무한궤도 보기륜의 정밀 단조 및 굽힘 강도 개선 연구

정도현,김현중,한태희,이상욱,이상욱 순천향대학교 산업기술연구소 2025 순천향 산업기술연구소논문집 Vol.31 No.2

This study presents a structural design to enhance the bending strength of a bogie wheel for tracked vehicles through precision forging. The forging die was designed using AutoCAD, Inventor, and SolidWorks, and the rim thickness of the base model was reduced by 20% to add eight internal reinforcement ribs. AFDEX simulations confirmed stable formability, and ANSYS analysis under a 30 kN load showed up to an 80% reduction in maximum elastic strain depending on rib height. The proposed design effectively improves bending resistance without weight increase, providing a practical solution for improving the structural durability of defense components.

Wetting Balance Test를 이용한 솔더의 젖음성 분석

정도현,임동욱,백범규,임송희,윤종혁,정재필,Jung, Do-hyun,Lim, Dong-uk,Baek, Bum-gyu,Yim, Song-hee,Yoon, Jong-hyuk,Jung, Jae Pil 한국마이크로전자및패키징학회 2017 마이크로전자 및 패키징학회지 Vol.24 No.2

Recently, there has been a continuous researches on solders having sophisticated and improved performance due to demand for high-density and miniaturization of electronics, and development of solder for automotive electronics which can be used in harsh environment. When developing a new solder alloy, there is a wettability of solder on substrate for things to consider, and the wetting balance test is one of the methods for measuring that one. In this paper, the wetting balance test is introduced, and the calculus of the surface tension of solder and the contact angle between solder and substrate using wetting curve obtained is introduced too. In detail, the principle and test method of the wetting balance test, the introduction of the parameters with important meaning in the wetting curve, the method of calculating the contact angle as well as the surface tension of the solder using the shape of the solder meniscus.

전자 패키징용 고신뢰성 나노입자 강화솔더

정도현,백범규,임송희,정재필 한국마이크로전자및패키징학회 2018 마이크로전자 및 패키징학회지 Vol.25 No.2

In the soldering industry, a variety of lead-free solders have been developed as a part of restricting lead in electronic packaging. Sn-Ag-Cu (SAC) lead-free solder is regarded as one of the most superior candidates, owing to its low melting point and high solderability as well as the mechanical property. On the other hand, the mechanical property of SAC solder is directly influenced by intermetallic compounds (IMCs) in the solder joint. Although IMCs in SAC solder play an important role in bonding solder joints and impart strength to the surrounding solder matrix, a large amount of IMCs may cause poor strength, due to their brittle nature. In other words, the mechanical properties of SAC solder are of some concern because of the formation of large and brittle IMCs. As the IMCs grow, they may cause poor device performance, resulting in the failure of the electronic device. Therefore, new solder technologies which can control the IMC growth are necessary to address these issues satisfactorily. There are an advanced nanotechnology for microstructural refinement that lead to improve mechanical properties of solder alloys with nanoparticle additions, which are defined as nano-reinforced solders. These nano-reinforced solders increase the mechanical strength of the solder due to the dispersion hardening as well as solderability of the solder. This paper introduces the nano-reinforced solders, including its principles, types, and various properties.

알루미늄 합금과 그 접합 방법

정도현,정재필 한국마이크로전자및패키징학회 2018 마이크로전자 및 패키징학회지 Vol.25 No.2

Aluminum (Al) and its alloys have been used widely in a variety of industries such as structural, electronic, aerospace, and particularly automotive industries due to their lightweight characteristic, outstanding ductility, formability, high oxidation and corrosion resistance, and high thermal and electrical conductivity. Al have different kinds of alloys according to the various additional elements system and they should be selected properly depending on their effectiveness and suitability for their particular purpose. The major elements for Al alloys are silicon (Si), magnesium (Mg), manganese (Mn), copper (Cu), and zinc (Zn). In order for Al alloys to use for each industry, it is necessary to study of Al to Al joining and/or the Al to dissimilar materials joining to combine the individual parts into one. Many studies on joining technologies about Al to Al and Al to dissimilar materials have been performed such as press joining, bolted joint, welding, soldering, riveting, adhesive bonding, and brazing. This study reviews a variety of Al alloys and their joining method including its principles and properties with recent trends.

고온동작소자의 패키징을 위한 천이액상확산접합 기술

정도현,노명환,이준형,김경흠,정재필,Jung, Do-hyun,Roh, Myung-hwan,Lee, Jun-hyeong,Kim, Kyung-heum,Jung, Jae Pil 한국마이크로전자및패키징학회 2017 마이크로전자 및 패키징학회지 Vol.24 No.1

Recently, research and application for a power module have been actively studied according to the increasing demand for the production of vehicles, smartphones and semiconductor devices. The power modules based on the transient liquid phase (TLP) technology for bonding of power semiconductor devices have been introduced in this paper. The TLP bonding has been widely used in semiconductor packaging industry due to inhibiting conventional Pb-base solder by the regulation of end of life vehicle (ELV) and restriction of hazardous substances (RoHS). In TLP bonding, the melting temperature of a joint layer becomes higher than bonding temperature and it is cost-effective technology than conventional Ag sintering process. In this paper, a variety of TLP bonding technologies and their characteristics for bonding of power module have been described.

6-도메인 스마트팩토리 성숙도 평가 모델 기반 도입기업 군집분석

정도현,안정현,최상현,Jeong, Doorheon,Ahn, Junghyun,Choi, Sanghyun 한국융합학회 2020 한국융합학회논문지 Vol.11 No.9

Smart Factory is one of the fastest developing and changing fourth industrial revolution fields. In particular, the degree of introduction and maturity level in the smart factory is an important part. In this paper, a cluster analysis of companies introduced smart factory was performed based on a new maturity assessment model. The 68% of 193 companies surveyed were at the basic level, with only 21% being the middle one. Most SMEs cited lack of funds as the main reason for not entering the middle one. As a result of the cluster analysis, it was found that all clusters had similar patterns but grouped into one of three levels of high, middle, and low depending on maturity level of smart factory operation, and process domain had the highest maturity and data domain was lowest among the 6 domains. Through this, analysis of more specific and quantified maturity levels can be performed using 6-domain smart factory maturity evaluation model.

확률조건의 근사화를 통한 효율적인 강건 최적설계 기법의 개발

정도현,이병채,Jeong, Do-Hyeon,Lee, Byeong-Chae 대한기계학회 2000 大韓機械學會論文集A Vol.24 No.12

Alternative formulation is presented for robust optimization problems and an efficient computational scheme for reliability estimation is proposed. Both design variables and design parameters considered as random variables about their nominal values. To ensure the robustness of objective performance a new cost function bounding the performance and a new constraint limiting the performance variation are introduced. The constraint variations are regulated by considering the probability of feasibility. Each probability constraint is transformed into a sub-optimization problem and then is resolved with the modified advanced first order second moment(AFOSM) method for computational efficiency. The proposed robust optimization method has advantages that the mean value and the variation of the performance function are controlled simultaneously and the second order sensitivity information is not required even in case of gradient based optimization. The suggested method is examined by solving three examples and the results are compared with those for deterministic case and those available in literature.

임도사면 녹화식물의 침식 억지 효과

정도현,지병윤,전권석,김종윤 한국산림과학회 2004 한국임학회 학술발표논문집 Vol.2004 No.-

임도사면 녹화식물의 토양 고정 효과

정도현,지병윤,전권석,김종윤 한국산림과학회 2004 한국임학회 학술발표논문집 Vol.2004 No.-

Reliability prediction of the fatigue life of a crankshaft

정도현,김홍진,편영식,Alisher Gafurov,최규철,안종모 대한기계학회 2009 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.23 No.4

Crankshaft, the core element of the engine of a vehicle, transforms the translational motion generated by combustion to rotational motion. Its failure will cause serious damage to the engine so its reliability verification must be performed. In this study, the S-N data of the bending fatigue limit of a crankshaft are derived. To evaluate the reliability of the crankshaft, reliability verification and analysis are performed. For the purpose of further evaluation, the bending test of the original crankshaft is carried out, and failure mode analysis is made. The appropriate number of samples, the applied load, and the test time are computed. On the basis of the test results, Weibull analysis for the shape and scale parameters of the crankshaft is estimated. Likewise, the B10 life under 50% of the confidence level and the MTTF are exactly calculated, and the groundwork for improving the reliability of the crankshaft is laid.