• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.1 s.244
• /
• pp.18-25
• /
• 2006

The purpose of this research work is to demonstrate a successful application of hybrid-mixed formulation and nodeless degrees of freedom in developing a very accurate in-plane curved beam element for free vibration analysis. To resolve the numerical difficulties due to the spurious constraints, the present element, based on the Hellinger-Reissner variational principle and considering the effect of shear deformation, employed consistent stress parameters corresponding to cubic displacement polynomials with additional nodeless degrees. The stress parameters were eliminated by the stationary condition, and the nodeless degrees were condensed by Guyan Reduction. Several numerical examples indicated that the property of the mass matrix as well as that of the stiffness matrix have a great effect on the numerical performance. The element with consistent mass matrix produced best results on convergence and accuracy in the numerical analysis of Eigenvalue problems. Also, the higher-order mixed curved beam element showed a superior numerical behavior for the free vibration analyses.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2006.11a
• /
• pp.426-426
• /
• 2006

선박이 천 흘수 및 수로를 운항하는 경우 바닥과 벽면의 영향으로 인해 선체침하 및 비대칭적인 힘이 선체 주위에 발생하여 바닥이나 다른 선박 혹은 수로의 벽에 충돌하는 현상이 발생한다. 특히, 수로가 많은 유럽이나 북미를 운항하는 해운회사와 항해사들은 선박의 충돌을 방지하기 위해서 중요한 문제로 다루고 있다. 따라서, 본 연구에서는 선박의 안전한 항해를 위해 수치해석을 이용하여 선박과 벽면 사이에 발생하는 유체역학적 힘, 즉 Sway force와 Yaw Moment를 정성적으로 추정하고자 하였다. 천 흘수 유동 해석용 프로그램을 작성하였으며, 검증을 위해서 Wigley 선형에 적용하여 h/T별로 계산을 수행하여 시험결과와 비교하였다. 그리고, 벽면효과를 해석 할 수 있는 프로그램을 작성하여 실적선인 원유운반선 2척에 대하여 3가지 파라메터, 즉 선속, 수심 그리고 선박과 벽면 사이 거리의 변화에 따른 다양한 계산을 수행하였다. 계산된 결과는 시험결과 및 기 발표된 수치해석 결과와 비교하였다. 기 발표된 논문에서는 시험결과와 계산결과가 상이한 결론을 보여 주었는데, 그 이유는 수치해석에 있어서 자유표면 문제를 선형화된 자유표면 조건식을 사용한 부분을 가장 큰 이유로 언급하였다. 하지만, 본 연구의 결과는 Sway force와 Yaw Moment가 기 발표된 논문의 시험결과와 정성적으로 일치함을 보여 주었다. 본 연구를 통해 수치해석 방법으로 선박에 작용하는 비대칭 유동에 대한 유체역학적인 힘을 정성적으로 추정할 수 있었고, 제한된 수로에서 선박의 조종성 예측 및 수로 설계시 유용한 정보를 제공할 수 있을 것이라고 판단되어 진다.

• Journal of the Society of Naval Architects of Korea
• /
• v.37 no.4
• /
• pp.66-74
• /
• 2000

In this paper, hydroelastic responses of the very large floating structure are studied based on the linear potential theory. A theoretical method is developed to analyze the hydroelastic reponses of very large floating structures(VLFS) using the pressure distribution method and the modal expansion method. The singularities distributed on a zero draft plate at the free surfaces and hydrodynamic pressures are evaluated. The deflections of structure are expanded approximately in terms of natural mode functions of free-free beam. The calculated items are pressure distributions. vertical motions, hydrodynamic coefficients and bending moments of VLFS. The numerical results are compared with those measured by experiments.

• International Area Studies Review
• /
• v.13 no.3
• /
• pp.121-144
• /
• 2009

Consumers generally have different country images and purchasing patterns about products made in different countries. The essence of consumer behavior lies in psychological image on consumers' mind rather than actual characteristics of product itself. The current study examines how much country of origin influences consumers' purchase intentions focusing on Mexican products by consumers between Korea and the U.S. after establishment of NAFTA. The result of the study shows that there exists significant differences between Korean and the U.S. consumers' attitudes on purchasing Mexican products by structural equation modeling analyses.

• Journal of Korea Water Resources Association
• /
• v.49 no.12
• /
• pp.961-969
• /
• 2016

Due to the recent requirement of installing low-head structures considering environmental aspects, various types of fixed weir have been suggested. However, the design guideline of transverse structures for practical application is very limited. The purpose of the present study is to analyze the hydraulic properties of the fixed weirs installed at the small and middle sized rivers of Korea depending on the physical specifications to provide fundamental data that may be reflected to the design of a low-head fixed weir considering the relevant environmental aspects. The basic discharge coefficient of slope-type and step-type weirs depending on change of crest was estimated, and a stage-discharge curve was developed. In addition, the flow properties under free flow and submerged flow conditions were analyzed by varying the hydraulic conditions such as discharge and crest.

• The Journal of the Korea Contents Association
• /
• v.14 no.4
• /
• pp.456-466
• /
• 2014

This is a study of George Lindbeck's postliberalism that views religion as a cultural-linguistic approach. Knowing that the conceptual-propositional approach of the traditional Christian theology and the experiential-expressive approach of liberalism cannot be a solution for the post-modem religious phenomenon, George Lindbeck proposes an alternative. He proposes a cultural-linguistic approach to overcome the previous approaches. The first insight of Lindbeck's postliberalism is to understand religion as culture or language, because human beings become acquainted with a religion as they learn a language. The second insight comes out of the first, to understand doctrine as grammar. If we understand religion and doctrine this way the troubles and conflicts among religions will be resolved naturally, because each religion can be interpreted in its own system just as a language cannot be said to be good or bad, right or wrong. This approach makes several contributions as follows: it promotes a dialogue among religions, it emphasizes practice; and it preserves the Bible as an authoritative theological text. However it also brings many limitations as follows: it emphasizes the church's interpretation rather than the text's own interpretation; it views the truth simply as coherence; it promotes radical relativism and elitism; and through theological eschatology he makes his theory return to a propositionalism. Accordingly, the researcher concludes that Lindbeck's cultural-linguistic theory of religion is not an alternative that overcomes the limitations of theological conservativism and liberalism.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.17 no.1
• /
• pp.21-30
• /
• 2004

This study deals with free vibrations of laminated composite structures with a channel section using finite element method. In this paper, the mixed finite element method using Lagrangian and Hermite interpolation functions is adopted and a high-order plate theory is used to analyze laminated composite non-prismatic folded plates with a channel section more accurately for free vibration. The theory accounts for parabolic distribution of the transverse shear stress and requires no shear correction factors supposed in the first-order plate theory. An 32×32 matrix is assembled to transform the system element matrices from the local to global coordinates using a coordinate transformation matrix, in which an eighth drilling degree of freedom (DOF) per node is appended to the existing 7-DOF system. The results in this study are compared with those of available literatures for the conventional and first-order plate theory. Sample studies are carried out for various layup configurations and length-thickness ratio, and geometric shapes of plates. The significance of the high-order plate theory in analyzing complex composite structures with a channel section is enunciated in this paper.

• Sijohaknonchong
• /
• v.26
• /
• pp.243-261
• /
• 2007

In this study, I have looked though the Sijo made by Sowol and Jiyoung who were the frontiers of the Korean modern poetry. Through this study, I've tried to research the relationship between the free verse and their versifying Sijo. Sowol made the eight Sijo : six Sijo made in his early days. and the others made in later days. Sowol's early free verse tended to show the regular form. Although his 6 Sijo maintained the traditional form, he tried to make the formal changes. But the subject of those were in the way of view points of old Sijo. But the rest two Sijo strongly showed the problem of reality. Jiyoung made the 9 Sijo in his early days. But Jiyoung's is different from Sowol's. Jiyoung tried to make a new way of expressing the poetic images while Sowol was focused on the formal changes. Also, his final work 'Eun' had the feature of fixed form of verse. Through the research mentioned above, I confirmed that their tries to make the fixed form of verse were the background of developing and pioneering their free verse.

• Bulletin of the Society of Naval Architects of Korea
• /
• v.27 no.4
• /
• pp.51-57
• /
• 1990

There exist residual stresses and deformations in welded structures because of nonuniform temperature distribution. The thermal elasto-plastic analysis is necessary to describe the behavor of the structure during welding. In this paper, we calculated the residual stresses and deformations of the welded beam using the I-dimensional layered beam theory. In the previous 1-dimensional analyses, there were restrictions that the equilibrium conditions which were effective only on beams with infinite length were used, and the boundary conditions could not be considered adequately. But, the layered beam theory based on the incremental finite element method, can overcome these restrictions. On the other hand, in the 2-dimensional analysis, the computing time is large because of many degrees of freedom, and there was inaccuracy in the calculation of welding deformations. However, the layered beam theory can take into account the variation of properties along the depth, and can reduce the degrees of freedom considerably in comparision with the 2-dimensional analysis, and shows good agreement with the experiments.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.45 no.5
• /
• pp.376-385
• /
• 2017

In this paper, a method for the estimation of structural displacements using structure's mode shapes and accelerations is suggested to reduce the disadvantages of acceleration time integration method. Acceleration time integration method requires accurate information on initial conditions, and errors caused by noise can be accumulated during time integration. To avoid these problems, the method for the estimation of structural displacements based on mode superposition method is developed and two vibration experiments for cantilever beam are conducted to verify this method. Static displacements and dynamic displacements of beam structure are estimated using measured accelerations from experiments and mode shapes of cantilever beam, and they are compared with measured displacements using laser displacement sensor. From these results, the validity and usefulness of this method are verified.