this study consolidation tests have been performed successfully using Rowe Cell Tester about 1 remolding clay and 3 slurry clays with a water content of 100%, 133% and 150%. From the test results compression index characteristics, secondary compression index characteristics and consolidation coefficient characteristics have been investigated about slurry clay and remolding clay. Also two kinds of theory, by Terzaghi theory and by Mikasa theory, has been used to calculate consolidation coefficients. Compared to the calculation results, they had a similar value of consolidation coefficient. However if Mikasa theory is applied in the field design, the period which reach to the required consolidation degree will be much reduced compared to the period by Terzaghi theory because the time coefficient T$\_$v/ by Mikasa theory is far smaller than T$\_$v/ by Terzaghi theory.

• Steel and Composite Structures
• /
• 제26권4호
• /
• pp.421-437
• /
• 2018

Free vibration analysis of a three-layered microbeam including an elastic micro-core and two piezo-magnetic face-sheets resting on Pasternak's foundation are studied in this paper. Strain gradient theory is used for size-dependent modeling of microbeam. In addition, three-unknown shear and normal deformations theory is employed for description of displacement field. Hamilton's principle is used for derivation of the governing equations of motion in electro-magneto-mechanical loads. Three micro-length-scale parameters based on strain gradient theory are employed for prediction of vibrational characteristics of structure in micro-scale. The results show that increase of three micro-length-scale parameters leads to significant increase of three natural frequencies especially for increase of second micro-length-scale parameter. This result is according to this fact that stiffness of a micro-scale structure is increased with increase of micro-length-scale parameters.

• Steel and Composite Structures
• /
• 제25권4호
• /
• pp.389-401
• /
• 2017

In this work, a new higher shear deformation theory (HSDT) is developed for the free vibration and buckling of functionally graded (FG) sandwich plates. The proposed theory presents a new displacement field by using undetermined integral terms. Only four unknowns are employed in this theory, which is less than the classical first shear deformation theory (FSDT) and others HSDTs. Equations of motion are obtained via Hamilton's principle. The analytical solutions of FG sandwich plates are determined by employing the Navier method. A good agreement between the computed results and the available solutions of existing HSDTs is found to prove the accuracy of the developed theory.

• Structural Engineering and Mechanics
• /
• 제67권3호
• /
• pp.291-300
• /
• 2018

In this work, a new trigonometry theory of shear deformation is developed for the static analysis of thick isotropic beams. The number of variables used in this theory is identical to that required in the theory of Euler-Bernoulli, sine function is used in the displacement field in terms of the coordinates of the thickness to represent the effects of shear deformation. The advantage of this theory is that shear stresses can be obtained directly from the relationships constitute, while respecting the boundary conditions at the free surface level of the beam. Therefore, this theory avoids the use of shear correction coefficients. The differential equilibrium equations are obtained using the principle of virtual works. A thick isotropic beam is considered, whose numerical study to show the effectiveness of this theory.

• 여성건강간호학회지
• /
• 제10권2호
• /
• pp.109-118
• /
• 2004

Purpose: The purpose of this study was to develop a specialized education curriculum aimed at helping nurses prepare for running and managing a Maternal-Child Health Center (Postpartum Care Center). Method: This study was conducted by an academy and industry joint research group consisting of professors of Nursing, and nurses actually running a Postpartum Care Center. The group compiled job descriptions of nursing through document research, interviews and observation during site visits, surveys, and seminars. They then performed a feasibility study and developed the final curriculum. Result: The education curriculum is a 32-week(2semester) program compromised of a theory part (12 credits, 180 hours) covering maternal and infant care and business start-up and field practice (3 credits, 45 hours). Courses in the theory part include an antenatal care, overview and details of maternal care, starting a business and its management. Of these courses, the overview of a maternal care course was developed with web-based contents. Field practice is designed to give students opportunities to visit Postpartum Care Centers, observe the care provided, and get hands-on experience. Conclusion: The specialized education curriculum is a 32-week course comprised of 12 credits on theory of antenatal care, overview and details of maternal care, infant care, starting and operating a business and 3 credits of field practice.

• KCI Concrete Journal
• /
• 제11권3호
• /
• pp.5-17
• /
• 1999

In recent years. the concept of the modified compression field theory (MCFT) was develped and applied to the analysis of reinforced concrete beams subjected to shear, moment, and axial load. Although too complex for regular use in the shear design or beams. the procedure has value in its ability to provide a rational method of anlysis and design for reinforced concrete members. The objective of this paper is to review the MCFT and apply it for the prediction of the response and shear strength of reinforced concrete beams A Parametric analysis was Performed on a reinforced T-section concrete beam to evaluate and compare the effects of concrete strength. longitudinal reinforcement ratio shear reinforcement ratio, and shear span to depth ratio in two different approaches the MCFT and the ACI code. The analytical study showed that the concrete contribution to shear strength by the MCFT was higher than the one by the ACI code in beams without stirrups, while it was lower with stirrups. On the other hand. shear reinforcement contribution predicted by the MCFT was much higher than the one by the ACI code. This is because the inclination angle of shear crack is much smaller than 45$^{\circ}$assumed in the ACI code.

• Structural Engineering and Mechanics
• /
• 제51권5호
• /
• pp.867-891
• /
• 2014

An equivalent single layer trigonometric shear deformation theory taking into account transverse shear deformation effect as well as transverse normal strain effect is presented for static flexure of cross-ply laminated composite and sandwich plates. The inplane displacement field uses sinusoidal function in terms of thickness coordinate to include the transverse shear deformation effect. The cosine function in thickness coordinate is used in transverse displacement to include the effect of transverse normal strain. The kinematics of the present theory is much richer than those of the other higher order shear deformation theories, because if the trigonometric term (involving thickness coordinate z) is expanded in power series, the kinematics of higher order theories (which are usually obtained by power series in thickness coordinate z) are implicitly taken into account to good deal of extent. Governing equations and boundary conditions of the theory are obtained using the principle of virtual work. The closed-form solutions of simply supported cross-ply laminated composite and sandwich plates have been obtained. The results of present theory are compared with those of the classical plate theory (CPT), first order shear deformation theory (FSDT), higher order shear deformation theory (HSDT) of Reddy and exact three dimensional elasticity theory wherever applicable. The results predicted by present theory are in good agreement with those of higher order shear deformation theory and the elasticity theory.

• 대한간호학회지
• /
• 제49권5호
• /
• pp.505-514
• /
• 2019

Purpose: This study aimed to introduce and elucidate changes in Strauss and Corbin's grounded theory and discuss its application to the field of nursing in South Korea. Methods: The changes in grounded theory by Strauss and Corbin were examined through a literature review of grounded theory from its inception. Results: Strauss and Corbin acknowledged their philosophical backgrounds of symbolic interactionism and pragmatism; however, their methodology based on positivism overwhelmed their epistemology and ontology. This inconsistency has been represented by the coding paradigm and the premise of "emergent from the data." In the revised version of Basics, Strauss and Corbin modified their theory to weaken the coding paradigm and strengthen the strategies for the development of substantive theory. Conclusion: Strauss and Corbin's revised grounded theory did not fully address the inconsistency of their epistemology and ontology between their acknowledgement and methodology. However, these changes constitute a meaningful step toward resolving inconsistencies and highlight the development of substantive theory. This has implications for Korean nursing researchers who have utilized methodologies in grounded theory with dogmatic approaches; grounded theory, with its evolving nature, is not a finalized method and calls for open approaches for the development of a grounded theory that fits Korean nursing.

• Korean Journal of Mathematics
• /
• 제23권3호
• /
• pp.323-326
• /
• 2015

We prove that if a subfield of the Hilbert class field of an imaginary quadratic field k meets the anticyclotomic $\mathbb{Z}_p$-extension $k^a_{\infty}$ of k, then it is contained in $k^a_{\infty}$. And we give an example of an imaginay quadratic field k with ${\lambda}_3(k^a_{\infty}){\geq}8$.