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Incremental Sheet Metal Forming : a rapid prototyping process to make an automobile body modeling
Duc-Toan Nguyen,Nam-Kyu Kim,Tae-Hoon Choi,Young-Suk Kim 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
In order to make an automobile body modeling, Incremental sheets forming is introduced as a rapid prototype process. Numerical modeling of the process is firstly used to predict the deformation of the sheet metal to avoid failure during the forming process. Automobile CAD model is then designed, and segmented into several parts in order to accommodate with working space of CNC machine and formability of sheet metal . After that, CAM software is used to generate tool-path for making wooden-dies and all small parts. Finally, welding process is applied to join all division parts which were cut by laser cutting after incremental sheet forming process.
Duc-Toan Nguyen,김영석 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.
In order to obtain a final sound product by the incremental sheet forming (ISF) process for complex shape using cold rolled steel material, the limit curve based on the maximum wall angle versus maximum deformed height was established utilizing finite element method (FEM) simulations for several square shapes with various wall angles. The forming limit diagram (FLD) obtained from modified maximum force criterion (MMFC) was first used to predict ductile fracture of ISF simulation test and shown the inaccuracy when comparing with corresponding experimental results. The FLC at fracture (FLCF) curve regarding to tool dimension effects was then proposed, inputted to FEM simulation and approved in good agreement with experiment results. After that wall angle of square shapes was changed to verify its effect on fracture height of the square shapes and obtain the forming limit curve. Finally, wall angles with corresponding maximum deformed height of complex shapes were put into the obtained forming limit to investigate “fail” or “safe” shapes and validated by corresponding experiments.
Duc Ba Nguyen,Van Toan Nguyen,허일정,목영선 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.72 No.-
The hydrocarbon selective catalytic reduction (HC-SCR) of nitrogen oxides (NOx) over Ag/α–Al2O3 withtemperaturefluctuation in the range of 150–350 C was investigated in a packed-bed dielectric barrierdischarge plasma reactor. The results revealed that the HC-SCR coupled with plasma maintained highNOx reduction efficiency around 74% regardless of the temperature variations in the range from 150 to350 C (10–40 C/min). In comparison, the NOx reduction efficiency of the HC-SCR-alone process wasvaried from 37.6 to 63.4%, depending on the reaction temperaturefluctuations. Consequently, the strongtemperature dependence of catalytic activity can be resolved by integrating plasma and catalysis.
( Nguyen Van Toan ),( Nguyen Duc Ba ),목영선 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
At low operating temperatures (≤ 300 °C), the NOx removal efficiency in exhaust gases is generally low, due to plasma-catalyst is mainly oxidize NO to NO<sub>2</sub>. In this work, a dielectric barrier discharge (DBD) reactor coupled with the ZSM-5-supported bimetallic catalysts (Co-ZSM-5 and Ag-ZSM-5) was investigated to improve NO<sub>x</sub> reduction efficiency under low operation temperature condition. Aiming at finding out suitable catalyst materials and understanding the interaction between plasma and catalyst in NOx reduction process. The effect of the reaction temperature and the energy density on the NO<sub>x</sub> reduction was examined and discussed. The result showed that the presence of the elements (Co and Ag) in the catalysts significantly improved the adsorption of NO<sub>2</sub> at low temperatures, so that the performance of catalytic NO<sub>x</sub> reduction could be kept high over a wide temperature range.
( Nguyen Duc Ba ),( Nguyen Van Toan ),목영선 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0
Ag/Al<sub>2</sub>O<sub>3</sub> catalyst with hydrocarbons as a reduction agent is potential for selective catalyst reduction of NOx at a temperature above 300°C. However, NOx efficiency removal decreased sharply at an early state or low temperature, owing to the low activity of hydrocarbon reducing agent at low-temperatures (≤ 250°C). In order to expended temperature window, a combination of the catalyst with atmospheric-pressure plasma has been proposed, since plasma-catalyst enhanced partially oxidize hydrocarbons at low temperature and these hydrocarbon derivatives are more activity for NOx removal. In this work, several hydrocarbons such as C<sub>2</sub>H<sub>4</sub>, C<sub>3</sub>H<sub>8</sub>, and C<sub>7</sub>H<sub>16</sub> have been proposed as a reducing agent for the process. The effects will consider in terms of NOx efficiency removal, energy efficiency, and hydrocarbon consumption.
Improving formability of tube bending for a copper material using finite element simulation
Duc-Toan Nguyen,Dinh-Thanh Nguyen,김영석 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10
Bending tubes are key products in many industries. The geometric parameters of the bending process are considered according to Taguchi’sorthogonal array and then coupled with finite element simulation to predict and improve the formability of the tube bendingprocess for copper JIS25A material. Three parameters, namely, mandrel diameter, distance between mandrel rings, and distance from thetip of the mandrel bar to the center of the base die, are selected to study their effects on the quality of the bending process. The varianceanalysis shows that the effect distribution of each parameter to bending quality is determined, and optimal conditions are adopted to conductexperiments.
Flow Stress Equations of Ti-6Al-4V Titanium Alloy Sheet at Elevated Temperatures
Duc-Toan Nguyen,김영석,정동원 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.
In this study, to achieve constitutive equations of Ti-6Al-4V alloy sheet, uni-axial tensile tests of Ti-6Al-4V alloy sheet with thickness of 1.0mm were performed at elevated temperature of 400oC ~ 700oC. Equations of stress-strain curves are established for Ti-6Al-4V alloy sheet at elevated temperatures describing both work-hardening and softening stage of Ti-6Al-4V alloy sheet. Least square fitting method is used to determine material parameters. The parameters of fitting curves are utilized to determine them as a function of temperature using polynomial models. New mathematical models are used to calculate and predict the stress-strain curves at elevated temperatures. The calculated flow stress curves are in good agreement with experimental data and shown better than that of previous equation.