• 한국안전학회지
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• 제31권1호
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• pp.41-47
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• 2016

The rolling stock is composed of several cars. In order to operate in combination, it is necessary to connect the device, called coupler, between the rolling stocks. When the collision occurs between cars, couplers should be able to absorb the shock. Urban railway has used only rubber absorbers. But recently, the hydraulic buffer has been considered in general railway. In order to know the performance of the buffer it should be conducted to experiments. But whenever this combination change, we should experiments to know a lot of the dynamic behavior of each coupler. These experiments are generally replaced by the simulation, since a lot of time and cost consuming. The quasi-static map of hydraulic buffer obtained by the experiments is required for the simulation. However, the experiments for obtaining such a quasi-static map is costly and time consuming. In this paper, it proposes a method for deriving the quasi-static map of hydraulic buffer from the theoretical model.

• 한국기계가공학회지
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• 제1권1호
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• pp.133-140
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• 2002

The object of this paper is to predict the surface roughness using the experiment equation of surface roughness, which is developed with a full factorial design in turning. $3^3$ full factorial design has been used to study main and interaction effects of main cutting parameters such as cutting speed, feed rate, and depth of cut, on surface roughness. For prediction of surface roughness, the arithmetic average (Ra) is used, and stepwise regression has been used to check the significance of all effects of cutting parameters. Using the result of these, the experimental equation of surface roughness, which consists of significant effects of cutting parameters, has been developed. The coefficient of determination of this equation is 0.9908. And the prediction ability of this equation was verified by additional experiments. The result of that, the coefficient of determination is 0.9718.

• Journal of Computational Design and Engineering
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• 제3권1호
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• pp.1-13
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• 2016

The increase of consumer needs for quality metal cutting related products with more precise tolerances and better product surface roughness has driven the metal cutting industry to continuously improve quality control of metal cutting processes. In this paper, two different approaches are discussed. First, design of experiments (DOE) is used to determine the significant factors and then fuzzy logic approach is presented for the prediction of surface roughness. The data used for the training and checking the fuzzy logic performance is derived from the experiments conducted on a CNC milling machine. In order to obtain better surface roughness, the proper sets of cutting parameters are determined before the process takes place. The factors considered for DOE in the experiment were the depth of cut, feed rate per tooth, cutting speed, tool nose radius, the use of cutting fluid and the three components of the cutting force. Finally the significant factors were used as input factors for fuzzy logic mechanism and surface roughness is predicted with empirical formula developed. Test results show good agreement between the actual process output and the predicted surface roughness.

• Corrosion Science and Technology
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• 제12권3호
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• pp.132-141
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• 2013

This work is concerning a methodology of Ni-base superalloy development for a very high temperature gas-cooled reactor(VHTR) using design of experiments(DOE) and thermodynamic calculations. Total 32 sets of the Ni-base superalloys with various chemical compositions were formulated based on a fractional factorial design of DOE, and the thermodynamic stability of topologically close-packed(TCP) phases of those alloys was calculated by using the THERMO-CALC software. From the statistical evaluation of the effect of the chemical composition on the formation of TCP phase up to a temperature of 950 oC, which should be suppressed for prolonged service life when it used as the structural components of VHTR, 16 sets were selected for further calculation of the mechanical properties. Considering the yield and ultimate tensile strengths of the selected alloys estimated by using the JMATPRO software, the optimized chemical composition of the alloys for VHTR application, especially intermediate heat exchanger, was proposed for a succeeding experimental study.

• 한국정밀공학회지
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• 제26권8호
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• pp.104-111
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• 2009

In this paper, the gear design program is presented. The profile of gears is created using classical mathematic formulations. In each gear, a kinematic joint is applied and one can define the 20 contact condition between gear pairs. Initial and boundary conditions such as force, torque, velocity, acceleration, etc. can be set. Thus, it is possible to analyze dynamic characteristics of gear pairs such as reaction moment and the variation of angular velocity. In order to find the optimal profile of gear pairs, two optimization methods based on design of experiments are inserted in the program; One is the Taguchi method and the other is the response surface analysis method. To verify the program, the rack & pinion gear is created and analyzed. Simulation results show that the developed program is useful and result data is reliable.

• 동력기계공학회지
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• 제13권5호
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• pp.89-94
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• 2009

In this work, the optimal process has been designed by $L_9(3^4)$ orthogonal array and analysis of variance(ANOVA) for thermal-sprayed Ni-based hard coating. Ni-based hard coatings were fabricated by flame spray process on steel substrate. Then, the hardness test and observation of microstructure of the coatings were performed. The results of hardness test were analyzed by ANOVA. The ANOVA results demonstrated that the acetylene gas flow had the greatest effect on hardness of the coatings. The oxygen gas flow was found to have a neglecting effect. From these results, the optimal combination of the flame spray parameters could be predicted. The calculated hardness of the coatings by ANOVA was found to lie close to that of confirmation experimental result. Thus, it was considered that design of experiments design using orthogonal array and ANOVA was useful to determine optimal process of thermal-sprayed Ni-based hard coating.

• 한국정밀공학회지
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• 제19권7호
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• pp.88-96
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• 2002

High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feed rate, high-speed machining can give great advantages for the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining. Depth of cut, feed rate and spindle revolution are control factors. The effect of the control factors on machining accuracy is investigated using two-way factorial design.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.883-888
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• 2008

Various effluents generated in cooking processes contribute a great deal to indoor air pollution among many other indoor pollutants such as dusts from outdoor and carbon dioxide from human body. Kitchen exhaust hoods are not believed to exhaust indoor contaminants properly in many cases, while generating too much noise. Instead of focusing on individual products of kitchen hoods, we should address the problem by attacking the ventilation system as a whole including vertical shafts and building air-tightness. In this study, it is intended to investigate the pressure distribution along the vertical shaft depending on various system parameters, such as shaft size, concurrent hood usage rate, roof fan, inlet pressure loss, and outdoor temperature. The maximum static pressure in the vertical shaft has been obtained using the method of design of experiments and analyzed by the analysis of variance. The results can be used for the design of kitchen exhaust systems by analyzing the pressure distributions in vertical shafts.

• Transactions on Electrical and Electronic Materials
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• 제10권5호
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• pp.177-181
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• 2009

Employing statistical design of experiments, we have performed studies on the characterization of electrodes using $TiO_2$ and process variables in the fabrication process of nanocrystalline dye sensitized solar cell. Systematic experiment to identify the effects of process variables on cell's efficiency has based on broad-band absorption of light by tailor made organometallic dye molecules dispersed on a high surface of $TiO_2$. Employing statistical design of experiment on $TiO_2$ photoelectrode forming process, structural characterization of electrodes and process variable have been investigated. Through the statistical analysis we have found that the particle size of $TiO_2$ and the amount of PEG/PEO are significantly affecting on the cell efficiency. In addition, a significant amount of interaction exists between the particle size and the amount of PEG/PEO.

• 공업화학
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• 제35권4호
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• pp.346-351
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• 2024

Chemical reduction using catalysts and NaBH₄ presents a promising approach for reducing 4-nitrophenol contamination while generating valuable byproducts. Covalent organic frameworks (COFs) emerge as a versatile platform for supporting catalysts due to their unique properties, such as high surface area and tunable pore structures. This study employs design of experiments (DOE) to systematically optimize the synthesis of Cu embedded COF (Cu/COF) catalysts for the reduction of 4-nitrophenol. Through a series of experimental designs, including definitive screening, mixture method, and central composition design, the main synthesis parameters influencing Cu/COF formation are identified and optimized: MEL:TPA:DMSO = 0.31:0.36:0.33. Furthermore, the optimal synthesis temperature and time were predicted to be 195 ℃ and 14.7 h. Statistical analyses reveal significant factors affecting Cu/COF synthesis, facilitating the development of tailored nanostructures with enhanced catalytic performance. The catalytic efficacy of the optimized Cu/COF materials is evaluated in the reduction of 4-nitrophenol, demonstrating promising results in line with the predictions from DOE.