• Structural Engineering and Mechanics
• /
• v.45 no.5
• /
• pp.631-641
• /
• 2013

In this paper, the problem of axisymmetric deformation of the circular membrane fixed at its perimeter under the action of uniformly-distributed loads was resolved by exactly using power series method, and the solution of the problem was presented. An investigation into the so-called Hencky transformation was carried out, based on the solution presented here. The results obtained here indicate that the well-known Hencky solution is, without doubt, correct, but in the published papers the statement about its derivation is incorrect, and the so-called Hencky transformation is invalid and hence may not be extended to use as a general mathematical method.

• Journal of the Korean Society of Costume
• /
• v.52 no.3
• /
• pp.19-27
• /
• 2002

This paper surveys the mordanting and dyeing properties of Sophora japonica L. Appropriate extraction, dyeing and mordanting condition of Sophora japonica L. were determined, and the effect of mordanting method on dye uptake and color fastness of dyed fabric was investigated. The maximum absorbance of Sophora japonica L. solution was 367.6mn, rutin solution was 365.6mn. The color of Sophora japonica L. solution was affected at pH 2 and pH 8~9. The optimum temperature to extract Sophora japonica L. was during 1 hour in 8$0^{\circ}C$. The effective dyeing temperature and time of silk were 10$0^{\circ}C$, 60min. K/S value of dyeing fabrics was increased by pre-mordanting treatment, especially Fe, Sn, Cr. In the case of Sophora japonica L. light fastness was increased by Fe mordanting. Perspiration fastness was better in acidic solution than that in alkaline solution. Fastness to rubbing and dry-cleaning were good in general.

• International Journal of Aeronautical and Space Sciences
• /
• v.9 no.2
• /
• pp.79-86
• /
• 2008

High performance direct-iterative hybrid linear solver for large scale finite element problem is developed. Direct solution method is robust but difficult to parallelize, whereas iterative solution method is opposite for direct method. Therefore, combining two solution methods is desired to get both high performance parallel efficiency and numerical robustness for large scale structural analysis problems. Hybrid method mentioned in this paper is based on FETI-DP (Finite Element Tearing and Interconnecting-Dual Primal method) which has good parallel scalability and efficiency. It is suitable for fourth and second order finite element elliptic problems including structural analysis problems. We are using the hybrid concept of theses two solution method categories, combining the multifrontal solver into FETI-DP based iterative solver. Hybrid solver is implemented for our general structural analysis code, IPSAP.

• Corrosion Science and Technology
• /
• v.14 no.5
• /
• pp.207-212
• /
• 2015

The purpose of this research was to synthesize fluorine modified waterborne polyurethane dispersion (F-WPU) by soap-free (internal emulsifier) emulsion polymerization techniques, to prepare coating solution based on fluorine modified waterborne polyurethane dispersion (F-WPU) and to compare the chemical and thermo-mechanical properties on the electrogalvanized steel sheet. Environmentally friendly F-WPU was prepared with a fluorinated polyol containing 60 wt% of fluorine. There are various ways of combining a wide variety of fluorinated polyols and diisocyanate to exhibit novel properties of waterborne polyurethane dispersion. Components of coating solution were largely divided into 4 kinds i.e., F-WPU, acrylic emulsion, silane coupling agent, and colloidal silicate. F-WPU coating solution on the electro-galvanized steel sheet showed excellent properties of corrosion resistance, alkali resistance and heat resistance, as compared to other coating solutions using a general waterborne resin. The F-WPU coating solution's reliable effects are possibly due to the fluorine atoms incorporated even in a small amount of F-WPU.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.17 no.8
• /
• pp.1883-1897
• /
• 1993

Interactive computer-aided analysis of mechanical systems has recently been undergoing an evolution due to highly efficient computer graphics. The industrial implementation of state-of-the-art analytical developments in mechanisms has been facilitated by computer-aided design packages because these rigid-body mechanism analysis programs dramatically reduce the time required for linkage design. This paper proposes a component modular approach to computeraided kinematic motion analysis for general planar multiloop mechanisms. Most multiloop mechanisms can be decomposed into serveral components. The kinematic properties (position, velocity, and acceleration) of every node can then be determined from the kinematic analysis of the corresponding component modules by a closed-form solution procedure. In this paper, 8 types of modules are defined and formulations for kinematic analysis of the component modules are derived. Then a computer-aided kinematic analysis program is developed using the proposed approach and the solution procedure of an example shows the effectiveness and accuracy on the approach.

• Journal of Korean Institute of Industrial Engineers
• /
• v.28 no.1
• /
• pp.14-24
• /
• 2002

We focus on resource allocation planning in container terminal operation planning problems and present network design model and genetic algorithm. We present a network design model in which arc capacities must be properly dimensioned to sustain the container traffic. This model supports various planning aspects of container terminal and brings in a very general form. The integer programming model of network design can be extended to accommodate vertical or horizontal yard configuration by adding constraints such as restricting the sum of yard cranes allocated to a block of yards. We devise a genetic algorithm for the network design model in which genes have the form of general integers instead of binary integers. In computational experiments, it is found that the genetic algorithm can produce very good solution compared to the optimal solution obtained by CPLEX in terms of computation time and solution quality. This algorithm can be used to generate many alternatives of a resource allocation plan for the container terminal and to evaluate the alternatives using various tools such as simulation.

• Structural Engineering and Mechanics
• /
• v.72 no.5
• /
• pp.617-629
• /
• 2019

Based on the finite element method of traditional straight Euler-Bernoulli beams and the coupled relations between linear displacement and angular displacement of a pre-twisted Euler-Bernoulli beam, the shape functions and stiffness matrix are deduced. Firstly, the stiffness of pre-twisted Euler-Bernoulli beam is developed based on the traditional straight Euler-Bernoulli beam. Then, a new finite element model is proposed based on the displacement general solution of a pre-twisted Euler-Bernoulli beam. Finally, comparison analyses are made among the proposed Euler-Bernoulli model, the new numerical model based on displacement general solution and the ANSYS solution by Beam188 element based on infinite approach. The results show that developed numerical models are available for the pre-twisted Euler-Bernoulli beam, and which provide more accurate finite element model for the numerical analysis. The effects of pre-twisted angle and flexural stiffness ratio on the mechanical property are investigated.

• Coupled systems mechanics
• /
• v.11 no.2
• /
• pp.151-166
• /
• 2022

Peltier cells have low efficiency, but they are becoming attractive alternatives for affordable and environmentally clean cooling. In this line, the current article develops closed-form and semianalytical solutions to improve the temperature distribution of Bi₂Te₃ thermoelements. From the distribution, the main objective of the current work-the optimal electric intensity to maximize cooling-is inferred. The general one-dimensional differential coupled equation is integrated for linear and quadratic geometry of thermoelements, under temperature constant properties. For a general shape, a piece-wise solution based on heat flux continuity among virtual layers gives accurate analytical solutions. For variable properties, another piece-wise solution is developed but solved iteratively. Taking advantage of the formulae, the optimal intensity is directly derived with a minimal computational cost; its value will be of utility for more advanced designs. Finally, a parametric study including straight, two linear, barrel, hourglass and vase geometries is presented, drawing conclusions on how the shape of the thermoelement affects the coupled phenomena. A specially developed coupled and non-linear finite element research code is run taking into account all the materials of the cell and using symmetries and repetitions. These accurate results are used to validate the analytical ones.

• Communications of the Korean Mathematical Society
• /
• v.31 no.1
• /
• pp.131-138
• /
• 2016

We determine the general solutions $f:\mathbb{R}^2{\rightarrow}\mathbb{R}$ of the functional equation f(ux-vy, uy+v(x+y)) = f(x, y)f(u, v) for all x, y, u, $v{\in}\mathbb{R}$. We also investigate both bounded and unbounded solutions of the functional inequality ${\mid}f(ux-vy,uy+v(x+y))-f(x,y)f(u,v){\mid}{\leq}{\phi}(u,v)$ for all x, y, u, $v{\in}\mathbb{R}$, where ${\ph}:\mathbb{R}^2{\rightarrow}\mathbb{R}_+$ is a given function.

• Journal of Korean Institute of Industrial Engineers
• /
• v.16 no.2
• /
• pp.109-117
• /
• 1990

In this paper we study a mathematical programming model for the single-card KANBAN system in a multi-stage capacitated general-type-structure production. Until now this production type setting has not been studied. The modeling of this problem results in a complex integer programming which can be modified to the more simple integer programming model. We present a heuristic method and some numerical examples. Though the presented method doesn't always find an optimal solution, this method guarantees to find a feasible solution. We expect this work to be practised in the real fields.