• 자동차안전학회지
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• 제11권4호
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• pp.57-62
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• 2019

The seat back frame of the vehicle is subjected to load on the passenger behavior. Because of steel material, it is necessary to optimize the frame considering lightweight and safety. In this paper, finite element analysis is used for the optimal design of the seat back frame. First, a lightweight material is applied to reduce the weight of the seat back frame. Secondly, the design position of the pipe part fastened in the seat back frame was selected by considering the strength against the load generated by the occupant. Third, the shape of the side frame was derived by performing the phase optimization analysis for the AFT load condition. And we have compared the initial model with the optimal model to verify the light weighting and safety. As a result, the optimal design model of the seat back frame satisfying the weight reduction and safety has been proposed.

• 한국자동차공학회논문집
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• 제21권2호
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• pp.104-113
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• 2013

New USNCAP has been carried out by NHTSA including front and side crash from MY2011. In this paper, test results for USNCAP Side crash were reviewed by statistical analysis. This review focused on side crash test results to investigate the effect of changes from new USNCAP side crash test protocol among 30 passenger cars. These results were summarized as followings. Total number of 5 star vehicles on the front seat dummy (16 vehicles, 53.3%) was slightly smaller than the rear seat's (17 vehicles, 56.7%) in MDB test. For the ES-2re dummy, chest injury, ie maximum rib deflection contributed to 66% in the mean value of $P_{joint}$. Pelvis injury was highly dependent upon performance up to 87% in the SID-IIs dummy cited on the rear seat in average $P_{joint}$. For Pole test, pelvis injury made contribution to the average performance to 83%. For standard deviation, it showed the largest value in the same body region as the mean value for each dummy. Overall front seat performance showed 14 vehicles, 44.6% with 5 star vehicles less than each MDB or Pole test result. This result showed that performances in MDB test were different pattern to Pole test on driver position. Number of 5star vehicles for overall side NCAP performance are 18 passenger cars (60%). Curtain airbag and driver thorax airbag were equipped in all test vehicles. One vehicle is equipped with thorax airbag in the rear seat. Results from two side tests considered as reliability problem, ie the cause for large standard deviation in side crash test. Consequently, the countermeasure for new USNCAP side crash test is essential to design the effective side structures for side collision and to control well dummy kinematics with curtain and thorax airbag in order to reduce chest and pelvis injuries.

• 한국자동차공학회논문집
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• 제14권5호
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• pp.107-114
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• 2006

This paper investigates the radiating source of electro-magnetic waves in the cabin of automobile with spark ignition engine. Front seats are very close to the engine room where electro-magnetic waves are expected to be radiating. But front seat area is believed to be a blind zone, which is not affected by radiating electro-magnetic waves, because a bulk board and floor board shield the front seat area. The level and frequency spectrum of electro-magnetic waves are measured at the passenger seat and the engine room. The measured frequency range is $145{\sim}365MHz$. As a results, the level of the electro-magnetic waves of automatic transmission vehicle is greater than -82dBm. The shapes of frequency spectrum of both engine room and passenger seat are look alike. But the level of electro-magnetic waves of manual transmission vehicle is less than -82dBm and the shapes of frequency spectrum of engine room and passenger seat are different to each other. From these results, we can say that any mal-function caused by electro-magnetic waves in the automobile cabin are only possible for automatic transmission vehicle. Also, it is believed that the radiating source of electro-magnetic waves is inside the vehicle. Thus, based on the transmission line theory, this paper presumably concludes that the cables which connect all the components inside a automatic transmission vehicle must be a radiating source of electro-magnetic waves in the cabin.

• 소음진동
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• 제11권1호
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• pp.76-81
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• 2001

This paper addresses experimental results carried out to investigate the transmission of seat vibration to the head for Korean. Vertical seat vibration in the frequency range of 0.5-30 Hz was applied to a seated Korean male subject. To examine the intra-variable effects on transmissibility, five different postures and three different vibration excitation levels were considered. The applied acceleration and head accelerations of the seated subject were measured simultaneously by using a 6-axes bite-bar. Detailed experimental results of measured transmissibilities are illustrated for each posture and/or vibration excitation level, and they were compared to an International Standard. They are found to allow the identification of dynamic characteristics of Korean seated body for various reat vibration environments. Furthermore, they are expected to be very useful in designing new seats for automotive and railway vehicles and in improving their vibration ride quality.

• 한국정밀공학회지
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• 제26권3호
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• pp.88-97
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• 2009

The vacuum die casting techniques can diminish the porosity of products and provide better surface appearance by the ordinary high pressure die casting process. The vacuum system can also reduce the cold laps in the die casting process and minimize the overflow pockets of the die. The vacuum system does not need high pressures to die cast compared to the ordinary die casting process, and so enables die casting of large parts for a given machine size. Parts made by the vacuum system have higher strength and more elongation than parts made by the ordinary die casting systems. In this paper, we designed and produced the Magnesium seat frames using the vacuum die casting processes. The new Magnesium seat frame was designed to satisfy safety regulations. Some safety test procedures of the seat frame were simulated by the finite element method. We obtained 10% weight reduction by design modification of seat frames compared to the current model. Flow simulations were carried out to minimize the trial and error in producing the parts. The die casted parts using vacuum systems resulted in better mechanical characteristics and no defects compared to those without vacuum systems.

• 한국기계가공학회지
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• 제16권3호
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• pp.24-29
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• 2017

In this study, a seat cross member was fabricated by optimizing the resin transfer molding processing of CFRP (Carbon Fiber Reinforced Plastics) materials. This seat cross member is used in automotive underbody parts and provides side impact support. The seat cross was manufactured via vacuum resin transfer molding. The process included 1min of resin injection, 8 mins of heating, and 1 min of cooling, for a total molding time of 10mins. Tensile test results showed an average breaking load of 21.50kN, a tensile strength of 404 MPa, and an elastic modulus of 46.2 GPa. As a result, the CFRP seat cross provides the same strength as a similar steel part, but weighs 42% less.

• 한국생산제조학회지
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• 제18권5호
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• pp.477-482
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• 2009

This study analyzes the result with dynamic simulation about deformation according to time when a car impacts bollard. These results are shown as followings. The maximum deformation is shown at the lower part of front grass in case of the impact of front or passenger seat but this deformation is shown at the lower part of rear bumper in case of double impact. The maximum equivalent stress is shown at the upper part by the side grass of driver seat at the elapsed time of 0.00075 second after impact in case of the impact of front or passenger seat but this deformation is shown at the front bonnet at the elapsed time of 0.004 second after the additional impact in case of double impact. The maximum total deformation or equivalent stress is shown nearly same in case of the impact of front or passenger seat. But the value of this deformation or equivalent stress in case of the impact of front or passenger seat is shown with 2 times or more than 17% respectively as this value in case of double impact.

• 한국자동차공학회논문집
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• 제2권1호
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• pp.26-37
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• 1994

In this study, flow of a model intake port/valve system is analyzed by using low Reynolds number $k-{\varepsilon}$ model. Discharge coefficient was obtained from computational results for the various cases of valve lifts. Discharge coefficient becomes maximum when the valve lift is 20mm, and does not increase or decrease in proportional to valve lift. Most of pressure drop and production of turbulent kinetic energy occur at the edge points of the valve and the valve seat Thus, in order to improve discharge coefficient, rounding of edge points in valve and valve seat is recommended. As valve lift is increased, the velocity of the intake jet in the valve passage decreases, and the direction of the jet is more inclined toward the valve seat.

• 한국자동차공학회논문집
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• 제9권3호
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• pp.42-50
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• 2001

In this paper, the effects of scale formation in engine water jacket upon the thermal durability of engine itself and its component parts were studied. To understand the effect of quality of water, a full load engine endurance test for 50 hours was carried out with not-treated underground water. The followings were found through the tested engine inspection after the endurance test; 1-2 mm thick scale formation in the engine water jacket, valve seat wear, piston top land scuffing, piston pin stick, and cylinder bore scuffing in siamese area. In order to understand the causes of above test results, the heat rejection rate to coolant, the metal surface temperature of combustion chamber, and the oil and exhaust gas temperatures were measured and analyzed. The scale formed in the engine water jacket played a role as thermal insulator. The scale formed in the engine reduced the heat rejection rate to coolant and it caused to increase the metal surface temperature. The reduced heat rejection rate to coolant increased the heat rejection rate to oil and exhaust gas and increased the oil and exhaust gas temperature. Also, the reasons of valve seat wear, piston top land scuffing and cylinder bore scuffing, and piston pin stick quantitatively analyzed in this paper.

• 한국자동차공학회논문집
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• 제22권3호
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• pp.203-209
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• 2014

The rear center-hinge bracket is designed for supporting and folding the rear-seat backrest. This bracket needs to be strong enough to be able to rigidly hold the rear-seat backrest and to withstand luggage loads from the car trunk that are generated when a vehicle is driving on the roads. Particularly, current accident studies report that many serious occupant injuries occurred when the rear-seat back easily folded inward toward the car interior, driven by the luggage loads in the trunk. Given this fact, the robust design of the rear center-hinge bracket that mainly supports the rear backrest has become more important for providing customer safety and preventing high warranty and durability problems. However, none of the studies have emphasized its significant role and considered its robust optimization. Therefore, this paper presents how the hinge-bracket design is optimized based on an application of the finite-element method coupled with the parameter design using Taguchi's design experiment. Finally, Taguchi method's application optimizes a robust center-hinge bracket that shows more rigid performance although it has lighter weight and thinner thickness.