• Journal of Welding and Joining
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• v.24 no.6
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• pp.28-32
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• 2006

Laser Transmission Joining (LTJ), which is a joining process of polymers by using different transmission rates of materials, was studied numerically. Unlike previous studies, energy loss by reflection at the surface was included. Besides, energy absorbed in the transparent substrate is also considered to increase the accuracy of the analytical results. Furthermore, thermal deformations of the substrates were also calculated. Temperature distribution of the substrates on the joining process could be effectively predicted by using the thermal analysis model developed, which could also analyze the rising phenomenon of the absorbing substrate by bulge effect. Calculated results show that temperature of the absorbing substrate is higher than that of transparent substrate when the laser is being radiated, and this temperature difference causes more thermal deformation in absorbing substrate, which results in the surface rise of the absorbing substrate. Comparison of calculated results with corresponding experimental results could confirm the validity of the numerical analysis model proposed.

• Journal of Welding and Joining
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• v.25 no.2
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• pp.43-48
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• 2007

Laser Transmission Joining (LTJ) of plastics is a process in which light of suitable wavelength is transmitted through a transparent substrate that is in contact with an absorbing one. In this paper, LTJ is investigated by preliminary experiments from the viewpoint of mechanical engineering. To understand transmitting characteristics of each polymer substrate, transmission rate, reflection rate and absorption coefficient of polymer are measured by using a laser power-meter. Characteristics of joining in the spot welding and seam welding are investigated by measuring the fracture load. Fracture load increases in accordance to the laser power and irradiation time. However, when the laser power is over 60W and irradiation time over 4seconds, fracture load decreases. This phenomenon is probably due to heat-softening of materials. Besides, cavities are generated at a joint by evaporation of water molecules, which can be suppressed by introduction of a gap between two substrates.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.1
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• pp.46-52
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• 2012

A PAEM(Pneumatic Active Engine Mount) system has been developed to improve NVH performance of a SUV in idle state. Control objective to attenuate the vibration of a vehicle should be determined prior to the design of control algorithm. This study presents the correlation analysis of output variables of PAEM system by means of TPA(Transfer Path Analysis) using experimental data obtained by vehicle test. The analysis results show that the vibration of vertical direction is more serious than those of longitudinal and lateral direction of the vehicle, and that the correlation between the vibration of front seat rail and that of steer wheel is highest. In conclusion, the vibrations of front seat rail and steer wheel in vertical direction should be considered as the control objectives of the PAEM.

• Polymer(Korea)
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• v.30 no.4
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• pp.311-317
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• 2006

Poly-DCPD and poly-DCPD/silicates hybrids were prepared by in-situ ROMP poly-merization using $WCl_6$ catalyst. Good dispersion of silicates in DCPD medium can be accomplished by sonication method. Compared with nanocomposites prepared using $Na^+MMT$, the nanocomposites with CL 15A showed well dispersed silicate's morphology. superior thermal and mechanical properties. Additionally, well dispersed silicates in DCPD matrix enhanced the gas barrier property of the nanocomposites.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3849-3855
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• 2012

This paper describes a control algorithm and test results of an automated manual transmission clutch actuated by a stepping motor. The control algorithm extracts driver's demand from CAN signals and decides the exact timing to engage or disengage the clutch based on the demand. A pulse signal is generated to drive the clutch and the travel of the clutch can be calculated by accumulating the pulse signal. An auto code generation method was introduced in implementing the control logic to the micro-processor of the prototype controller and a series of basic tests were carried out to validate its performance.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.607_608
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• 2009

일반적으로 매입형 영구자석 동기전동기는 영구자석의 사용량이 많을수록 돌극비를 향상 시킬 수 있으므로 발생토크 중 릴럭턴스 토크의 비중을 키울 수 있다. 이는 토크 발생 시 입력전류를 저감시켜 동손이 감소하고 효율을 향상시키는 효과를 기대할 수 있다. 하지만 최근에 희토류계 영규자석의 가격 상승으로 인하여 영구자석 형 전동기 개발에 있어 제약이 따르는 상황이며 가격 경쟁력을 위하여 영구자석의 사용량을 저감시키는 노력을 기울이고 있다. 본 논문에서는 HEV 구동용 매입형 영구자석 동기전동기를 대상으로 영구자석 사용량 저감 설계에 대하여 다루고자 한다. 영구자석 사용량 저감은 영구자석의 두께를 변경시켜서 검토하였으며 실험을 통한 영구자석의 감자특성을 검토하여 최적의 두께를 결정하였다. 영구자석 두께 저감에 따라 감소한 최대출력 확보를 위하여 회전자의 형상설계를 기계적 구조해석과 병행하여 수행하였다. 최종으로 설계된 모델의 특성은 Prototype과 비교하여 성능만족 여부 및 영구자석 사용량 변화를 확인하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.103-109
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• 2008

Semi-spherical CVT(SS-CVT) is one of friction drives, which transmits power via the friction force between a spherical shaped variator and output disks. The variator varies the speed ratio of SS-CVT continuously as well as transmits input power into the output shaft. Therefore two friction forces are normally applied on the variator; one is the longitudinal friction force for power transmission and the other is the lateral for shifting. In order to investigate the dynamic behavior of SS-CVT, we introduced a numerical model of 2-dimensional friction force using a function of slip ratio and slip angle. And a dynamic model, which describes the shifting mechanism of SS-CVT, is developed through 3-dimensional vector analysis. Finally we presented numerical results of the shift characteristics focused on the transient behavior of the variator's slip ratio and slip angle. The numerical results also show the typical CVT shifting characteristics of SS-CVT and stable shifting behaviors of the variator.

• Journal of the Korean Operations Research and Management Science Society
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• v.42 no.2
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• pp.49-61
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• 2017

The study on the efficiency analysis of Korean automobile parts companies is mostly based on the calculation of the size of output such as sales. However, the performance indicators such as sales, operating profit, and net profit are directly related to the cost structure, and this cost structure is affected by changes in the company's asset structure and capital structure. As a result, it is necessary that efficient capital procurement should be done at the same time to create efficient management performance through proper investment. In this study, we aim to measure the efficiency of asset and capital procurement compared to the sales figures, such as sales, generated by 33 primary suppliers who supply parts to Hyundai Kia Motors. For this purpose, this study proposed a DEA cross analysis model that can simultaneously measure efficiency in terms of input assets and capital procurement based on the same management performance when analyzing the efficiency of domestic auto parts companies.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.33-35
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• 2005

In this paper, a two-mass system for SiOG (Silicon on Glass) vibratory gyroscope with the need of frequency tuning was proposed to increase the stability of the device with wide bandwidth. Air damping and bandwidth were analyzed using MATLAB. The measured resonance frequency is 5.2 kHz, which is 7 kHz in the design. But the measured bandwidth is 450 Hz, similar to the designed bandwidth with 500 Hz. Also the frequency difference (210 Hz) between the driving and sensing part is smaller than the wide bandwidth of two mass system.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.756-757
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• 2008

Interior permanent magnet synchronous motor (IPMSM) which has high power density is usually applied to traction motor for hybrid electric vehicle. In order to analyze characteristics of IPMSM, d- and q-axis equivalent circuit analysis is generally used. However, the line current of IPMSM calculated by d- and q-axis equivalent circuit analysis differ from measured value. This error is mainly appeared under the flux weakening control. In order to reduce the error between calculated and measured line current, no-load linkage flux which is calculated with considering saturation of magnetic core and armature reaction is applied to characteristic analysis. The result of line current calculated by the method dealt with in this paper is verified by comparison with experimental results.