• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.12
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• pp.1549-1556
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• 2011

Tensile and creep tests were performed at various temperatures to investigate the mechanical properties of plastics used in automotive instrument panels. Mechanical properties such as Young's modulus and Poisson's ratios changed markedly with the test temperature. Three-point bending creep tests were performed for three kinds of plastics under four loading conditions. Coefficients in the time-hardening power law creep equation were obtained from the experiment, and the creep behavior was represented by a simple expression. The results of finite element creep analysis showed good agreement with the experimental results, while the difference between the numerical and experimental results increased with the load.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.4
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• pp.651-656
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• 2019

This paper is a study on the structure system and implementation of cantilever actuator for decontamination. There are many kinds of exterior materials that attach to the exterior walls of a building. Glass, in particular, can be contaminated in a short period of time due to external exposure. The pollutants like this damage the appearance of a building. It can also cause health problems for users, and dust attached to solar panels creates problems that greatly reduce the power generation of solar panels. In order to remove such contaminants, professional workers usually remove contaminants attached to the outer walls. However, even with stability, accidents are often caused by a number of unexpected variables that occur in the field. Thus, to overcome these shortcomings, the cantilever actuator structure system was proposed. The system was designed through research. Then, we made a cantilever actuator and checked its operability. Finally, the effectiveness of the cantilever actuator was reviewed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.200-207
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• 2016

The automotive seat is an important component that moves in sync with the driver and is actively being developed with various new functions. The aim of this work is to develop a lightweight seat cushion extension module using a lightweight material. To this end, a structural strength analysis, vertical strength test, and durability test were conducted. In the structural analysis, the maximum value of deformation under vertical load was 4.98 mm at the front of the upper panel. The maximum stress was approximately 105 MPa, which occurred at the point of contact between the upper and lower panels of the module. The vertical strength test showed a maximum vertical deformation of 5.31 mm under a vertical load, which differed from the analysis results by approximately 6.45%. The structural safety of the product was verified by the fact that it showed no harmful deformation or damage during operation after the vertical strength test and a durability test for 20,000 cycles. Furthermore, the use of engineering plastics made it possible to reduce the weight by approximately 30% compared to existing products. The lack of damage after tests verified the passenger safety, strength, and rigidity of the product. The results are expected to be applied for improving environmental and fuel efficiency regulations and preventing accidents due to driver fatigue. The applications of this module could be expanded various types of vehicles, as well as other industries in which eco-friendly and lightweight materials are used.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.3
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• pp.204-210
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• 2004

Most auto-body members fabricated by the sheet metal forming process. During this process the thickness and material properties of the sheet metal are changed with the residual stress and plastic strain. This paper deals with the material properties of the sheet metal at the high strain rate considering the pre-strain effect. Specimens are selected from sheet metals for outer panels and inner members, such as SPCEN, SPRC45E, SPRC35R and EZNCD. The specimens are prepared with the pre-strain of 2, 5 and 10 % by tensile elongation in Instron 5583, which could be equivalent to the plastic strain in sheet metal forming. High speed tensile tests are then carried out with the pre-stained specimens at the strain rate of 1 to 100/sec. The experimental result informs that the material properties are noticeably influenced by the pre-strain when the yield stress of the specimens is moderate as SPCEN, SPRC35R and EZNCD. The result also demonstrates that the ultimate tensile strength as well as the yield stress is increased as the amount of the pre-strain is increased.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.12
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• pp.24-29
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• 2021

Recently, owing to the high demand for eco-friendly cars in the automotive industry, noise and vibrations have become major challenges. The use of laminated damping steel is increasing in response to these demands. Laminated damping steel is primarily used in sound insulation plates. The vibration energy is converted into thermal energy due to the viscoelastic resin being located between two steel sheets and being able to damp the vibrations when an external force, such as, noise or vibration is applied to the steel plate. Laminated damping steel is chiefly applied to dash panels in automotive body parts, and because of its structure, junction technology for bonding with other components is necessary. However, there has not been sufficient research conducted on junctions. In this study, regardless of the electrode shape, in the range of 4.0 ~ 8.0 kA welding current, the same welding force and welding time were applied which were 2.8 kN and 200 m/s (12 cycles) and the tensile shear load and nugget size were analyzed after the resistance spot welding between different materials of laminated damping steel with a thickness of 1.035 mm. The results show that in the range of 5 ~ 8 kA welding current, 1.035 mm laminated damping steel meets the MS181-15 standard, which is the technical standard of Hyundai-Kia Motors.

• Journal of Information Technology Services
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• v.17 no.3
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• pp.53-61
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• 2018

In this paper, we propose a car sealing monitoring system combined with ICT Technology. The automobile sealer is an adhesive used to bond inner and outer panels of doors, hoods and trunks of an automobile body. The proposed car sealer monitoring system is a system that can accurately and automatically inspect the condition of the automobile sealer coating process in the general often factory production line where the lighting change is very severe. The sealer inspection module checks the state of the applied sealer using an area scan camera. The vision inspection algorithm is adaptive to various lighting environments to determine whether the sealer is defective or not. The captured images and test results are configured to send the task results to the task manager in real-time as a smartphone app. Vision inspection algorithms in the plant outdoors are very vulnerable to time-varying external light sources and by configuring a monitoring system based on smart mobile equipment, it is possible to perform production monitoring regardless of time and place. The applicability of this method was verified by applying it to an actual automotive sealer application process.

• Transactions of Materials Processing
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• v.20 no.2
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• pp.99-103
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• 2011

Many parameters influence the frictional behavior of steel sheet during stamping. The contact pressure between a die and a sheet during stamping is one of them. Thus, this parameter is investigated for high strength steel (HSS) sheets, which are widely used for auto body panels due to their potential for weight reduction. Since HSS extend the limits of contact pressure for mild steel, the effect of this parameter on friction cannot be ignored. To investigate the influence of contact pressure on the frictional behavior of steel sheets, a flat type of friction test was conducted on three different steel sheets under various contact pressures. For bare steel sheets, the curve representing the relationship between contact pressure and friction coefficient exhibits a U shape. Coated steel sheets show a similar tendency except at low contact pressure. For these materials, when the contact pressure is very low, the friction coefficient slightly increases with pressure before it starts to decrease. The test results show that the effect of contact pressure on frictional behavior of steel sheet is not negligible even for contact pressures that are lower than the strength of HSS sheet.

• Transactions of Materials Processing
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• v.20 no.7
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• pp.512-517
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• 2011

TRB(Tailor Rolled Blank) is an emerging manufacturing technology by which engineers are able to change blank thickness continuously within a sheet metal. TRB door inner panels with required larger thicknesses can be used to support localized high loads. In this study, the aluminum alloy 5J32 TRB sheet is used for a door inner panel application. The TRB material properties were varied by using three heat treatment conditions. In order to predict the failure of the aluminum TRB during simulation, the forming limit diagram, which is used in sheet metal forming analysis to determine the criterion for failure, was investigated. Full-field photogrammetric measurement of the TRB deformation was performed with an ARAMIS 3D system. A FE model of the door inner panel was created using Autoform software. The material properties obtained from the tensile tests were used in the numerical model to simulate the door inner of AA 5J32 for each heat treatment condition. After finite element analysis for the evaluation of formability, a prototype front door panel was manufactured using a hydraulic press.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.1
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• pp.79-87
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• 1996

SMC(Sheet Molding Compound) is made of unsaturated polyester resin and other additives reinforced with randomly distributed chopped fiberglass strands. Because of its higher stiffness per unit mass, SMC was used as a substitute for steel for automotive steel outer panels. Thus, understanding of flow characteristics during fabrication of SMC is of importance since the formation of weld line depends on material flow. In the present study, SMC compression molding simulations in the flat and T-shape molds were accomplished. During simulations, the preferential the preferential flow occurred at the low mold closing speed while plug flow was observed for the higher mold closing speed. When the preferential flow was observed, the weld line was seen at the final stage. For simulations, rigid-viscoplastic finite element method was applied. Self-contact algorithm was also applied in order to predict the formation of the weld line. Simulation results were compared to the experimental results available in the literature.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.12
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• pp.82-90
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• 2019

This analysis demonstrates the effective removal of heat generated from a solar panel's output degradation factor solar cells (the solar panel's output deterioration factor), and solves the problems of oxidation and corrosion in existing metal heat sinks. The heat-dissipating test specimen was prepared using carbon materials; then, its thermal conductivity and its effectiveness in reducing temperatures were studied using heat transfer numerical analysis. As a result, the test specimen of the 30g/㎡ basis weight containing 80% of carbon fiber impregnated with carbon ink showed the highest thermal conductivity 6.96 W/(m K). This is because the surface that directly contacted the solar panel had almost no pores, and the conduction of heat to the panels appeared to be active. In addition, a large surface area was exposed to the atmosphere, which is considered advantageous in heat dissipation. Finally, numerical analysis confirmed the temperature reduction effectiveness of 2.18℃ in a solar panel and 1.08℃ in a solar cell, depending on the application of heat dissipating materials.