• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.206-209
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• 2003

함금속 염료는 이들 염료들의 우수한 일광견뢰도 때문에 섬유산업에서 광범위하게 사용되고 있다. 함금속 염료에 사용되는 금속으로는 크롬, 코발트 및 구리 등이 이용되고있다. 금속 착물은 주로 안료뿐만 아니라 산성, 직접 및 반응성 염료에서 사용하고 있다[1,2] 섬유 염색에서 중요한 부분으로는 염색폐수의 방출에 있다 [3]. 특히, 몇몇 염료들의 발암성물질과, 환원에 의한 아조 그룹의 파괴 등으로 발성하는 아민류가 심각한 환경문제로 관심을 갖고있다[4]. (중략)

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.10a
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• pp.235-237
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• 2005

• Structural Engineering and Mechanics
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• v.9 no.1
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• pp.37-50
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• 2000

Very few studies on orthotropic circular disks or rings under diametrical loadings are conducted because of difficulties in treatment. This paper shows analytical solutions and gives the distributions of stresses and displacements by using Lekhnitskii's complex variable method. Several numerical results are shown by graphical representation.

• Journal of applied mathematics & informatics
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• v.16 no.1_2
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• pp.323-336
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• 2004

We consider the application of complex variable method to elastic problem and investigate the nonlinear effect of finite torsion of a compressible elastic composite layer. We obtain that as a result of finite deformation approach, a tube subjected to torsion decreases in radius giving rise to a “hold effect”.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.453-458
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• 1996

In reinforced concrete structure, it is very important to secure ductile performance of column because the columns become brittle failure and cause the collapse of an entire structure and the damage of human life. This study is intending to seek the quantity of transverse steels in square reinforced concrete columns which is derived from moment-curvature analysis of cross section about various arrangements of transverse steel and the ratio of axial force and to propose the design method to secure the sufficient ductile behavior subjected to complex loading.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.927-932
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• 2001

Rubber has high damping and can be formed as various shape according to specific purpose. So, Rubber has widely used as isolation mounts. However, there are still a lot of difficulties in understanding of static and dynamic characteristics of compressed and shear rubber mounts. In this paper, Static characteristics of the rubber isolation mount are observed by the analytical method and FEM. Also dynamic characteristics of rubber mount under compression and shear strain are investigated.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.591-604
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• 2009

This paper presents some important issues in modeling rock behaviour around an underground opening at depth which characterized as stress-induced fractural failure of rock. Unlike other conventional modeling approaches, stress-induced rock failure is highly complex process due to its own heterogeneous and discrete natures. Because of this complexity, many researchers has been struggled to mimic such processes as close as possible to reality with various approaches in both analytical, and numerical approaches for past few decades. Such approaches which are based on continuum mechanics, analytical fracture mechanics, and DEM(Discrete Element Method) were explored in this paper, and fundamental shortcomings for each approaches were illustrated here. In addition, DEM approach using $PFC^{2D}$(Particle Flow Code) was also implemented and illuminated in this paper and discuss the improvement and considerations for the future research.

• Steel and Composite Structures
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• v.17 no.5
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• pp.721-734
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• 2014

In the current study, we consider a new class of analytical periodic solution for free nonlinear vibration of mechanical systems. Hamiltonian approach is applied to analyze nonlinear problems which occur in dynamics. The proposed method doesn't have the limitations of the classical methods and leads us to a high accurate solution by only one iteration. Two well known examples are studied to show the convenience and effectiveness of this approach. Runge-Kutta's algorithm is also applied and the results of it are compared with the Hamiltonian approach. High accuracy of the proposed approach reveals that the Hamiltonian approach can be very useful for other nonlinear practical problems in engineering.

• Geomechanics and Engineering
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• v.16 no.6
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• pp.609-618
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• 2018

A new mechanical model for predicting the vibration of a pipe pile embedded in longitudinally layered visco-elastic media with radial inhomogeneity is proposed by extending Novak's plain-strain model and complex stiffness method to consider viscous-type damping. The analytical solutions for the dynamic impedance, the velocity admittance and the reflected signal of wave velocity at the pile head are also derived and subsequently verified by comparison with existing solutions. An extensive parametric analysis is further performed to examine the effects of shear modulus, viscous damping coefficient, coefficient of disturbance degree, weakening or strengthening range of surrounding soil and longitudinal soft or hard interbedded layer on the velocity admittance and the reflected signal of wave velocity at the pile head. It is demonstrated that the proposed model and the obtained solutions provide extensive possibilities for practical application compared with previous related studies.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.9
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• pp.1320-1327
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• 2004

An efficient boundary-based technique is developed for addressing shape design sensitivity analysis in supercavitating flow problem. An analytical sensitivity formula in the form of a boundary integral is derived based on the continuum formulation for a general functional defined in potential flow problems. The formula, which is expressed in terms of the boundary solutions and shape variation vectors, can be conveniently used for gradient computation in a variety of shape design in potential flow problems. While the sensitivity can be calculated independent of the analysis means, such as the finite element method (FEM) or the boundary element method (BEM), the FEM is used for the analysis in this study because of its popularity and easy-to-use features. The advantage of using a boundary-based method is that the shape variation vectors are needed only on the boundary, not over the whole domain. The boundary shape variation vectors are conveniently computed by using finite perturbations of the shape geometry instead of complex analytical differentiation of the geometry functions. The supercavitating flow problem is chosen to illustrate the efficiency of the proposed methodology. Implementation issues for the sensitivity analysis and optimization procedure are also addressed in this flow problem.