• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.57-65
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• 2016

The power flow of an 8-speed automatic transmission was analyzed using a lever analogy for the manufacturing of planetary gears. From the analysis, we found that the engine power was split between the first and second double-pinion planetary gears (DPPG1 and DPPG2), and was then passed to the DPPG3 for the fourth speed. For the fifth speed, the engine power was split between the DPPG1 and DPPG3. For the speeds 6-8, the engine power was passed only to SPPG2, while the seventh speed contained the power circulation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.6
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• pp.483-489
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• 2017

An ultrasonic technique was developed to characterize the resonance behavior of a microcantilever operating in a megahertz regime. A high-power ultrasonic pulser and a contact transducer were employed to excite the silicon microcantilever, and a Michelson interferometer was used to obtain the time domain waveform. The natural frequency of the microcantilever was evaluated through the fast Fourier transform of the signal, and a numerical analysis using the finite element method confirmed the measurement data. The present study proposes a novel and facile method to evaluate nanoscale materials and structures with high sensitivity compared to conventional approaches.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.201-206
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• 2015

이 논문에서는 역학적 지식파 EDISON 구조동역학 서버에서 지원하는 이공계 교육 및 연구용 시뮬레이션 프로그램 중 Co-rotational Plane Beam with Arbitrary Section을 이용하여 캔틸레버 보의 처짐을 기하 비선형적으로 해석한다. 또한 해석에 사용된 프로그램이 실제 교육에 적용이 가능한 지를 고찰함에 그 목적이 있다. 처짐을 해석하기 위하여 수계산, 프로그램을 이용하여 얻은 결과값을 비교하였고 캔틸레버 보의 변화 형상을 시각화 하였다.

• Magazine of the Korea Concrete Institute
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• v.1 no.1
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• pp.115-124
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• 1989

반복하중하에서 휨과 전단거동을 구분할 수 있는 철근콘크리트의 비선형해석 보델이 개발되었다. 개발된 모델은 부재를 single component부재로 이상화시켰으며, 휨과 전단거동을 각각 표현할 수 있는 hysteretic ruless의 결합형태로 이루어졌다. 개발된 모델을 이용한 반복하중을 받는 캔딜레버 보의 해석결과는 실험결과와 비교되었고, 그 결과는 만족스러운 값을 얻었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.661-669
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• 1999

A probe card is one of the most important pan of test systems as testing IC(integrated circuit) chips. This work was related to bump-type silicon vertical probe card which enabled simultaneous tests for multiple semiconductor chips. The probe consists of silicon cantilever with bump tip. In order to obtain optimum size of the cantilever, the dimensions were determined by FEM(finite element method) analysis. The probe was fabricated by RIE(reactive ion etching), isotropic etching, and bulk-micromachining using SDB(silicon direct bonding) wafer. The optimum height of the bump of the probe detemimed by FEM simulation was 30um. The optimum thickness, width, and length of the cantilever were 20 $\mum$, 100 $\mum$,and 400 $\mum$,respectively. Contact resistance of the fabricated probe card measured at contact resistance testing was less than $2\Omega$. It was also confirmed that its life time was more than 20,000 contacts because there was no change of contact resistance after 20,000 contacts.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.153-154
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.618-621
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• 2001

The proposed lever actuator has no friction and mass balance characteristics in motion, which are adapt to high-speed and high-density optical disk system. This paper discussed about the theoretical analysis of the lever structure. The modeling of the lever actuator is found. Using the Newton's method, the motion of equation is deduced through the constraint equations and equilibrium equations in three directions (focusing, tracking and tilting). From the above analysis, we know that the shape of the hinge is the very important parameter on determining the performance of the lever actuator, and the actuator has the 2nd order system characteristics. And the first resonant frequency in transmissibility is dependent to the rigidity of the lever while the first transmissibility resonance of conventional actuators is dependent to the first natural resonance of those actuators. This means that the lever actuator is more stable to the external vibration.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.4
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• pp.69-75
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• 2017

In this study, the performances of five input split type hybrid electric vehicle sub-drivetrains were analyzed. The five sub-drivetrains consist of chain, helical gears and planetary gears. For the analyzing above five sub-drivetrains, the mathematical equations were derived. From the analysis, we found that the sub-drivetrain with chain shows slower acceleration performance and larger energy consumption on the city driving. And, the sub-drivetrain with only helical gear shows smallest energy consumption on the city driving. If the sub-drivetrain can change its gear speed, it shows fastest acceleration performance, but it has largest energy consumption on the city driving due to its additional auxiliary components.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.9
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• pp.41-50
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• 2002

Optical disk system aiming at fast data transfer rate and high-density recording requires the improvement in performance of the pickup head. Especially, the pickup actuator needs better linearity and stability. So, a lever actuator for optical disk is proposed. In this paper, the role of lever and its structure are discussed and the flexure hinge is introduced to enhance the precise movement. Using the Newoton's method, the motion of equation for the lever actuator is obtained. The results are compared with the analysis results by the FEM (Finite Element Method) for the vibration and the magnetic field. Consequently, the lever actuator has the 2"d system characteristics in 3-axis moving directions and superior stability for the external vibration.tion.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.11
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• pp.83-88
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• 2011

The spectral field data on the observation planes inside a mode stirred chamber have been computed by using the FDTD method. They can describe the directional dependence of all supported modes in the reverberation chamber (RC). Correlation coefficients have been found to evaluate the stirring effects. The correlation coefficients were obtained and compared for three different sizes of stirrers and statistical uniformity was investigated.