• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 추계학술대회 논문집
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• pp.491-496
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• 2010

The direct design modification of problematic component is disallowed in order to sacrifice other major factors such as a stability or a major performance. So, the best design policy is to risvise the immature structural medchanism under the minimal design change as soon as possible. For this paper presents a new design sensitivity analysis based on transmissibility rtio (TR) of response acceleration to find a proper candidate for the minimal design modification. The new sensitivity analysis is based on the fact that the sensitivity of TR over a small design change is inversly proportinal to the magnitude of TR. The theory of proposed design sensitivity analysis is simulated with the variance of TR over a dynamic change. Then, new methodology is appplied for a linear elastic specimen to detect the most sensitive node over a design change using measured accleration data during uni-axial vibration test, The physical verification of the sensitivity method is conducted on the CAE model of a linear elastic specimen by adding concentration mass and the vibration fatigue of the simple specimen is analyzed to estimate the relationship between fatigue behaviors and sensitivity consequences.

• 한국안전학회지
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• 제17권3호
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• pp.36-42
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• 2002

Structural integrity of either a passenger car or a light truck is one of the basic requirements for a full vehicle engineering and development program. The results of the vehicle product performance are measured in terms of ride and handling, durability, noise/vibration/harshness(NVH), crashworthiness and occupant safety. The level of performance of a vehicle directly affects the marketability, profitability and, most importantly, the future of the automobile manufacturer. In this study, we used the virtual proving ground(VPG) approach for obtaining the dynamic characteristics. VPG approach uses a nonlinear, dynamic, finite element code(LS-DYNA3D) which expands the application boundary outside the classic linear, antic assumptions. VPG approach also uses realistic boundary conditions of tire/road surface interactions. To verify the predicted dynamic results, a single lane change test has been performed. The prediction results were compared with the experimental test results, and the feasibility of the integrated CAE analysis methodology was verified.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2009년도 추계학술발표논문집
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• pp.885-888
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• 2009

자동차용 Alloy Wheel은 차량의 수직하중이나 가로 방향 하중, 구동, 제동토크 등 주행 시에 발생하는 여러 형태의 응력을 받으면서 사용되므로 이러한 응력을 견딜 수 있는 강성은 물론 차량 부품으로서의 요구 수명도 만족하여야 한다. 알루미늄 휠은 개발 후 규격에 준하는 내구성 평가를 위하여 반경 방향 부하 내구시험과 굽힘모멘트 내구시험과 주행 중 요철이나 벽돌 등에 의한 노면으로부터 갑작스런 하중에 대한 내충격성 평가를 위한 충격시험이 실행되고 있다. 이러한 시험은 많은 시간이 소요되고 있으며, 또한 시험 중 불합격 판정이 날 경우 또다시 처음의 공정을 모두 거쳐 다시 시험을 하게 된다. 3 Piece와 같은 알루미늄 휠은 여러 공정에 의한 생산되어지기 때문에 많은 시간적, 물질적 손실이 일어나고 있다. 따라서 자동차용 알루미늄 휠의 요구조건을 충분히 만족시키며 소비자의 요구에 맞는 품질과 시간을 충족시켜 기업경쟁력 확보는 물론 원가절감에 의한 기업 경쟁력 향상을 위하여 설계 단계서부터 시험조건을 고려한 내구성 해석에 의한 알루미늄 휠의 시험횟수를 단축하고자 한다. 본 논문에서는 3 Piece 알루미늄 휠의 축(shaft)하중에 의한 내구성 평가에 대하여 CAE시스템을 이용하여 보다 빠르고 정확한 결과를 산출함으로서 설계시간의 단축은 물론 다양한 형상의 제품들을 설계단계에서부터 생산에 이르기까지의 해석활용법을 수립하고자 하였다.

• 한국정밀공학회지
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• 제28권3호
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• pp.349-356
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• 2011

This paper replaces a conventional austenitic stainless steel sheet to a ferritic stainless steel for the cost reduction of a pulsator cover of a washing machine. However, ferritic stainless steel has poor formability in comparison with austenitic one. The low formability of ferritic steel results in problems during stamping such as fracture, wrinkling, shape inaccuracy and so on. Design modification of the stamping tool is carried out with the aid of the finite element analysis for multistage stamping process of the pulsator cover. The simulation results show that fracture occurs on top of the product while wrinkles are generated by the excess metal near the wing part. Modification of the initial stamping die is performed to improve metal flow and to eliminate problems during the stamping process. Simulation with the modified design fully demonstrates that safe forming is possible without inferiorities.

• 한국소음진동공학회논문집
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• 제16권9호
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• pp.926-936
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• 2006

In this study, structural vibration analyses of a smart unmanned aerial vehicle (UAV) have been conducted considering dynamic loads generated by rotating rotor and wakes. The present UAV (TR-S5-03) finite element model is constructed as a full three-dimensional configuration with different fuel conditions and tilting angles for helicopter, transition and airplane flight modes. Practical computational procedure for modal transient response analysis (MTRA) is established using general purpose finite element method (FEM) and computational fluid dynamics (CFD) technique. The dynamic loads generated by rotating blades in the transient and forward flight conditions are calculated by unsteady CFD technique with sliding mesh concept. As the results of present study, transient structural displacements and accelerations are presented in detail. In addition, vibration characteristics of structural parts and installed equipments are investigated for different fuel conditions and tilting angles.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.367-375
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• 2006

In this study, structural vibration analyses of a smart unmanned aerial vehicle (UAV) have been conducted considering dynamic loads generated by rotating rotor and wakes. The present UAV (TR-S5-03) finite element model is constructed as a full three-dimensional configuration with different fuel conditions and tilting angles for helicopter, transition and airplane flight modes. Practical computational procedure for modal transient response analysis (MTRA) is established. using general purpose finite element method (FEM) and computational fluid dynamics (CFD) technique. The dynamic loads generated by rotating blades in the transient and forward flight conditions are calculated by unsteady CFD technique with sliding mesh concept. As the results of present study, transient structural displacements and accelerations are presented in detail. In addition, vibration characteristics of structural parts and installed equipments are investigated for different fuel conditions and tilting angles.

• 한국자동차공학회논문집
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• 제19권5호
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• pp.113-117
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• 2011

The frame for automotive assembly can be deformed and remained on the residual stress due to high temperature thermal attacks when in welding. The frame deformation can be made to problems when in assembly with body and the residual stress can affect the negative effect on durability performance of the automobile. In order to analyze the frame deformation, the simplified test frame which had the similar shape (form) of the real automotive frame was fabricated. The contactless optical 3D scanner was used for the shape difference measurement of the frame between before and after the welding. The FE-model of the test frame was composed and the heat transfer and thermal stress simulation were performed. The simulated results were compared with the measured results for the reference of the frame design. The deformation shape of the frame by simulation was in good agreement with that by the experimental measurement.

• 드라이브 ㆍ 컨트롤
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• 제11권4호
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• pp.46-52
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• 2014

This study suggests a small-sized screw decanter specialized for dredging sites. Generally, conventional screw decanters are composed of a cylinder and a cone. However, the suggested screw decanter simply has a cone based on a cone-type bowl structure. In this research, a commercial analysis tool is used to establish an optimal design for the bowl and the screw conveyor. Moreover, the base frame, where the main bearings that support the spindle of the bowl and the screw conveyor are installed, is optimally designed considering the weight of the rotating body and the deflection caused by the high centrifugal force. Furthermore, the natural frequency range of the spinning body, the bowl and the screw conveyor, is applied to this base frame; it is designed not to correspond to the resonance frequency range and achieves stability as a result. This study suggests an optimal design for the rotating body and the base frame of a screw decanter considering its vibration characteristics. Such a design will prevent overuse of materials and help to reduce the weight and volume-and the price-of a screw decanter.

• 한국자동차공학회논문집
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• 제10권5호
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• pp.168-173
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• 2002

The durability test, along with the crashworthiness test, requires the most time and expense in the vehicle development process. The durability design using CAE tools reduces the time required for both the durability test and actual vehicle production. Existing dynamic stress analyses designed fir the analysis of vehicle fatigue mainly calculate the dynamic stress history and fatigue after performing dynamic analysis and stress analysis with relevant software applications and then superpositioning the dynamic load history and stress influence coefficient at each joint. This approach is a complex process, taking into account the flexibility of the parts. It is, however, incapable of giving accurate consideration to the contacts between components, the non-linearity of materials, and tire-road surface interactions. This approach also requires that the analysts have an expertise in software applications of various kinds or an expert in each area must perform the analysis. This requires as a great deal of manpower and time. In order to complement the existing approaches for dynamic stress analysis, this study aims at the following: (1) to suggest the simple and accurate analysis technique which is capable of producing all the possible necessary results; (2) to reduce dramatically the time and manpower needed to construct a model designed to analyze dynamics, quasi-static stress, and fatigue; and (3) to enable an accurate analysis of fatigue by improving the accuracy of dynamic stress. we verify the presented analysis method through durability evaluation of the knuckle of passenger car.

• 실천공학교육논문지
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• 제10권2호
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• pp.125-129
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• 2018

이 논문은 LTP 퍼니스의 최적화 된 내부 유동과 온도의 균일성에 대한 수치 해석에 관한 것이다. 반도체 제조 공정에서 실리콘 웨이퍼를 어닐링하기 위한 기능을 수행한다. 특히 챔버 내부의 최고 온도를 약 $400^{\circ}C$의 고온으로 유지하여 웨이퍼를 보강한다. 공정이 고온에서 완료되면 열 교환기를 통해 온도를 낮추고 이를 수행하기 위한 작업이 반복된다. 이 논문에서 최종적인 목표는 LTPS 퍼니스의 유동 해석을 통해 챔버의 단열 공급과 배기 구조의 최적 설계를 도출하는 것과 교육과정 개발을 위한 사례 발굴에 있다.