• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.10
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• pp.44-49
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• 2021

Seats in autonomous vehicles must be able to rotate to fully utilize the interior space. Generally, ultra-high strength steel is used for the rotation module because it should have high strength and high rigidity. In addition, the rotating parts are difficult to form because they have complex shapes. In this study, the upper plate of the rotating module, whose complex shape makes it difficult to form, was formed by applying the hot stamping method. The drawing method and the form-drawing method, which are generally used to form components of complex shapes, were compared. We showed that the form-drawing method increased the degree of freedom of the material flow to improve the formability, thus enabling the forming of the plate. In addition, the die and blank shapes were found to be important factors in determining the success of the hot stamping. The validity of the analysis results was confirmed through forming analysis and experiments.

• Fire Science and Engineering
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• v.24 no.2
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• pp.82-88
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• 2010

In this study, we have performed several tests for composite plastic materials to be applied on interior materials of a vehicle to identify their combustion characteristics using cone calorimeter, smoke density chamber and toxicity index chamber. We have prepared a total of 12 samples for 4 major parts of a vehicle wherein each major part has 3 different materials. The results of cone calorimeter test showed ignition time of PVC sheet and PVC leather were 2s. The 8 samples showed under less than 10s of ignition time. The sample comprising Nylon and PE had the biggest maximum heat release rate of 635 $kW/m^2$. The sample comprising Rubber showed the smallest maximum heat release rate but with the biggest total heat release. The results of smoke density chamber test showed the sample that is made up with Rubber had the biggest specific optical smoke density. The sample comprising PVC leather and PUR showed the biggest VOF4 which enables the initial smoke production. The results of toxicity index test showed that all samples contained carbon dioxide content exceeding its lethal concentration. The sample comprising PVC showed high content of hydrogen chloride and hydrogen bromide. The PVC sheet showed the biggest toxicity index calculated by using lethal concentration and test results. Toxicity index of all sample wes over 1.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.12
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• pp.1585-1590
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• 2012

Engineering plastics are used in instrument panels, interior trim, and other vehicle applications, and the thermomechanical behaviors of plastic materials are strongly influenced by many environmental factors such as temperature, sunlight, and rain. As the material properties change, the mechanical parts create unexpected noise. In this study, the dynamic mechanical property changes of plastics used in automobiles are measured to investigate the temperature effects. Viscoelastic properties such as the glass transition temperature and storage modulus and loss factor under temperature and frequency sweeps were measured. The data were compared with the original ones before aging to analyze the behavior changes. It was found that as the temperature increased, the storage modulus decreased and the loss factor increased slightly.

• Analytical Science and Technology
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• v.24 no.4
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• pp.282-289
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• 2011

Rapid screening method for the determination of the emissions of pollutants from vehicle interior parts and materials have been developed as ISO 12219-2 which is using bag and based on a static condition. The method was not controlled humidity in the test bag, so it is not suitable test method for formaldehyde emission test which is highly related to humidity condition. In this study, possibility of control humidity in the static test bag by adding extra water and the effect of humidity condition for formaldehyde emissions have been investigated. The relative humidity in the test bag was affected not only amount of water added also material of test bag and test specimen. The emission intensity of formaldehyde was increased according to increasing relative humidity in test bag. But excessively supplied water was condensed on the inner surface of test bag and surface of sample specimen that were sorption formaldehyde and were reduced its emission intensity.