• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.16 no.4
• /
• pp.36-44
• /
• 2007

This paper is focused on the optimum design for decreasing volume and increasing reliability of multi-stage gear drive. For the optimization on volume and reliability, multi-objective optimization is used. The genetic algorithm is introduced to multi-objective optimization method and it is used to develop the optimum design program using exterior penalty function method to solve the complicated subject conditions. A 5 staged gear drive(geared motor) is chosen to compare the result of developed optimum design method with the existing design. Each of the volume objective, reliability objective, and volume-reliability multi-objectives are performed and compared with existing design. As a result, optimum solutions are produced, which decrease volume and increase reliability. It is shown that the developed design method is good for multi-stage gear drive design.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11a
• /
• pp.400.1-400
• /
• 2002

This paper presents an optimum design of rotor-bearing system using a hybrid method to compute the solutions of optimization problem. The present hybrid algorithm, namely Enhanced Artificial Life Algorithm(EALA), is a synthesis of an artificial life algorithm(ALA) and the random tabu search(R-tabu) method. We applied EALA to the optimum design of rotor-shaft system supported by the floating ring journal bearings. (omitted)

• Steel and Composite Structures
• /
• v.14 no.5
• /
• pp.431-451
• /
• 2013

The Big Bang-Big Crunch (BB-BC) optimization algorithm is developed for optimal design of non-linear steel frames with semi-rigid beam-to-column connections. The design algorithm obtains the minimum total cost which comprises total member plus connection costs by selecting suitable sections. Displacement and stress constraints together with the geometry constraints are imposed on the frame in the optimum design procedure. In addition, non-linear analyses considering the P-${\Delta}$ effects of beam-column members are performed during the optimization process. Three design examples with various types of connections are presented and the results show the efficiency of using semi-rigid connection models in comparing to rigid connections. The obtained optimum semi-rigid frames are more economical solutions and lead to more realistic predictions of response and strength of the structure.

• International Journal of Precision Engineering and Manufacturing
• /
• v.6 no.4
• /
• pp.73-77
• /
• 2005

Linear motor has been considered to be the most suitable electric machine for linear control with high speed and high precision. Thrust of linear motor is one of the important factors to specify motor performance. Maximum thrust can be obtained by increasing the magnitude of current in conductor and is relative to the sizes of conductor and magnet. However, the magnitude of current and the size of conductor have an effect on temperature of linear motor. Therefore, it is practically important to find optimum design that can effectively maximize thrust of linear motor within limited range of temperature. Finite element analysis was applied to calculate thrust and numerical solutions were compared with experiments. The temperature of the conductor was calculated from the experimentally determined thermal resistance. The ADPL of ANSYS was used for the optimum design process, which is commercial finite element analysis software. Design variables and constraints were chosen based on manufacturing feasibility and existing products. As a result, it is shown that temperature of linear motor plays an important role in determining optimum design.

• Journal of Advanced Marine Engineering and Technology
• /
• v.13 no.2
• /
• pp.43-63
• /
• 1989

Various kinds of corrosion prevention methods have been developed. It is known that the method of electrochemical protection is more effective and economical than any other method on the large scale metal structures in corrosive solutions. Strong acid solutions such as nitric and sulfuric acid solutions are often used in industries, and the expensive stainless steel is almost exclusively used for the equipment that comes in contact with such acid solutions. However, it is more reasonable that carbon steel is used rather than stainless steel depending upon concentration of those acid solutions from the economical viewpoint. In this study, the typical strong acid solution such as nitric and sulfuric acid solutions are chosen for the experiment and the selected materials of specimen are the stainless steels of SUS 304L and SUS 316L, the carbon steels of SS 41, SM 50 and RA 32, and highly pure lead. Electrochemical protection diagrams can be drawn with data from the external cathodic and anodic polarization curves of SUS 304L, SUS 316L and SM 50 steels in 5-60% nitric acid solutions and from those polarization curves of SS 41, RA 32, SM 50 and SUS 316L steels, and highly pure lead in 2.5-98% sulfuric acid solutions at the slow scanning rate. The data obtained with using the determination method of the optimum cathodic protection potential, the Tafel extrapolation method and the characteristics of anodic polarization curves. The main results obtained from the diagrams are as follows: 1) In nitric acid solution : (1) Corrosion potentials exist in each of those corrosion zones on the stainless steels in the lower concentration than about 12% solutions and on the high tensile strength steels in the lower concentration than about 30% solutions, but the corrosion current (density) in each zone is small on the above mentioned former steels and large on the latter ones. (2) The stainless steels can be self-passivated in the higher concentration than 15% solutions, and the high tensile strength steels gives rise to the same phenomenon in the higher concentration than 35% solutions. (3) The stainless steels in the lower concentration than 60% solutions and the high tensile strength steels in the higher concentration than 35% solutions can be used without protection, but the latter steels must ve protected anodically in the lower conccentration than about 30% solutions. 2) In sufuric acid solution : (1) The carbon steels can be self-passivated in the higher concentration than 45% solutions, and the SUS 316L steel in higher concentration than 75% solutions and the lead in all concentration solutions also gives rise to the same phenomenon. (2) The lead in the lower concentration than 80% solutions and the SUS 316L steel in the higher concentration than 80% solutions can be used without protection. (3) The carbon steels in the higher concentration than 50% solutions also can be used without protecting economically, but the SUS 316L steel in the 20-70% solutions are considerably corrosive without protecting anodically.

• Management Science and Financial Engineering
• /
• v.11 no.2
• /
• pp.45-60
• /
• 2005

This paper investigates the application of the computer method COMSOAL (Computer Method of Sequencing Operations for Assembly Lines) to the process routing (PR) problem with multiple objectives. In any computer aided process planning (CAPP) system, one of the most critical activities for manufacturing a part could be to generate the sequence that optimizes production time, production cost, machine utilization or with multiple these criteria. The COMSOAL has been adopted to find the optimum sequence of operations that optimizes two major conflicting criteria : production cost and production quality. The COMSOAL is here slightly modified to simultaneously generate and evaluate a set of possible solutions (called as population) instead of processing a solution stepwise in each iteration. The significant features of the COMSOAL include : no parameters settings needed, and a guarantee of feasible solutions. Experimental results show that COMSOAL is a simple but powerful method to quickly generate multiple feasible solutions which are as good as the ones obtained from several other well-known process routing algorithms.

• Journal of environmental and Sanitary engineering
• /
• v.13 no.1
• /
• pp.174-184
• /
• 1998

Biosorption characteristics were investigated to discuss the use of agar entrapped Spirulina to remove of heavy metal ions from polluted waters. Agar immobilized algae were used as bioadsorbent in continuous reactor for heavy metal ions removal. The process solution contains Pb, Cu, and Cd as single ion and binary ions. In the adsorption of single heavy metal ions by agar immobilized Spirulina, the adsorption reached within 1hr and observed diffusion limitation differed from the free algal cell adsorption. The optimum pH for the adsorption of heavy metals was 4.5 but the influence of pH decreased less than that of free algal cell. Also, the adsorption characteristics of single heavy metal ions with agar immobilized Spirulina fitted the BET isotherm. Both of experiments of free algal cell and agar immobilized algae showed higher removal efficiency in the single ion solutions than binary ions solutions. The experimental results in the packed column with agar immobilized algae were over 90% of removal efficiency for the Pb, Cu, and Cd in single ion solutions.

• Journal of applied mathematics & informatics
• /
• v.9 no.1
• /
• pp.197-211
• /
• 2002

In this paper, we propose a multi-Criteria decision making approach to address the problem of finding the best possible solution in credit unions. Sensitivity analysis on the priority structure of the goals has been performed to obtain all possible solutions. The study uses the Euclidean distance method to measure distances of all possible solutions from the identified ideal solution. The possible optimum solution is determined from the minimum distance between the ideal solution and other possible solutions of the Problem.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.9
• /
• pp.149-157
• /
• 2004

This paper presents a new method for hi-objective optimization. Ordinary weighted sum method is easy to implement, but it has two significant drawbacks: (1) the solution distribution by the weighted sum method is not uniform, and (2) the method cannot determine any solutions that reside in non-convex regions of a Pareto front. The proposed adaptive weighted sum method does not solve a multiobjective optimization in a predetermined way, but it focuses on the regions that need more refinement by imposing additional inequality constraints. It is demonstrated that the adaptive weighted sum method produces uniformly distributed solutions and finds solutions on non-convex regions. Two numerical examples and a simple structural problem are presented to verify the performance of the proposed method.

• Ocean Systems Engineering
• /
• v.13 no.4
• /
• pp.325-347
• /
• 2023

The present work investigates the wave generation and propagation in a 2-D wave flume to assess the effect of wave reflection for varying beach slopes by using a numerical tool based on computational fluid dynamics. At first, a numerical wave flume (NWF) is created with different mesh sizes to select the optimum mesh size for time efficient simulation. In addition, different beach slope conditions are introduced such as 1:3, 1:5 and numerical beach at the far end of the NWF to optimize the wave reflection solutions. In addition, several parameters are analysed in order to optimize the solutions. The developed numerical model and its key findings are compared with analytical and experimental surface elevation results and it reveals a good correlation. Finally, the recommended numerical solutions are validated with the experimental findings.