http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : 뚜안(D. T. Nguyen) (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
-
D.T. Nguyen(누엔 늑 뚜안),C.H. Suh(서창희),S.H. Yang(양승한),Y.S. Kim(김영석) 한국소성가공학회 2010 한국소성가공학회 학술대회 논문집 Vol.2010 No.10
In order to predict correctly stress-strain curve for tensile test in elevated and quenching temperatures, a modification of Johnson-Cook (J-C) model and a new method to determine (J-C) material parameters are proposed. MAT LAB tool is used to determine material parameters by fitting curve follow Ludwick and Voce"s hardening law at various elevated temperatures. Those hardening law parameters are then utilized to determine modified (J-C) model material parameters. The modified (J-C) model shows the better prediction comparing with conventional one. FEM tensile test simulation based on isotropic hardening model for metal sheet at elevated temperatures was carried out via a user-material subroutine, using explicit finite element code. The simulation results at elevated temperatures were firstly presented and compared with measurements. Quenching temperatures at all elements was then calculated when considering the modified (J-C) model and coded to VUMAT subroutine for tensile test simulation. The modified (J-C) model showed the good agreement between simulation results and corresponding experiments.
-
Incremental Sheet Forming of Complex Geometry Shape and Its Optimization Using FEM Analysis
D. T. Nguyen(누엔 늑 뚜안),J. G. Park(박진기),H. J. Lee(이혜진),Y. S. Kim(김영석) 한국소성가공학회 2009 한국소성가공학회 학술대회 논문집 Vol.2009 No.5
In order to optimize the press formability of incremental sheet forming for complex shape (e.g human face), a combination of both CAM and FEM simulation, is implemented and evaluated from the histories of stress and strain value by means of finite element analysis. Here, the results, using ABAQUS/Explicit finite element code, are compared with fracture limit curve (FLC) in order to predict and optimize the press formability by changing parameters of tool radius and tool down-step according to the orthogonal array of Taguchi’s method. Firstly, The CAM simulation is used to create cutter location data(CL data). This data are then calculated, modified and exported to the input file format required by ABAQUS through using MATLAB programming. The FEM results are implemented for negative incremental sheet forming and then investigate by experiment.
-
누엔 늑 뚜안(D. T. Nguyen),박진기(J. G. Park),김영석(Y. S. Kim) 한국소성가공학회 2009 마그네슘 심포지엄 Vol.2009 No.11
In order to predict the ductile fracture of rotational incremental forming for magnesium alloy sheet, a combination of kinematic and isotropic hardening law is implemented and evaluated from the histories of ductile fracture value (Ⅰ) by means of finite element analysis. Here, the criterion for a ductile fracture, as developed by OYANE, [J. Mech. Work. Tech. 4 (1980), pp. 65-81], is carried out via a user material, using finite element code. To simulate the effect of the large amount of heat generation at elements in the contact area due to friction energy of the rotational tool-specimen interface on equivalent stress-strain evolution in incremental forming, Johnson-Cook model was applied and also compared with equivalent stress-strain curves obtained by tensile test at elevated temperatures. The (FE) simulation results of ductile fracture was then compared with the experimental results of 80 ㎜ × 80㎜ × 25 ㎜ square shape with 45°, 60°, and 80 ㎜ × 80㎜ × 20 ㎜ square shape with 70° wall angles. The trend of (FE) simulation results were quite good agreement with experiment results. Finally, the forming limit curve at fracture (FLCF) were predicted using (FE) simulation results.
-
아루무감(Arumugam S),홍성훈(S. H. Hong),뚜안(D. T. Nguyen),마니반난(Manivannan R),김영석(Y. S. Kim) 한국소성가공학회 2010 한국소성가공학회 학술대회 논문집 Vol.2010 No.5
At presence the industrial practice demands a reliable determination of forming limits which assures the prediction of properly selecting the forming process in a digital environment. Therefore, technological limits defined with the forming limit diagrams (FLDs) have to be known. The experimental evaluation of FLDs for sheet metal is time consuming and demands expensive equipment. Hot press forming (HPF) is an advanced sheet metal forming methodology which can able to produce high strength final product by forming the part with high temperature and also cooling the part rapidly inside dies, it’s an one of the most successful forming process which can produce a component with complex geometric shape, high strength and minimum spring back. For conventional sheet metal forming processes the forming limit diagram (FLD) is primarily applied as failure criterion in the automotive industry regarding a FE-based process design. This works deals with the prediction of formability of sheet metal during the hot press forming. In order to predict the FLD at high temperature, we used Marciniak-Kuczynski flat punch for equi-biaxial and round punch for uniaxial and plane strain for In-plane deformation test. However, thermo-mechanical coupled simulation carried out by using DEFORM-3D for forming and predicting the failure by using Normalized Cockcroft-Latham failure criterion model. By applying the above failure criteria in DEFORM-3D FLD simulation, we need to determine the critical damage values (C?) calculated from out of plane deformation test for uniaxial and plane strain experiments carried out at 25℃ (RT), 500℃ and 700℃. In addition, the formability of the simulation results in a hot press formed part is compared with the experimental ones to confirm the validity of the proposed simulations.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
