• 한국자동차공학회논문집
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• 제4권6호
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• pp.27-38
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• 1996

A two-dimensional FEM program, which considers bending effects in the membrane fromulation, was developed under plane strain assumption for analyzing forming processes of an arbitrarily shaped draw-die of automotive panels. For the evaluation of bending effects with membrane elements, the bending equivalent forces and stiffnesses are calculated from the bending moment computed using the changes in curvature of the formed shape of two membrane ones. The curves depicted with 3 nodes are described by a circle, a quadratic equation, and a cubic equation, respectively, and in the simulation of the stretch/draw sections of an automotive inner panel, three different description results are compared each other. Also, the bending results are compared with membrane results and measurements in order to verify the validity of the developed program.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1424-1428
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• 2005

This paper describes a dedicated three-dimensional CAD system for design of drawing dies for automotive body panels. Since solid die models are useful not only for simulations for design verification, but also for NC tool path generation to machine dies and their Styrofoam patterns, 3-D CAD systems have been introduced in the tooling shop of automotive manufacturers. However, the work to build solid models requires a lot of time and effort if the designer uses only the general modeling capabilities of commercial 3-D CAD systems. To solve this problem, we customized a 3-D CAD system for the drawing die design. The system provides not only 3-D design capabilities, but also standard part libraries to enhance design productivity. By introducing this system, the drawing dies can be designed more rapidly in the 3-D space, and their solid data can be directly transferred to CAM tools for NC tool path generation and simulation tools for virtual manufacturing

• 한국생산제조학회지
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• 제19권2호
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• pp.260-266
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• 2010

Today's consumers are looking for emotional design which can fulfill their own potential desire. Emotion varies according to individual circumstance, age, sex, culture, education, profession and so on. Automotive instrument panel design is the most important part of interior design, because it affects the impression of interior design and has the equipments for safety, entertainment and various information. Thus, this study was performed to apply emotional design to automotive instrument panel which is the most important part of automotive interior, and find the best bonding conditions to build instrument panel efficiently by comparing mechanical properties in thermoplastic resin of polyethylene (PE) adhesion. Satisfactory adhesion was executed in ultrasonic welding for the same materials of PE. The best welding conditions were found to be welding time of I second, welding pressure of 250 kPA for PE-PE welding. Dissimilar materials were adhered when adhesion and ultrasonic welding were performed at the same time.

• 한국자동차공학회논문집
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• 제10권4호
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• pp.141-148
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• 2002

Repair were made for front pillar, center pillar and side-step panel for lightweight vehicles with head-on and 40% off-set collision of 15 km/h in a RCAR standard. The salt dilution was sprayed and the compression tests were performed for vehicles with and without anti-corrosional treatment after repair. After 764 hours of salt-dilt sprayed test without using anti-corrosion, the mean penetration depth fur corrosion was shown to be 58% of the thickness. The resulyed decrease in bending stiffness by 10∼20% can cause reduction of the residual life and crash-absorption capability for damaged vehicles. The corrosoin safety tests showed that the anti-corrosional treatment should be made to improve the safety characteristics for a or damaged car.

• 한국산학기술학회논문지
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• 제18권3호
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• pp.72-77
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• 2017

본 논문은 자동차 프레스 절단 금형의 설계 자동화를 위한 설계 지원 툴 개발에 관한 연구을 다룬다. 현업에서 진행하는 자동차 패널 절단 공정 금형설계 프로세스를 분석하고 패턴을 가지는 반복 작업들을 그룹화 하여 자동화 모듈을 개발하였다. 제안하는 시스템은 절단금형 스틸파트를 자동 생성하는 템플릿 모델과 자동 생성된 절단금형 스틸파트를 자동 배치하는 UI 기능의 두 가지 모듈로 구성 하였다. 템플릿 모델은 트림스틸 설계에 활용되는 유형들을 고려하여 4가지 종류로 개발하였으며, 자동생성시 오류발생을 제로화 하기 위해 벡터 내적과 외적을 활용하여 설계기준이 되는 점, 선, 곡선, 면, 곡면의 방향을 체크 하고 바로잡는 방향성 제어 관계식 룰을 구현 하였다. 개발한 시스템을 대표 상용 CAD시스템 중 하나인 CATIA V5의 확장 메뉴형태로 탑재하기 위하여 CATIA Knowledgeware, CATIA SDK, Visual C++를 사용하여 개발하였다. 제안하는 시스템을 다양한 자동차 외관 패널에 적용한 결과 전통적인 방법에 비해 약 74%의 시간감축 효과를 얻을 수 있었다.

• 응용통계연구
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• 제34권5호
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• pp.697-710
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• 2021

상대오차를 이용한 예측법은 상대오차(혹은 퍼센트오차)가 중요시되는 분야, 특히 계량경제학이나 소프트웨어 엔지니어링, 또는 정부기관 공식통계 부분에서 기존 예측방법 외에 선호되는 예측방법이다. 그 동안 상대오차를 이용한 예측법은 선형 혹은 비선형 회귀분석 뿐 아니라, 커널회귀를 이용한 비모수 회귀모형, 그리고 정상시계열분석에 이르기까지 그 범위가 확장되어 왔다. 그러나, 지금까지의 분석은 고정효과(fixed effect)만을 고려한 것이어서 임의효과(random effect)에 관한 상대오차 예측법에 대한 확장이 필요하였다. 본 논문의 목적은 상대오차예측법을 일반화선형혼합모형(GLMM)에 속한 감마회귀(gamma regression), 로그정규회귀(lognormal regression), 그리고 역가우스회귀(inverse gaussian regression)의 패널자료(panel data)에 적용시키는데 있다. 이를 위해 실제 자동차 보험회사의 손해액 자료를 사용하였고, 최량예측량과 최량상대오차예측량을 각각 적용-비교해 보았다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.164-167
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• 2004

The draw, trim, flange, and cam forming processes of automotive fender panel are simulated, focused on the springbacks. Simulation results are compared with field try-out. In order to compensate the differences between simulation and try-out, the draw bead shapes in the simulation are modified and the accuracy of the simulation is improved by comparing blank draw-in amounts. The spring-backs after formings are also found in the simulation. Finally, the simulation procedures for analyzing the springbacks in all stamping processes are established.

• 대한기계학회논문집A
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• 제33권7호
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• pp.700-705
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• 2009

In order to enhance the dynamic stiffness of automotive panel, effect of bead and curved surface was investigated. Modal test was performed for principle specimens which have various kinds of beads, holes and curved surfaces. Test was also performed for conventional dash panel assembly and rear floor panel assembly and curved shaped ones. Results showed that curved shape increased the natural frequency of automotive panel more effectively than the bead. Finite element analysis was also performed and yielded good match with the test results.

• 풍력에너지저널
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• 제4권2호
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• pp.55-60
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• 2013

The mathematical implementation for inverse airfoil design of wind turbines is presented using vortex panel method based on assumptions of the two-dimensional incompressible potential flow. The vortex panel method employs linear distribution of the vortex strength to obtain the well converged solution. Stream function is adopted to get the basic formula for the inverse airfoil design, and a symmetric seed airfoil is given for initial data of the iteration approach. The final airfoil shape has been compared with the original airfoil shape for validation of the mathematical procedure.

• Composites Research
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• 제32권2호
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• pp.113-119
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• 2019

본 연구의 목적은 자동차용 부품에 적용하기 위한 알루미늄 접합 제진 패널에 대한 기계적 특성 및 진동 특성을 도출하기 위한 것이며, 이를 위해서 알루미늄 하이브리드 소재와 알루미늄 원소재의 시험 및 시뮬레이션 결과가 상호 비교되었다. 알루미늄 제진 패널 및 알루미늄 원소재의 인장강도 평가를 통해서 알루미늄 하이브리드 소재의 인장강도 및 인장탄성계수가 알루미늄 원소재 대비 약 10% 내외로 낮음을 확인할 수 있었다. 소재 단위의 해석 및 시험을 통해서 하이브리드 소재가 원소재 대비 낮은 고유진동수를 나타냄을 확인하였고, 하이브리드 소재를 구성하는 수지의 두께가 높아질수록 손실계수가 상승됨을 확인하였다. 또한, 기계적 특성 평가 모사 시뮬레이션을 통해 시험결과와 시뮬레이션 결과가 잘 일치하며, 유한요소해석을 통한 소재의 성능예측이 가능함을 확인할 수 있었다.