• Macromolecular Research
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• v.17 no.11
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• pp.886-893
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• 2009

Surface modifications using a radio frequency Ar-plasma treatment were performed on a polypropylene (PP) blend used for automotive bumper fascia. The surface characterization and morphology were examined. With increasing aging time, there was an increase in wettability, oxygen containing polar functional groups (i.e., C-O, C=O and O-C=O) due to oxidation, the amount of tale, and bearing depth and roughness on the PP surface, while there was a decrease in the number of hydrocarbon groups (i.e., C-C and C-H). AFM indicated that the Ar-plasma-treatment on a PP blend surface transforms the wholly annular surface into a locally dimpled surface, leading to an improvement in wettability. SEM showed that the PP layer observed in the non-plasma-treated sample was removed after the Ar-plasma treatment and the rubber particles were exposed to the surface. The observed surface characterization and morphologies are responsible for the improved wettability and interfacial adhesion between the PP blend substrate and bumper coating layers.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.237-243
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• 2005

To design ship channel is one of important factors for planning and developing a port. Bends in channel should be avoided if possible, but the channel should be widened, if channel bend is unavoided, to account widened path of a ship in bend for the safe passage of a ship. In this study, Variable Bumper Area(VBA) model is applied to determine ship channel width in bend and channel-bend geometry. The result of this study shows that the width of a channel in bend may be designed as wide as the width in straight lane provided the angle of deflection is less than 30 degree, should be widened for 60degree deflection based on the length of the largest ship using the channel and the angle of deflection.

• Journal of Navigation and Port Research
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• v.29 no.8 s.104
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• pp.693-699
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• 2005

To design ship channels is one of important factors for planning and developing a port. Bends in channels should be avoided if possible, but the channel should be widened, if channel bend is unavoidable, considering the swept path of a ship for safe passage. In this study, Variable Bumper Area(VBA) model is applied to determine the channel widths in bends. The result of this study shows that the width of the bend may be designed as nearly same size of that in straight channel in case that the angle of deflection is less than 30 degrees, and that of the bend with 60 degrees deflection should be widened based on the length of the largest ship using the channel and the angle of deflection.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.5
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• pp.57-68
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• 2014

MSRDS(Microsoft Robotics Developer Studio), the robot simulation platform provides the simulation robots and environments enabling to the basic robot programming without hardware robots. In this paper, we carry the maze escaping problems to compare and analyze the performance of LRF, bumper, IR, and sonar sensor with the same condition on MSRDS(Microsoft Robotics Developer Studio) environment. To evaluate the performance of sensors, we program the simulation environments with same conditions for all sensors. We could find that the LRF sensor had the highest performance and the bumper sensor has the lowest performance on the travel time, the number of turning, and the number of collisions. It was also confirmed that IR sensor and sonar sensor had lower performance than LRF sensor on the number of turning.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1515-1522
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• 2011

This paper proposed the finite element analysis technique for improving the correleration accuracy between FEA and test on a pedestrian lower legform impact. Europe has been evaluating the bumper pedestrian impact by Euro-NCAP, and it will also be applied in a domestic area by K-NCAP in 2013. By using the compression test result of bending resisting stiffener, a pedestrian bumper modeling guide was presented by analayzing the force-displacement curve of stiffener. And by using the sensor measurement results in car pedestrian test, pedestrian impact behavior was analyzed between test and finite element analysis result. Finally, the finite element analysis guide for a pedestrian bumper impact was presented to improve the correleration accuracy.

• Journal of the Korea Convergence Society
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• v.10 no.8
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• pp.159-164
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• 2019

The front bumper of bobsleigh is mounted to alleviate the impact, but the air resistance to the bobsleigh depends on the body shape positioned in front. This study was conducted the flow analyses about three kinds of bobsleigh configurations. Models B and C with the sharp type of the front can reduce the air resistance than model A with the round type of the front. And the type that the back of the bumper narrows can generate a flow smoother than the one widening. It is thought that the results of this study can be devoted at ensuring the body design to reduce the flow resistance most at bobsleigh. As the design data with the durability of bobsleigh obtained on the basis of this study result are utilized, the esthetic sense can be shown by being grafted onto the machine or structure at real life.

• Earthquakes and Structures
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• v.23 no.2
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• pp.129-138
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• 2022

One of the objectives to prevent building pounding between two adjacentstructures is to considerseparation distance or decrease relative displacement during seismic excitation. Although the majority of building codes around the world have basically suggested some equations or approximately recommended various distances between structuresto avoid pounding hazard, but a lot of reportsin zone of pounding have obviously shown thatsafety situation or economic consideration are not always provided due to the collisions between buildings and the cost of land, respectively. For this purpose, a dynamic MDOF model by having base isolation system is numerically considered and using various earthquake records, relative displacements are mathematically investigated. Different equations to determine the value of damping ratio are collected and the results of evaluations are listed for comparison among them to present a new equation for determination of impact damping ratio. Presented equation is depends significantly on impact velocity before and after impact based on artificial neural network, which the accuracy of them is investigated and also confirmed. In order to select the optimum equation, hysteresisloop of impact between base of building and rubber bumper is considered and compared with the hysteresis loop of each impact, calculated by different equations. Finally, using representative equation, the effect of thickness, number and stiffness of rubber bumpers are numerically investigated. The results of analysis indicate that stiffness and number of bumpers have significantly affected in zone of impact force while the thickness of bumpers have not shown significant influence to calculate impact force during earthquake. For instance, increasing the number of bumpers, gap size between structures and also the value of stiffness is caused to decrease impact force between models. The final evaluation demonstrates that bumpers are able to decrease peak lateral displacement of top story during impact.

• Clean Technology
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• v.30 no.3
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• pp.239-247
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• 2024

The removal of volatile organic compounds (VOCs) from spent polypropylene (PP) sourced from the bumpers and interiors of used cars was carried out by using high-temperature supercritical carbon dioxide (scCO₂) extraction. The recycled polymers from the bumpers and interiors contained other additives beside PP such as polyethylene (PE), talc, and carbon black, which modified the properties of PP. The crystallinity of the recycled bumper and interior PP was significantly lower than that of the virgin PP pellet. The decomposition temperatures of the recycled bumper and interior PP was slightly higher than that of the virgin PP pellet, while the melting and crystallization points were slightly lower. The effect of process conditions on VOC removal was studied by varying the time (2 ~ 720 min), pressure (6.4 ~ 14 MPa), and temperature (298 ~ 473 K). Since VOC removal at 2 min produced satisfying results, times below 2 min (10 ~ 120 s) were also studied. The main goal of scCO₂ extraction was to reduce the xylene content, as the xylene content of the recycled bumpers was higher than the allowable limit. A temperature above 373 K was needed to remove the xylene from the waste PP samples. The optimum condition for VOC removal from bumper waste was determined to be 433 K, 8 MPa, and 60 s. The car interior waste had VOC content within the allowable limit, so no further treatment was needed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.6
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• pp.535-543
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• 2009

This paper describes a design for RFID(Radio Frequency Identification) tag antenna using license plate attached the vehicle bumper in 900 MHz band. The proposed tag antenna size which is located on upper center position of a vehicle license plate is 162.5${\times}$40${\times}$1 mm$^3$. A resonant frequency of design antenna and the bandwidth which has return loss of -10 dB below are 900 MHz and about 720 MHz(640${\sim}$1,360 MHz), respectively. The commercial chip impedance considered on design was 16- j131 ${\Omega}$ and the complex conjugate impedance of chip was used as input impedance of tag antenna. The measured return loss and radiation pattern were agreed well with the calculated results. The measured readable range of the proposed tag antenna designed on only the vehicle license plate was 11.5 m. Moreover, its range of the fabricated tag antenna that the license plate and the vehicle bumper were fixed by volt and nut was observed 10.4 m. These measured readable range showed about 5 m above far distance more than the average readable range of commercial tag antenna.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.193-194
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• 2008