Noise Reduction of Muffler by Optimal Design

Oh, Jae-Eung,Cha, Kyung-Joon The Korean Society of Mechanical Engineers 2000 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.14 No.9

This paper proposes an optimal design scheme to improve the muffler's capacity of noise reduction of the exhaust system by combining the Taguchi method and a fractional factorial design. As a measuring tool for the performance of a muffler, the performance prediction software which is developed by Oh, Lee and Lee (1996) is used. In the first stage of a design, the length and radius of each component of the current muffler system are selected as control factors. Then, the $L_{18}$ table of orthogonal arrays is adopted to extract the effective main factors. In the second stage, the fractional factorial design is adopted to take interactions into consideration, which the $L_{18}$ table of orthogonal arrays can not consider. For an optimal design, the $L_{27}$ table of orthogonal arrays with main and interaction effects is proposed and the noise factors such as temperature, background noise and humidity are analyzed for more efficient design simultaneously.

Using Taguchi design of experiments for the optimization of electrospun thermoplastic polyurethane scaffolds

Nezadi, Maryam,Keshvari, Hamid,Yousefzadeh, Maryam Techno-Press 2021 Advances in nano research Vol.10 No.1

Electrospinning is a cost-effective and versatile method for producing submicron fibers. Although this method is relatively simple, at the theoretical level the interactions between process parameters and their influence on the fiber morphology are not yet fully understood. In this paper, the aim was finding optimal electrospinning parameters in order to obtain the smallest fiber diameter by using Taguchi's methodology. The nanofibers produced by electrospinning a solution of Thermoplastic Polyurethane (TPU) in Dimethylformamide (DMF). Polymer concentration and process parameters were considered as the effective factors. Taguchi's L9 orthogonal design (4 parameters, 3 levels) was applied to the experiential design. Optimal electrospinning conditions were determined using the signal-to-noise (S/N) ratio with Minitab 17 software. The morphology of the nanofibers was studied by a Scanning Electron Microscope (SEM). Thereafter, a tensile tester machine was used to assess mechanical properties of nanofibrous scaffolds. The analysis of DoE experiments showed that TPU concentration was the most significant parameter. An optimum combination to reach smallest diameters was yielded at 12 wt% polymer concentration, 16 kV of the supply voltage, 0.1 ml/h feed rate and 15 cm tip-to-distance. An empirical model was extracted and verified using confirmation test. The average diameter of nanofibers at the optimum conditions was in the range of 242.10 to 257.92 nm at a confidence level 95% which was in close agreement with the predicted value by the Taguchi technique. Also, the mechanical properties increased with decreasing fibers diameter. This study demonstrated Taguchi method was successfully applied to the optimization of electrospinning conditions for TPU nanofibers and the presented scaffold can mimic the structure of Extracellular Matrix (ECM).

The effect of the spinning conditions on the structure of mesophase pitch-based carbon fibers by Taguchi method

Zhao Jiang,Ting Ouyang,Xiangdong Yao,Youqing Fei 한국탄소학회 2016 Carbon Letters Vol.19 No.-

Taguchi’s experimental design was employed in the melt spinning of molten mesophase pitch to produce carbon fibers. The textures of the obtained carbon fibers were radial with varied crack angles, as observed by scanning electron microscopy and polarized optical imaging. The diameter, crack angle, preferred orientation, and tensile modulus of the produced samples were examined to investigate the influence of four spinning variables. The relative importance of the variables has been emphasized for each characteristic. The results show that thicker carbon fiber can be obtained with a smaller entry angle, a higher spinning temperature, a reduced winding speed, and an increased extrusion pressure. The winding speed was found to be the most significant factor in relation to the fiber diameter. While it was observed that thicker carbon fiber generally shows improved preferred orientation, the most important variable affecting the preferred orientation was found to be the entry angle. As the entry angle decreased from 120° to 60°, the shear flow was enhanced to induce more ordered radial alignment of crystallite planes so as to obtain carbon fibers with a higher degree of preferred orientation. As a consequence, the crack angle was increased, and the tensile modulus was improved.

Multi-objective optimization of process parameters for the helical gear precision forging by using Taguchi method

Wei Feng,Lin Hua 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.6

Precision forging of the helical gear is a complex metal forming process under coupled effects with multi-factors. The various process parameters such as deformation temperature, punch velocity and friction conditions affect the forming process differently, thus the optimization design of process parameters is necessary to obtain a good product. In this paper, an optimization method for the helical gear precision forging is proposed based on the finite element method (FEM) and Taguchi method with multi-objective design. The maximum forging force and the die-fill quality are considered as the optimal objectives. The optimal parameters combination is obtained through S/N analysis and the analysis of variance (ANOVA). It is shown that, for helical gears precision forging, the most significant parameters affecting the maximum forging force and the die-fill quality are deformation temperature and friction coefficient. The verified experimental result agrees with the predictive value well, which demonstrates the effectiveness of the proposed optimization method.

다구찌 방법과 실험계획법을 이용한 농기계용 소음기의 최적화에 관한 연구

이규태,신광수 朝鮮大學校 機械技術硏究所 1998 機械技術硏究 Vol.1 No.1

본 연구에서는 배기계의 소음 조감을 위한 소음기의 성능향상에 대한 연구를 수행하였다. 기존의 파동방정식에 의한 전달 매트릭스법(transfer matrix method)과 유한요소법(FEM) 대신 다구찌 방법과 일부실시법을 이용하여 오버올 레벨을 최대로 하는 최적조건을 찾아내었다. 기존설계안을 바탕으로 성능에 영향을 미친다고 생각되는 각 부품의 길이와 반경등을 인자로 선정하였다. L18, L27 직교배열표를 사용하여 인자를 배치하였으며 1/3 일부실시법을 통하여 어떤 교호작용이 유의한지를 찾아내었다. 소음·진동제어연구실에서 개발한 LAEXS라는 시뮬레이터를 이용하여 시뮬레이션을 수행하였다. 이를 통하여 찾아낸 최적조건에서 기존의 설계안보다 오버올 레벨은 26.9 dB, SN비는 1.39dB 증가하는 효과를 가져왔다. In this study, we accomplished research of improving the muffler's capacity for reduction noise of exhaust system. Instead of using transfer matrix method by wave equation and finite element methods, we find optimal condition that maximizes overall level by using Taguchi methods and fractional factorial design. On the basis of existing design, we selected factors such as length and radius of each component that was thought to effect to capacity of muffler, factors are arranged by using L18, L27 table of orthogonal array, also, we found some significant interaction effects by using 1/3 fractional factorial design. For this simulation, we use the LAEXS which was developed in the laboratory of noise and vibration control. From the simulation results, compared with the existing design, overall level increased 26.9 dB and SN ratio increased 1.39 dB.

민감도 해석과 다꾸지 기법을 이용한 대형트럭 캡의 Front Structure 최적화에 관한 연구

류승훈(Seunghun Ryu),최균(Kyoon Choi) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

Recently, the size of Shock Absorber and air spring is enlarged to improve ride quality. Consequently, a location of front Cab mounting system is changed from under frame to front of dash board panel. In this paper, The goal is to improve strength and stiffness according to change of load point. For the optimization of design parameters in large-sized truck Cab system are used sensitivity analysis and Taguchi method which is one of the robust design methods. In order to obtain the best combination of each control factor, the dynamic and the norminal s-best type characteristic parameter method are used for the strength and stiffness output response. In this paper, eight control factors which are determinated according to sensitivity analysis are used for analysis; one with two levels and seven with three level combinations comprising the design of the L₁?(2¹X3?) orthogonal array. With this optimal design, The result of torsional test shows that strength is improved by 15% and the static stiffness increased by 30%.

다구찌 직교배열법을 이용한 포뮬러 레이스카 전륜 업라이트의 최적설계

장운근(Woon Geun Jang) 한국생산제조학회 2013 한국생산제조학회지 Vol.22 No.1

Formula race car is generally recognized as a vehicle which is optimally designed for on-road race track with the regulations of race host bodies. Especially, the uprights of suspension system decisively have effects on the performance of cornering and stability of race cars driving performance, which are very important factors in the design of race car. This paper is a study of optimal upright design of F1800 grade formula race car which are normally used in professional race circuit in Korea. To design optimally the front upright of F1800 formula race car, Taguchis orthogonal array, which is known for more useful method than full factorial design experimental method in cost and time, is used with CAE method such as FEM analysis. And the result of this paper shows that Taguchis orthogonal array employed for this optimal design is very useful for designing the front upright of race car by minimizing its weight as well as keeping its safety factor as enough as designer wants in the view of quality, cost and delivery at the early design step.

Gear hot forging process robust design based on finite element method

Chen Xuewen,정동원 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.9

During the hot forging process, the shaping property and forging quality will fluctuate because of die wear, manufacturing tolerance, dimensional variation caused by temperature and the different friction conditions, etc. In order to control this variation in performance and to optimize the process parameters, a robust design method is proposed in this paper, based on the finite element method for the hot forging process. During the robust design process, the Taguchi method is the basic robust theory. The finite element analysis is incorporated in order to simulate the hot forging process. In addition, in order to calculate the objective function value, an orthogonal design method is selected to arrange experiments and collect sample points. The ANOVA method is employed to analyze the relationships of the design parameters and design objectives and to find the best parameters. Finally, a case study for the gear hot forging process is conducted. With the objective to reduce the forging force and its variation, the robust design mathematical model is established. The optimal design parameters obtained from this study indicate that the forging force has been reduced and its variation has been controlled.

Optimization of the preparation of activated carbon from palm kernel shell for methane adsorption using Taguchi orthogonal array design

Syed Shatir Asghrar Syed-Hassan,Mohd Saufi Md Zaini 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.8

The preparation of activated carbon from palm kernel shell for methane adsorption was studied. Taguchi orthogonal array design was employed to optimize the preparation of activated carbon. The statistical results show that the optimized conditions are the impregnation ratio of 0.55, the activation temperature of 900 oC and the activation time of 150min. The impregnation ratio has the most influence on methane adsorption based on S/N ratio analysis. The mathematical model was developed using regression analysis as a function of independent variables. The results of experiment using optimum conditions fall within the predicted value obtained from the developed model. Activated carbon prepared at optimum conditions which have the highest BET surface area of 1,548.0m2/g and the total pore volume of 1.0 cm3/g recorded the highest methane uptake compared to other conditions. The equilibrium data of the adsorption characteristic fitted favourably to the Freundlich isotherm.

AL 소재의 항공기 날개 가공 시 절삭 조건이 형상 오차에 미치는 영향

염경섭(Kyoung-Seob Yeom),이홍주(Hong-Gu Lee),강재관(Jae-Gwan Kang) 한국기계가공학회 2006 한국기계가공학회 춘추계학술대회 논문집 Vol.2006 No.-

A spar is a part to hold the aircraft wing, and takes very important role in maintaining the aircraft safety during landing and taking off. Spar uses AL material and is manufactured in the 5-axis machining center, but high cutting temperature makes the large size spar distort significantly after machining. In this paper, we tried to find the main factors which influence on the distortion during machining the aircraft spar. L8(27) orthogonal array table was employed for experiment design and the famous Taguchi method was used for the statistical analysis of experiment data.