시험 규격을 고려한 자동차 페달 암의 구조해석과 위상최적화

이부윤,이현우,Lee Boo-Youn,Lee Hyun-Woo 한국마린엔지니어링학회 2006 한국마린엔지니어링학회지 Vol.30 No.5

Finite element analysis is performed to evaluate structural reliability of an automotive pedal arm under conditions of the stiffness, the load and the endurance test specifications. Results of the analysis shows that the pedal arm is safe enough under the tests. A topology optimization is numerically implemented, overall shape of the pedal arm being verified to be reasonable, A design concept to insert holes in the arm is established, which may be used to reduce its weight.

섬유판 제작용 압연프레스 가열드럼의 피로수명 해석과 구조설계 개선에 관한 연구

이부윤,Lee Boo Youn 한국마린엔지니어링학회 2005 한국마린엔지니어링학회지 Vol.29 No.2

Stress and fatigue life analyses are performed to enhance a fatigue life of a heating drum of the roller press for medium density fiberboard. The finite element method employing the submodel is used to analyze stress concentration in the journal of the heating drum. The fatigue life is evaluated by the stress-life theory. Two modified designs of the journal are suggested and evaluated to reduce the maximum stress and to increase the fatigue life Their structural reliabilities are verified in terms of the yield strength and the design life.

발전용 증기터빈 밸브 케이싱의 유한요소해석과 주조결함 평가 방법

이부윤,김원진,신현명,Lee Boo-Youn,Kim Won-Jin,Shin Hyun-Myung 한국마린엔지니어링학회 2005 한국마린엔지니어링학회지 Vol.29 No.5

Stresses of main stop valve and control valve casings for the steam turbines of power plants are analyzed by the finite element method. The stress intensity is obtained to check the results on the basis of the design criteria of ASME boiler and pressure vessel code. To verify accuracy of the finite element analysis. analyzed stresses are compared with those measured during the hydrostatic pressure test. Stress category drawings. which play an important role in evaluating casting defects, are produced from the analysis results, and important points in casting of the valve casings are discussed in terms of the stress category.

경계요소법에 의한 축대칭 탄성체의 형상설계 민감도해석을 위한 직접미분법과 터빈 디스크의 형상최적설계

이부윤,Lee, Bu-Yun 대한기계학회 1996 大韓機械學會論文集A Vol.20 No.5

A direct differentiationmethod is presented for the shape design sensitivity analysis of axisymmeetric elastic solids. Based on the exisymmetric boundary integralequaiton formulation, a new boundary ntegral equatio for sensitivity analysis is derived by taking meterial derivative to the same integral identity that was used in the adjoint variable melthod. Numerical implementation is performed to show the applicaiton of the theoretical formulation. For a simple example with analytic solution, the sensitivities by present method are compared with analytic sensitivities. As an application to the shape optimization, an optimal shape of a gas turbine disc toinimize the weight under stress constraints is found by incorporating the sensitivity analysis algorithm in an optimizatio program.

캐비닛-도어 통합모델을 이용한 빌트인 양문형 냉장고의 도어 상하단차와 앞뒤단차 해석

이부윤(Boo-Youn Lee) 한국기계가공학회 2018 한국기계가공학회지 Vol.17 No.5

A cabinet-door integrated finite element model was constructed for a built-in side-by-side refrigerator with an ice dispenser, and its deformation was analyzed using the ANSYS finite element software. As loads, the food load needed to fill in the cabinet and doors and the thermal load occurring during normal operation conditions were taken into consideration. The door height difference (DHD) and door flatness difference (DFD) between the two doors of the freezing and refrigerating compartments were derived. The DHD and DFD under the assembled condition without applied loads satisfied the acceptance criteria specified by the refrigerator manufacturer. It appeared that the food load increases the DFD slightly. The thermal load tends to increase the differences because of the thermal deformation, especially the DFD, of the cabinet and doors.

OLED 증착용 마스크 프레임의 무게 최소화를 위한 형상최적설계

이부윤(Lee, Boo-Youn) 한국산학기술학회 2013 한국산학기술학회논문지 Vol.14 No.10

본 연구는 FMM 방식을 사용하는 OLED 디스플레이의 증착공정에서 사용되는 마스크 프레임의 무게를 최 소화하기 위한 형상최적설계를 다루었다. 위상최적화 해석을 수행하였으며 그 결과를 토대로 프레임의 가로 및 세로 변에 슬롯을 삽입함으로써 강성을 증가시키면서 무게를 저감시킬 수 있는 설계 개념을 도출하였다. 프레임의 형상설 계변수를 정의하고 형상최적설계 문제를 정립하여 수치적 최적화를 수행하였다. 프레임의 설계기준인 최대 변위의 제 약조건을 만족하면서 무게가 최소인 프레임의 최적형상을 성공적으로 구하였으며, 최적설계된 프레임의 무게는 117.6 kg으로 최초설계안 256 kg 대비 138.4 kg(54.1%)가 감소된 결과를 얻었다. Present work deals with a shape optimal design to minimize the weight of the mask-frame used in the process of OLED vapor deposition by the fine metal mask. A design concept for an optimal shape of the frame to increase the stiffness and to reduce the weight is derived using the topology optimization, shape design variables of the frame by adopting slots being defined. An optimal shape is determined by solving the shape optimization problem to minimize the weight of the frame under constraints of the maximum displacement. Weight of the optimal design is 117.6 kg, which is reduced by 138.4 kg(54.1%) of that of the first design, 256 kg.

응력집중 저감을 위한 트랙터용 프론트 로더의 설계개선 및 충격 안전성 평가

이부윤(Boo-Youn Lee) 한국기계가공학회 2018 한국기계가공학회지 Vol.17 No.3

The purpose of this study is to evaluate the structural safety of the front-end loader for the 90 kW class of agricultural tractors in impact test conditions. Deformation and stress on the loader under the impact test conditions are analyzed using the commercial finite element analysis software ANSYS. In previous research dealing with the initial design of the loader, the maximum stress occurred in the mount and exceeded the yield strength of the material. In this paper, an improved design of the mount of the loader was proposed to reduce the stress concentration in the initial design. The safety of the improved design was verified by performing rigid-body dynamics analysis, transient structural analysis, and static structural analysis under three impact test conditions: a drop and catch test, a corner pull test, a corner push test. It was found that the local stress concentration in the mount that appeared in the initial design was greatly reduced in the improved design, and that the maximum stresses occurred in the three impact test conditions are smaller than the yield strength. It is expected that the design improvement of the mount proposed in this study and the method of analysis may be effectively used to enhance structural safety in the development of new model front loaders in the future.

유럽기준을 적용한 배열회수보일러 고압드럼의 응력 및 피로 평가

이부윤(Boo Youn Lee) 대한기계학회 2018 大韓機械學會論文集A Vol.42 No.9

배열회수보일러 고압드럼에 대하여 EN Code와 ASME Code를 적용하여 설계피로를 평가하였다. 설계조건의 응력과 과도운전조건의 응력범위는 EN Code의 평가기준을 만족하였다. 과도운전조건을 고려하여 EN Code와 ASME Code를 적용하여 설계피로를 계산하였다. 대표적 위치인 쉘-노즐 용접부 핫스팟과 비용접부인 보어의 피로수명은 두 Code의 피로 평가기준을 만족하였다. 두 Code에 의한 누적피로 사용계수는 비용접부에서는 비슷한 수준이지만, 용접부에서는 EN Code가 ASME Code보다 보수적인 결과를 보였다. 본 연구에서 제시된 EN Code의 적용 방법 및 실제 적용 사례는 유사한 압력용기의 설계검증 과정에서 널리 활용될 수 있을 것으로 기대된다. The design fatigue of a high-pressure drum in a heat recovery steam generator was evaluated according to EN and ASME codes. The stress for the design condition and stress range for transient operating conditions are demonstrated to satisfy the criteria of the EN code. The cumulative fatigue usage factors at several representative shell–nozzle weld hotspots and the bores were calculated by applying both codes, and are shown to satisfy the criteria. It was found that the usage factors calculated using the two codes are similar in the non-welded area, but the EN code produces more conservative results for the welded areas than the ASME code. The method for the practical application of the EN code presented in this study can be widely used in the design verification process of similar pressure vessels.

석탄화력발전소 보일러의 멤브레인벽을 위한 등가 쉘요소의 직교이방성 탄성상수 결정 방법

이부윤(Boo-Youn Lee) 한국기계가공학회 2020 한국기계가공학회지 Vol.19 No.3

In this study, we proposed a method to replace the solid finite element model of the boiler membrane wall for coal-fired power plants using an equivalent shell model. The application of a bending load to the membrane wall creates greater displacement at both ends of the central portion when compared with the middle when an isotropic elastic constant is used in the shell model. This is inconsistent with the results of the solid model where the central portion is uniformly deformed. Here, we presented a method to determine the orthotropic elastic constants of the shell model in terms of bending stiffness and vibration characteristics to solve this problem. Our analysis of the orthotropic shell model showed that the error ratio was 0.9% for the maximum displacement due to the bending load, 0.3% for the first natural frequency, and 2.5% for the second natural frequency when compared with the solid model. In conclusion, a complicated boiler membrane wall composed of a large number of pipes and fins can be replaced with a simple shell model that shows equivalent bending stiffness and vibration characteristics using our proposed method.

빌트인 냉장고 댐핑힌지의 응력해석 및 파손방지를 위한 설계개선

이부윤(Boo-Youn Lee) 한국기계가공학회 2020 한국기계가공학회지 Vol.19 No.2

The damping hinge of a built-in refrigerator was examined in terms of its stress and fatigue life. Analysis of the initial design showed that stress concentration occurred at the concave surface of the hinge lever, which was broken during the door opening-and-closing endurance test of the prototype. The maximum von Mises stress at this location exceeded the yield strength. In addition, Goodman fatigue analysis of the initial design showed that the fatigue life at this location was consistent with the failure observed during the endurance test. Based on these results, an improved design for the damping hinge was derived. Analysis of this improved design showed that the stress concentration in the hinge lever of the initial design was eliminated. In this case, the maximum stress occurred at the position where the hinge lever was in contact with the door stopping pin, and the maximum von Mises stress was smaller than the yield strength. Goodman fatigue analysis of the improved design indicated that the fatigue life of the entire damping hinge was infinite. It was therefore concluded that the improved design does not suffer from fatigue damage during the endurance test.