• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2546-2551
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• 2007

Weather Strip(W/S) is a rubber part to proof water, sound and dust for opening and shutting devices including vehicle doors. And it requires high dimension precision and durability to proof water, noise, vibration and etc. But ironically it itself makes some wind noise because of some protuberance with glasses. The air flow analysis of door part of vehicle makes it possible to calculate and find out the cause of wind noise. In previous analysis, we focus on the numerical air flow analysis of the automobile side part. We do 2D-C.F.D first and 3D second. Through simulations, we can calculate the amount of sound pressure level at the glass run and find out the effects of glass run to make wind noise. Finally we can improve shape of glass run to reduce wind noise although it is small amounts of sound pressure reduction compared with total vehicle noise level.

• Journal of Korean Institute of Industrial Engineers
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• v.42 no.5
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• pp.360-369
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• 2016

This study attempted to identify the effect of the panel stiffness on the customers' affect, which was not addressed in the research field of affective engineering. For this, this study derived four affects related to the panel stiffness from literature and pre-experiment : hardness, deform consistency, thickness and satisfaction and prepared a questionnaire to evaluate the affects of the panel. In the experiment, 54 adults in the age of 20~50 participated and evaluated the affects of hood, front and rear door for nine full size and luxury sedans by pressing the panels with their hands. As results, participants' affect for the panels were significantly different depending on the force-deflection curves of them, and the subjects' satisfaction of the panels increased as the slope of the curve (stiffness) increases. In addition, it was found that the subjects evaluated the panel with the pressing force up to 14kgf. The findings of the study can be used to increase and control the affective quality of exterior panels on passenger cars.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.909-917
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• 2007

Recently the trend of automobile industry is that IQS evaluation index against a sensitivity quality is increasing. To reduce rattle noise due to speaker sound at low frequencies, it is required the advanced investigation of a package tray panel and a door module panel. This paper optimized the design parameters of package tray panel according to the theoretical background about robust design and suggested the design guideline for resonance avoidance and the reduction of vibrational sensitivity considering the excitation frequency of woofer speaker. In addition, it is suggested the design guideline of a door module panel through the sensitivity analysis in case of the speaker excitation. Finally, the design factor analysis of the quality deviation of a mother-car will make it possible to guarantee the stable characteristics of vehicle vibration in the early stage of vehicle development. These improvements can lead to shortening the time needed to develop better vehicles.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.8
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• pp.673-682
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• 2007

Recently the trend of automobile industry is that IQS evaluation index against a sensitivity quality is increasing. To reduce rattle noise due to speaker sound at low frequencies, it is required the advanced technology analysis process of body structure. This paper optimized the design parameters of package tray panel according to the theoretical background about robust design and suggested the design guideline for resonance avoidance and the reduction of vibrational sensitivity considering the excitation frequency of woofer speaker. And this paper described the design process of a door module panel through the sensitivity analysis in case of the door speaker excitation. Finally, the analysis of the quality deviation using mother car is suggested to guarantee the stable characteristics of vehicle vibration in the early stage of vehicle development. These improvements can lead to shortening the time needed to develop better vehicles.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.9 s.186
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• pp.134-141
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• 2006

Surface deflections have a great effect on the external appearance of automobiles. Usually, they are occurred on large flat panels containing sudden shape changes and of very small size about $\pm$30$\sim$300$\mu$m. Since the current numerical method is not sufficient for predicting these defects, the correction of these defects still depends on trial and error, which requires a great deal of time and expense. Consequently, developing the numerical method to predict and prevent these defects is very important far improving cosmetic surface qualities. In this study, an evaluation system that can analyze surface deflections using numerical simulation and a visualization system are reported. To calculate the surface deflections numerically, robust algorithms and simulation methodologies are suggested and to visualize them quantitatively, the curvature variation algorithm is proposed. To verify the developed systems, the experimental die of the handle portion of exterior door is analyzed. The results showed that the experimental and simulational visualization are in good agreement. Compensation methods to correct the surface deflections are also tested. The evaluation system proposed in this paper could be used to predict and minimize the occurrence of surface deflections in die manufacturing.

• Design & Manufacturing
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• v.17 no.2
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• pp.47-54
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• 2023

The research direction of the automobile industry worldwide is speeding up research to improve fuel efficiency through weight reduction as the weight of automobiles increases due to environmental problems, convenience demands, and safety problems. As a way to solve weight reduction, there is a method of improving mechanical properties by improving the development and manufacturing method of lightweight materials with replaceable mechanical properties. Therefore, research on the molding and processing technology of aluminum, which is a lightweight material, is being actively conducted. In this study, aluminum material was applied. By using Autoform S/W, a press forming analysis program, the blank holding force, mold die R, and bead restraint force were selected in three levels, respectively, and the results and optimization of formability and shape freezing were carried out. In this study, aluminum material was applied. By using Autoform S/W, a press molding analysis program, the blank holding force, mold die R, and bead restraint force were selected in three levels, respectively, and the results and optimization of formability and shape freezing were carried out. The optimized results were confirmed by comparative analysis of formability and Spring Back. As a result of the experiment, it was possible to confirm the result value of the Spring Back of the final product according to the tensile change of the material.

• Journal of the Korea Safety Management & Science
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• v.14 no.2
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• pp.123-136
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• 2012

The validity of the results from observational methods such as RULA, REBA, OWAS has been one of major concerns due to their subjective characteristics in determining the posture of interests. There have been many studies regarding validity of the results from each checklist. However, most studies provided only fragmentary rather than comprehensive results in nature. This study specifically tried to analyze consistency of novice user based on intra-observer consistency and sensitivity of industrial types during MSDs(Musculoskekltal Disorders) evaluation with major checklists. In this study, twenty two novice subjects were participated to conduct MSDs evaluation for the forty five jobs from three types of industries(automobile, electronics, hospital). The main results for this study were summarized as follows; 1) The action level based on RULA was always higher than that from REBA and OWAS for all three types of industries., 2) The order of consistency from novice users was OWAS(72.7%(kappa=0.57)) RULA(54.3%(kappa=0.41)), REBA(41.0%(kappa=0.34))., 3) The percentage of agreement between 2nd and 3rd trials was higher than those between 1st and 2nd trials and between 1st and 3rd trials irrespective of industrial types during using RULA and REBA., 4) The average score of automobile industry was higher than those of hospital and electronics industries., 5) The types of jobs associated with five body parts(A1(Front), A2(Interior), A3(Rear), A4(Lower), A5(Door)) in automobile industry showed statistically significant differences in terms of MSDs scores for the body parts considered in each checklists.

• Journal of the Korea Safety Management & Science
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• v.13 no.2
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• pp.83-90
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• 2011

It has been very important to have an exact evaluation for risk factors in order to prevent WMSDs(Work-related Musculoskeletal Disorders). However, most WMSDs evaluation methods have always been some problems of possibilities associated with subjective evaluation. Therefore, this study tried to conduct a sort of usability analysis on three major evaluation methods(OWAS, RULA, REBA). Specifically, major subjects in the study consisted of three parts as follows; comparison of the results between experienced and inexperienced observers, analysis for the consistency of the results in terms of different evaluation times, and analysis for the consistency of the results in terms of different job characteristics(based on the part of the automobile). The results of the study were summarized as follows; 1) There was statistically significant difference of the results by RULA and by REBA between experienced and inexperienced observers. This might be due to the fact that experienced observers have had better ability to detect the important working posture during evaluation. However, the results by OWAS did not give any significantly different results between experienced and inexperienced observers, 2) All three checklists applied by experienced subjects did not show any single result significantly different in terms of different evaluation times. This might have to do with high intra-observer reliability from some of previous studies, 3) The five parts of an automobile were selected as five major jobs with different job characteristics in the automobile industry. Specifically, they were door part, front part(hood, etc.), inside part(dash board, seats, etc.), rear part(trunk etc.), and bottom part. All three methods did not show any significant differences for the results from each observers. Further study on this subject would eventually provide a sophisticated evaluating guidelines for WMSDs regarding determination of observer-specific evaluation, identification of repetitive number of evaluations for stable results for each checklist, determination of job-specific evaluation methods, and so on.

• Design & Manufacturing
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• v.9 no.1
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• pp.5-8
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• 2015

The company Daewoo Precision Industries imported fine blanking press of 40 tons from Switzerland with fine blanking tool in order to produce the fuse part of bomb in 1978 at first in Korea. About 1985 the first fine blanking tool for producing the door lock parts was manufactured in the company Gold Star (now LG). And then this technology was grown up with the growth of automobile industries in Korea. Now 31 companies are closely related to the fine blanking technology and there are total 146 fine blanking presses in Korea. The developments of fine blanking technology in industries have been oriented to the production of precise fine blanking parts, the reduction of die roll height on fine blanking parts, the production of complex fine blanking parts with progressive fine blanking tool including forming and forging technology, the production of high-strength steel fine blanking parts and so on. Some R&D activities in KITECH were introduced.

• Journal of Mechanical Science and Technology
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• v.17 no.4
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• pp.590-598
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• 2003

A computational aero-acoustic (CAA) method is used to predict the tonal noise generated from a cavity of automobile door seals or gaps at low flow Mach numbers (A$\_$$\infty$/=0.077 and 0.147) In the present method, the acoustically perturbed Euler equations are solved with the acoustic source term obtained from the unsteady incompressible Navier-Stokes calculations of the cavity flow in self-sustained oscillations. The aerodynamic and acoustic fields are computed for the Reynolds numbers based on the displacement thickness, Re$\_$$\delta$*/=850 and 1620 and their fundamental mode characteristics are investigated. The present method is also verified with the experimentally measured sound pressure level (SPL) spectra.