• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.261-264
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• 2006

Many process parameters have an effect on the auto-body panel forming process. A well-designed blank shape causes the material to flow smoothly, reduces the punch and yields a product with uniform thickness distribution. Therefore, the determination of an initial blank shape plays the important role of saving time and cost in the auto-body panel forming process. For these reasons, some approaches to estimate the initial blank shape have been implemented in this paper, the one-step approach by using a finite element inverse method will be introduced to predict the initial blank shape the developed program is applied to auto-body panel forming.

• 소성∙가공
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• 제15권3호
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• pp.241-246
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• 2006

The isotropic steel sheet was developed and started to apply on the auto-body outer panel, however the characteristics of application on auto-body were not well known. In this paper the FE analysis of outer panel of auto-body was carried out to investigate the characteristics of isotropic steel sheet. For the FE analysis of the roof panel of ULSAB body the isotropic steel sheet and the bake hardening steel sheet were used. The Isotropic steel sheet shows more deformation at punch bottom area of roof panel than the bake hardening steel sheet that is most required forming properties far outer panel to obtain the shape likability of forming parts. It is shown that the isotropic steel sheet has suitable material properties far outer panels of auto-body.

• 유통과학연구
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• 제18권1호
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• pp.59-69
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• 2020

Purpose: This study aims to examine such relationships as the experiential value that customers respond to with regard to maintenance service by empirically revealing how the quality of auto maintenance and repair service affects both customer satisfaction and intention to reuse the same service through the Perceived-experiential Value of customers. Research design, data and methodology: The research model was designed with service qualities such as human quality, material quality, interaction quality, and system quality as independent variables, perceived-experiential value as a parameter, and service satisfaction and return visit intention as dependent variables. Through a questionnaire composed of 24 items, a total of 319 survey data from customers with the experience of using car maintenance service centers in Korea were collected and analyzed using a structural equation. Results: The material quality did not affect the customers' perceived-experiential value, whereas the interaction quality had the greatest influence. It is confirmed that human quality, interaction quality, and system quality can generate customer satisfaction and repurchase intention through the perceived-experiential value. Conclusions: The experiential value of customers can play an important medium role in improving satisfaction, with customers considering interaction quality important. Therefore, the auto maintenance and repair service should consider relationship-focused service strategies.

• 한국레이저가공학회지
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• 제9권3호
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• pp.7-13
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• 2006

Auto focusing system to find optimized focal position of laser beam used for material process has been investigated by using fiber confocal method. Wavelength of laser diode (LD) and diameter of single-mode fiber are 780nm and $5.3{\mu}m$, respectively. Intensity distributions of beam reflected from the surface of mirror and silicon bare wafer have been observed in a gaussian form. Experimental results show that focal position obtained by LD is shifted from one observed from surface scribed by laser about $80{\mu}m$. It is due to the difference of wavelength and each divergence of between LD and laser used for material process. It is confirmed that auto focusing control system through position calibration has operated steadily.

• 한국자동차공학회논문집
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• 제16권6호
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• pp.115-120
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• 2008

There are many typesof accelerometer sensor. There was mainly used high-g accelerometer to obtain data for vehicle in crash test. Accelerometer was mounted on test vehicle with mounting blocks. Test result can be influenced by condition of mounting i.e. bonding material and type of block. These influences can be evaluated to variation of sensitivity in calibration test. In this paper, Calibration test were carried out for 3 types of bonding material i.e. stud, beewax and double side tape. Other factor was taken into consideration by 3-types for mounting block. All test was conducted by sinusoidal signal vibrator up to 4500Hz. In order to investigate influence for sensitivity from different input voltage in the calibrator, the same test was repeated. Test results were compared with standard accelerometer data. Relative sensitivities and phases were showed small difference in sensitivity for bonding materials with one block, but significant one for another block and different input voltage below 1000Hz.

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 2006년도 추계학술발표대회 논문집
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• pp.41-45
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• 2006

Auto focusing system to find optimized focal position of laser beam used for material process has been investigated by using fiber confocal method. Wavelength of laser diode (LD) and diameter of single-mode fiber we 780nm and $5.3{\mu}m$, respectively. Intensity distributions of beam reflected from the surface of mirror and silicon bare wafer have been observed in a gaussian form. Experimental results show that focal position obtained by LD is shifted from one observed from surface scribed by laser about $80{\mu}m$. It is due to the difference of wavelength and each divergence of between LD and laser used for material process. It is confirmed that auto focusing control system through position calibration has operated steadily.

• 자동차안전학회지
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• 제14권2호
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• pp.90-95
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• 2022

Composite material is widely used in the automotive industries because it has excellent mechanical properties and is possible to reduce weight due to the low density. However, there is a new obstacle to meet environment regulation like Cu less or Cu free regulation for the friction material. Although it is strongly demanded, there are few research results about that unfortunately. Unless this problem is not solved properly, it is impossible to apply composite brake system to vehicle. In this paper, a new eco-friendly friction material for composite brake system is represented to respond these regulations. To do this, friction characteristics between existing low steel friction material and new eco-friendly friction material are verified to secure performances for brake system such as effect characteristic, fade characteristic and wear characteristic. And composite brake gets the equivalent or better performance compared to a low steel friction material. Finally, this result contributes to the study of major principles for the development of eco-friendly friction material in the future.

• 전기학회논문지P
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• 제65권3호
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• pp.224-234
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• 2016

This study developed the conductivity pattern of solid surface using laser direct pattern and compound polymer material technology. For development direct patterning system of solid surface, we used the laser power stabilizer, the dynamic focusing, 3D scanner S/W and the auto aligning techniques. Also For conductivity pattern, we are developed compound polymer material with additive by electro-less plating. These technologies are already used commercially. However operation and control integrated system for direct patterning of solid surface are not yet developed. The objective of this paper is to introduce the laser direct structuring for simple process improvement instead complex PCB process, and develop the operating stability and integration system. Also we implemented new application of laser direct structuring through sample manufacture.

• 한국자동차공학회논문집
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• 제15권1호
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• pp.171-176
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• 2007

An important challenging issue in the automotive industry is the light-weight, safe design and enhancement of crash response of an auto-body structures. These objectives lead to increasing adoption of high strength steel sheet for inner and outer auto-body members. This paper evaluates the dynamic tensile characteristics of high strength steel sheets, HS45R, TRIP60, DP60 and DP100, along the rolling direction and transverse direction. Static tensile tests were carried out at the strain rate of 0.003/sec using the static tensile machine (Instron 5583). Dynamic tensile tests were carried out at the range of strain rate from 0.1/sec to 200/sec using a high speed material testing machine developed. The tensile tests acquire stress-strain relation and strain rate sensitivity of each material. The experimental results show two important aspects for high strength steels: the flow stress increases as strain rate increases; the strain hardening decreases as the tensile stress increases. The experiments also produce interesting results that the elongation does not decrease even when the strain rate increases.

• International Journal of Automotive Technology
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• 제4권3호
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• pp.149-156
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• 2003

This paper is concerned with the energy absorption efficiency of auto-body side structures for the conventional steel and 60TRIP high strength steel. In order to evaluate the energy absorption efficiency, the dynamic crash analysis is carried out with the regulation of US-SINCAP. The analysis adopts the Johnson-Cook model for the dynamic material properties, which have been obtained from dynamic material tests. For the sake of the dynamic material properties, the analysis has been accurately peformed for the crashworthiness assesment. The analysis result provides deformed shapes, amounts of penetration and accelerations at several important points during crash. The result confirms that 60TRIP greatly improves the crashworthiness of the side members without sacrificing the weight and thus can be used for the light-weight design of an auto-body.