• Elastomers and Composites
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• 제47권4호
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• pp.347-354
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• 2012

사출성형에 CAE (Computer Aided Engineering)을 적용함으로써 사출 성형품 설계와 공정조절에 큰 도움이 된다. 또한 성형의 효율성을 최대화하고 개발기간의 단축, 그리고 고품질 제품을 확보하는데 도움이 크다. 특히 신제품 개발에 대한 설계방안을 제시하고 실패율을 감소시킬 수 있다. 현재 사출성형의 CAE는 2D는 물론 3D도 해석이 가능한데 이 두 가지 방식은 약간의 차이를 가짐에도 불구하고 해석 상 차이에 관한 비교 및 일반적인 가이드라인이 정해져 있지 않다. 본 연구에서는 제품의 두께, 형상 그리고 유한요소 수에 따른 2차원 해석과 3차원 해석을 비교하였다. 그리고 실험을 통해 얻은 캐비티 내의 압력과 온도를 해석결과와 비교하였다. 본 연구를 통하여 사출성형의 2D해석과 3D해석에 대한 가이드라인을 제시하고자 하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.578-583
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• 2007

Many papers have studied computer-aided simulations of elastic bodies undergoing large deflections and large deformations. But there have been few attempts to validate their numerical formulations used in these studies. The main aim of this paper is to validate the absolute nodal coordinate formulation (ANCF) by comparing the results to experimental measurements on beams. Physical experiments with a high-speed camera were carried out to capture the large displacement of the beam and to verify the results of computer simulations. To consider the damping forces, the Rayleigh's damping and quadratic damping are employed and compared to the experimental results, respectively. Numerical results obtained from computer simulations were compared with the results from the physical experiments according to the $1^{st}$ mode and the $2^{nd}$ mode of the beam, respectively.

• Advances in aircraft and spacecraft science
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• 제2권4호
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• pp.445-467
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• 2015

The paper presents some details of the CFD modeling of a novel design where jet ignition devices replace the traditional spark plugs for a faster and more complete combustion. The numerical simulations show how the pre-chamber jet ignition in a Wankel engine differs from reciprocating piston engine applications. The jets issuing from the jet ignition pre-chamber have many different speeds in the different directions as the pressure build-up at the trailing edge of the rotating chamber makes extremely fast the ignition of the chamber mixture in the direction of rotation. Conversely it prevents the jet ignition in the opposite direction. Careful positioning along the periphery and design of the connecting pipes and the prechamber volume with the help of CFD simulations permits to achieve extremely fast and complete combustion as impossible with spark plugs. The paper proposes results of CFD simulations of the combustion evolution within a jet ignited Wankel engine rotor, detailing challenges and opportunities of the application, as well as a first assessment of the impact the faster and more complete combustion permitted by jet ignition may have on the performances of Wankel engines for unmanned aerial vehicles applications.

• 소성∙가공
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• 제15권5호
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• pp.347-353
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• 2006

The delivery system such as sprue, runner and gate is a waste of resin in injection molding operation. In this study the reduction of runner size has been investigated using injection molding CAE softwares, Moldflow and Moldex3D, and commercial CFD Softwares, Fluent and Polyflow. To verify the computational results experiment was performed. There were three considerations in deciding optimal runner size in this study: minimum pressure at the gate that makes resin fully filled in the cavity, minimum runner size that compensates shrinkage of resin in the cavity, and frozen layer thickness formed in the runner during injection. Through the computer simulations the optimal runner size that satisfies those three considerations has been decided. Although the computational results among the softwares were slightly different, it was enough to predict the optimal runner size. The previous runner diameter was 8 mm and predicted optimal size was 5 mm. This was verified by injection molding experiment. Thus, the way of CAE application in deciding optimal runner size adapted in this study would be appropriated.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.363-366
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• 2006

The delivery system such as sprue, runner and gate is a waste of resin in injection molding operation. In this study the reduction of runner size has been investigated using injection molding CAE softwares, Moldflow and Moldex, and commercial CFD Softwares, Fluent and Polyflow. To verify the computational results experiment was performed. There were three considerations in deciding optimal runner size in this study: minimum pressure at the gate that makes resin fully filled in the cavity, minimum runner size that compensates shrinkage of resin in the cavity, and frozen layer thickness formed in the runner during injection. Through the computer simulations the optimal runner size that satisfies those three considerations has been decided. Although the computational results among the softwares were slightly different, it was enough to predict, the optimal runner size. The previous runner diameter was 8 mm and predicted optimal size was 5 mm. This was verified by injection molding experiment. Thus, the way of CAE application in deciding optimal runner size adapted in this study would be appropriated.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.2-61
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• 2006

• 한국자동차공학회논문집
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• 제17권1호
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• pp.114-119
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• 2009

The authors have investigated the NVH problems of drive system in full vehicle test. However it is difficult to define the NVH problems of driveline system. Since it is hard to measure the rotating part and it is vague that only the drive system induces the NVH problem. Vibration in a driveline is presented in this paper. In the experiment, the rear sub-frame and propeller shafts and axle were composed and mounted with rubber each other. For applying the vibration input instead of the torsional vibration effect of an engine, the shaker was taken. In particular, torsional vibration due to fluctuating forced vibration excitation across the joint between driveline and rear sub-frame was carefully examined. Accordingly, the joint response was checked from experiments and the FE-simulation using FRF (frequency response function) analysis was performed. All test results were signal processed and validated against numerical simulations. In present study, the new test bench for measuring the vibration signal and simulating the vehicle chassis system was proposed. The modal value and the mode shape of components were analyzed using the CAE model to identify the important components affecting driveline noise and vibration. It could be reached that the simplified test bench could be well established and be used for design guide and development of the vehicle chassis components.

• 한국자동차공학회논문집
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• 제17권5호
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• pp.16-25
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• 2009

Testing engine performance using an engine dynamometer requires high technical researchers and many facilities. Nowadays, different variables of CAE program are used for identifying the engine performance instead of engine dynamometer test. This is more convenience, as it does not necessitate an abundance of engine dynamometer experiments and, in addition, produces better results. However, CAE programs also contain various variables which can affect engine performance. Those are coupled with each other, thus making it difficult to determine the effectiveness of different variables on engines. DoE (Design of Experiments) methodology is an efficient way to verify the magnitude of effectiveness on engine performance as well as making responses to be optimized at once without trial & error. This study used data from WAVE simulations, which modeled the DOHC SI engine with in-line 4 cylinders at 1500, 3000 and 4500rpm. DoE methodology is designed properly to determine the effectiveness of five variables on power, BSFC, and volumetric efficiency, as well as to find the optimal response conditions at each rpm through a minimized number of experiments. After finishing DoE process, all the results are examined concerning the reliability of test through a verification experiment.

• 한국염색가공학회지
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• 제34권4호
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• pp.250-260
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• 2022

In this research, a high-elasticity acrylic emulsion binder with core-shell polymerization and self-crosslinking system is mixed with a flame-retardant water-dispersed polyurethane (PUD) binder. In addition, finite element analysis was conducted through virtual engineering software ANSYS by applying three representative nonlinear material models. The most suitable nonlinear material model was selected after the relative comparison between the actual experimental values and the predicted values of the properties derived from simulations. The selected nonlinear material model is intended to be used as a nonlinear material model for computational simulation analysis that simulates the experimental environment of the vibration test (ASTM E1399) and the actual fire safety test (ASTM E1966). When the mass fraction of thermally expandable graphite was 0.7%, the thermal and physical properties were the best. Among the nonlinear material models, the simulation result of the Ogden model showed the closest value to the actual result.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 The 8th Asian Symposium on Precision Forging ASPF
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• pp.80-85
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• 2003

This research represents enhancement of forgeability of SNCM522H steel. Output Shaft (OP Shaft) has been used as a subject for the study. OP Shaft is used as component of power train for automobiles. To develop I pass cold forging process instead of existing 2 pass process for OP Shaft, studies in terms of process design and heat treatment were performed. To verify the new process, CAE simulations were performed. And hardness test, microstructural analysis and tensile tests after heat treatment were carried out to evaluate the validity of proposed heat treatment cycle. The 2 pass forging process could be reduced as 1 pass process through improvement of process and heat treatment cycle.