• 한국자동차공학회논문집
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• 제14권5호
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• pp.155-163
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• 2006

Car seat is one the most important element to make comfortable drivability. It can absorb the impact or vibration during driving state. In addition to those factors, it is needed to have enough strength for passenger safety. From energy efficiency and environmental point of view lighter passenger car seat frame becomes hot issue in the auto industry. In this paper, weight optimization methodology is investigated for commercial car seat frame using CAE. Optimized designs for seat frame are developed using commercially available finite element code(ANSYS) and design of experiment method. At first, car seat frame is modelled using 3-D computer aided design tool(CATIA) and simplified for finite element modelling. Finite element analysis is carried out for the case of FMVSS 202 Head Restraint test to check the strength of the original seat frame. Two base brackets are selected as optimized elements that are the heaviest parts in the seat frame. After finite element analysis for the brackets with similar load condition to the previous test optimization technique is applied for 10% to 50% weight reduction. Design of experiment is utilized to obtain optimization design for the bracket based on the modified 50% weight reduction model in which outer shape of the bracket is conserved. Weight optimization models result in the decrease of the strength in spite of weight reduction. The more design points should be considered to get better optimized model. The more advanced optimization technique may be utilized for more parts of the seat frame to increase whole seat frame characteristics in the future.

• 한국산학기술학회논문지
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• 제15권10호
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• pp.5906-5911
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• 2014

요즈음 생산되는 반도체의 제품이 제대로 작동하는지, 낮은 습도 또는 높은 온도에서 잘 견디는가를 검사하는 패키지 조립 및 검사 공정이 현장에 많이 있다. 또한 검사공정에서 사용되고 있는 반도체 테스트 핸들러 픽커 검사장비가 있는데, 본 연구에서는 CATIA 프로그램을 이용하여 3D 모델링하였으며, ANSYS 프로그램을 이용하여 반도체 테스트 핸들러 픽커 검사장비 프레임의 모델에 대하여 3가지 피로하중에 대한 해석을 하였다. 해석 결과로서 Case 1과 Case 2 모두 프레임의 가운데에서 최대 변형량이 발생하고 불규칙 피로 하중들 중에서 가장 하중의 변동이 심한 'SAE bracket history'가 가장 불안정하고 'Sample history'가 가장 안정함을 보이고 있다. 본 연구의 피로 해석 결과는 반도체 테스트 핸들러 픽커 검사장비 프레임의 파손방지 및 내구성을 검토함으로서 그 프레임의 설계에 효율적으로 활용이 될 수 있다.

• 한국산업융합학회 논문집
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• 제24권5호
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• pp.597-608
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• 2021

The control head components used in small military vessels are designed to be domestically produced, prototypes, structural analysis, and casting methods are designed and cast. The control head assembly consists of a lever, an aluminum outside cover, Middle, front gear cover, back gear cover, and a zinc worm gear. In order to reverse the design of each component, 3D scanning device was used, 3D modeling was performed by CATIA, and prototype productions were carried out by 3D printer. In order to reduce the cost of components, gating system is used by gravity casting method. The SRG ratio of 1:0.9:0.6 was set by applying non-pressurized gating system to aluminum parts, 1:2.2:2.0 and pressurized gating system to zinc parts, and the shapes of sprue, runner and gate were designed. The results of porosity were also confirmed by casting analysis in order to determine whether the appropriate gating system can be designed. The results showed that all parts started solidification after filling completely. ANSYS was used for structural analysis, and the results confirmed that all five components had a safety factor of 15 more. All castings are free of defects in appearance, and CT results show only very small porosity. ZnDC1 zinc alloy worm gear has a tensile strength of 285 MPa and an elongation of 8%. The tensile strength of the four components of A356 aluminum alloy is about 137-162 MPa and the elongation is 4.8-6.5%.

• 대한치과기공학회지
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• 제43권3호
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• pp.99-105
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• 2021

Purpose: This study aims to examine the stress distribution effect of tightening torques of different abutment screws in a custom-abutment implant system on the abutment-fixture connection interface stability using finite element analysis. Methods: The custom-abutment implant system structures used in this study were designed using CATIA program. It was presumed that the abutment screws with a tightening torque of 10, 20, and 30 N·cm fixed the abutment and fixture. Furthermore, two external loadings, vertical loading and oblique loading, were applied. Results: When the screw tightening torque was 10 N·cm, the maximum stress value of the abutment screw was 287.2 MPa that is equivalent to 33% of Ti-6Al-4V yield strength. When the tightening torque was 20 N·cm, the maximum stress value of the abutment screw was 573.9 MPa that is equivalent to 65% of Ti-6Al-4V yield strength. When the tightening torque was 30 N·cm, the maximum stress value of the abutment screw was 859.6 MPa that is similar to the Ti-6Al-4V yield strength. Conclusion: As the screw preload rose when applying each tightening torque to the custom-abutment implant system, the equivalent stress increased. It was found that the tightening torque of the abutment influenced the abutment-fixture connection interface stability. The analysis results indicate that a custom-abutment implant system should closely consider the optimal tightening torque according to clinical functional loads.

• 대한치과기공학회지
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• 제44권3호
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• pp.67-75
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• 2022

Purpose: This study aimed to comparatively evaluate the stress distribution of bones surrounding the implant system to which both titanium and polyetheretherketone (PEEK) abutments are applied using a three-dimensional finite element analysis. Methods: The three-dimensional implant system was designed by the computer-aided design program (CATIA; Dassault Systemes). The discretization process for setting nodes and elements was conducted using the HyperMesh program (Altair), after finishing the design of each structure for the customized abutment implant system. The results of the stress analysis were drawn from the Abaqus program (Dassault Systèmes). This study applied 200 N of vertical load and 100 N of oblique load to the occlusal surface of a mandibular first molar. Results: Under external load application, the PEEK-modeled dental implant showed the highest von Mises stress (VMS). The lowest VMS was observed in the Ti-modeled abutment screws. In all groups, the VMS was observed in the crestal regions or necks of implants. Conclusion: The bones surrounding the implant system to which the PEEK abutment was applied, such as the cortical and trabecular bones, showed stress distribution similar to that of the titanium implant system. This finding suggests that the difference in the abutment materials had no effect on the stress distribution of the bones surrounding implants. However, the PEEK abutments require mechanical and physical properties improved for clinical application, and the clinical application is thought to be limited.

• Steel and Composite Structures
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• 제43권5호
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• pp.523-532
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• 2022

Turbocharger technology is one of the ways to survive in a competitive market that is facing increasing demand for fuel and improving the efficiency of vehicle engines. Turbocharging allows the engine to operate at close to its maximum power, thereby reducing the relative friction losses. One way to optimally understand the behavior of a turbocharger is to better understand the heat flow. In this paper, a 1.7 liter, 4 cylinder and 16 air valve gasoline engine turbocharger with compressible, viscous and 3D flow was investigated. The purpose of this paper is numerical investigation of the number of heat transfer in gasoline engines turbochargers under 3D flow and to examine the effect of different types of coatings on its performance; To do this, modeling of snail chamber and turbine blades in CATIA and simulation in ANSYS-FLUENT software have been used to compare the results of turbine with experimental results in both adiabatic and non-adiabatic (heat transfer) conditions. It should be noted that the turbine blades are modeled using multiple rotational coordinate methods. In the experimental section, we simulated our model without coating in two states of adiabatic and non-adiabatic. Then we matched our results with the experimental results to prove the validation of the model. Comparison of numerical and experimental results showed a difference of 8-10%, which indicates the accuracy and precision of numerical results. Also, in our studies, we concluded that the highest effective power of the turbocharged engine is achieved in the adiabatic state. We also used three types of SiO₂, Sic and Si₃N₄ ceramic coatings to investigate the effect of insulating coatings on turbine shells to prevent heat transfer. The results showed that SiO₂ has better results than the other two coatings due to its lower heat transfer coefficient.

• 한국기계가공학회지
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• 제20권11호
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• pp.67-73
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• 2021

Tanks are key weapons of ground combat that are equipped with powerful weapons and have strong protective bodies. One tank component, the engine clutch flange, is located in the part of the tank where the engine and transmission are installed, and it is a key part of the power transfer and shutoff. The engine clutch flange transmits high power to secure the mobility of the tank; thus, it must have high strength and hardness. In addition, high durability and safety must be ensured because tank operations must exclude concerns about damage. In this study, an engine clutch female flange for tanks made of SNCM439 was developed. The 2D design used AutoCAD programs, and the 3D shape design used CATIA programs. The structural analysis was conducted using ANSYS. The mesh grid has a tetrahedron shape and is created by adding a mid-side node. After the mechanical properties and constraints of SNCM439 were entered, the changes in the safety factor, total deformation, and Von-Mises stress were identified according to the increase in torque. Prototype processing was performed to verify the engine clutch female flange for the tank. To determine the productivity of the product, the cutting processing time was measured when processing the prototypes. Based on the results of measuring the cutting processing time, it is concluded that research is needed to improve productivity because MCT slot cutting processing is time consuming.

• 한국간담췌외과학회지
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• 제27권1호
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• pp.102-106
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• 2023

Hepatocellular carcinoma (HCC) accounts for most of the hepatic neoplasms and can also occur in ectopic liver tissue. We present a case of a 55-year-old male complaining of weight loss. The imaging studies reported a 2.9 cm nodule in the pancreatic body, with a neuroendocrine tumor diagnosis by cytology. A corpo-caudal pancreatectomy was performed. Pathology showed a well-differentiated HCC developed in ectopic liver tissue with free margins and no lymph node metastases. HCC presenting in ectopic liver tissue is rare. In this case, the preoperative study did not establish the diagnosis, warranting the need for suspicion of this neoplasm.

• 현장농수산연구지
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• 제11권1호
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• pp.79-94
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• 2009

본 연구는 우리나라 식용포도 재배농가의 보호봉지 결속작업이 주로 고령의 부녀자에 의존하고 있어 향후 이들 노동력을 대체하기 위하여 기계적인 포도보호봉지 결속장치를 개발하여 생산비를 절감하고자 얻어진 결과 는 다음과 같다. 1. 포도 보호봉지 및 포장봉지 결속기 개발 가. 자동결속기 설계는 CATIA V12/AUTOCAD 2000으로 하였다. 나. 자동결속기는 포도보호봉지를 기계적으로 묶어주는 장치로 소형, 경량이어야 하며 작업 시간, 노동량을 줄어 젊은층에서부터 고령자까지 작업할 수 있도록 설계하였다. 다. 자동결속기의 총 무게는 350g이하 초경량으로 제작될 수 있도록 하였다. 라. 결속성공률은 99%이상이 되도록 하였다. 마. 자동결속기의 결속롤과 커터, 배터리, 모터 등의 구조를 스테플러와 같은 가트리지형태로 개발하였다. 바. 카트리지 핀은 C-ring 28mm형으로써 길이는 500mm정도로 포도보호봉지 및 제과·제빵포장봉지를 결속할 수 있도록 제작하였다. 사. 작업시 포도나무 포도넝쿨 등 장애물의 영향을 받지 않도록 디자인을 설계, 제작하였다. 2. 포도보호봉지 결속작업시스템 포장실증시험 가. 자동결속기 시작기를 이용한 포도 보호 봉지결속으로 시기별 과병장, 과식품질이 무처리에 비하여 현저히 높았다. 나. 포도보호봉지 결속작업은 숙련자의 경우 1일 3,000개내외 씌우는 반면 초보자는 1,200개(37%)정도로 크게 떨어졌다. 다. 포도 보호봉지 자동결속기를 이용한 작업효율성은 102%로써 숙련자의 노동력을 대체할 수 있을 것으로 판단되었다. ∘ 1단계 : 232.5%(앞치마에서 보호봉지를 꺼내어 포도에 씌움) ∘ 2단계 : 60.7%(씌운 보호봉지 주름을 잡음) ∘ 3단계 : 104.7%(주름이 잡힌 상태에서 결속) ∘ 4단계 : 102% 라. 포도 보호봉지 결속부위의 둘레(크기)를 조사한 바 관행보호봉지결속작업(수작업)에서는 손으로 철사핀을 감기 때문에 평균 4.6cm이었으며 자동결속기의 결속롤(핀)은 5.3cm가 되어 다소 줄이는 것이 정밀성이 높을 것으로 판단되었다. 마. 수확시 과실 품질(과중, 과방크기-과장, 과폭, 가용성고형물, 산함량)을 조사한 결과 처리한 차이가 인정되지 않았다. 바. 자동결속기를 이용한 포도보호봉지 결속작업처리에서 포도의 열과(터진포도)와 이병율 차이에는 관행방법과 차이가 없었다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2017년도 춘계공동학술대회
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• pp.80-80
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• 2017

국내에서 대부분 생산되는 사료(사일리지) 수확 작업은 베일 생산 및 비닐 래핑 작업이 독립적으로 수행되고 있어서 비효율적이다. 본 연구에서 개발한 조사료 수확기는 수집, 롤링, 베일 네트 생성, 래핑, 래핑 종료 및 베일 방출작업을 통합적으로 수행하도록 설계-제작하였다. 통합형 다목적 조사료수확기의 설계는 3D 디자인 툴 (CATIA V5R18)을 이용하여 실시하였으며, 기구부 23 파트 어셈블리, 전기제어 어셈블리, 유압요소기술을 통합하여 통합시작기를 제작하였다. 기초 프레임, 오거장치파트, 픽업장치파트, 하부롤러파트, 상부롤러파트, 하부 프레임 및 주행부 파트, 래핑회전파트, 롤러부 구동 동력부, 유압파트, 전기제어파트, 드로우바파트, 체결 및 컨트롤러 파트 등 25개 파트로 구성되어 있다. 본 연구에서 개발한 시작기의 견인력 및 소요동력 분석은 선행 연구에서 사용한 Brixius (1987) 제안 모델을 체택하여 분석하였다. 이 Brixius 제안 모델은 견인력 예측에서 토양변수 및 토양강도 특성을 나타내는 원추지수 (Cone Index, CI)를 이용하여 트랙터의 견인력 예측에 사용하였다. 또한 트랙터-조사료수확기 시스템의 소요 견인력을 예측하는데 있어, 트랙터-조사료수확기 시스템이 운용되는 토양조건과 트랙터의 마력에 따른 소요 견인력 특성을 분석하기 위해 대표적으로 3수준의 토양조건 (CI: 356 kPa, 543 kPa, 1,429 kPa)을 적용하였으며, 베일의 개당 최대무게는 최고 수준인 옥수수 기준으로 800 kgf를 적용하였다. 본 연구에서 적용된 3수준의 CI 조건은 연구팀에서 선행연구과정 (토양특성에 따른 최적 경운작업 시스템 개발, 2006)에서 분석한 전국 10개 지역의 33개 지점의 경반층 CI지수의 측정범위인 1,050-3,170 kPa에 대해 견인력이 많이 소요되는 열악한 조건 수준을 적용하였다. 각 작업에 사용된 소요동력은 베일 작업시 (ASABE D497.7, 2011) 그리고 래핑작업시 (Zhortuylov et al., 2013)를 사용하였으며 두 소요마력을 트랙터-조사료 수확기 시스템의 필요 소요마력의 합계로 계산하였다. 트랙터-조사료수확기 시스템의 최소 소요 동력, 차축 소요 동력과 PTO 소요 동력을 Zoz and Grisso (2003)을 이용하여 계산하였다. 연구에서는 기본적으로 ASAE의 작업속도 및 작업효율을 적용하였는데, 적용된 조사료수확기의 현장 작업효율은 60-86%의 범위이고 일반적으로 70%를 적용하고 이때 작업속도는 2.5-8.0 km/h이며 전형적으로 5.0 km/h를 기준하고 있다. 자주식 (SP; sief-propelled machine) 조사료수확기의 경우 작업속도가 2.5-10.0 km/h의 범위에서 작업효율은 60-85% 범위이다. 적용되는 조사료 수확기의 작업효율인 60-85% 범위에서 일반적으로 적용되는 작업효율인 70%를 적용하면 트랙터의 소요동력은 95hp를 적정 작업환경으로 하였다.