• The Journal of the Convergence on Culture Technology
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• v.10 no.6
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• pp.613-618
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• 2024

This study aimed to derive the optimal mixing ratio that secures the required performance of the road body(unconfined compressive strength: 0.44 MPa based on 28 days of curing) by applying soil stabilizer utilizing recycled resources and the in-situ soil that cannot be applied to the road body. To this end, the unconfined compressive strength was measured for three mixing ratios of soil stabilizer (80 kg, 100 kg, and 120 kg per 1m³) at 3, 7, 14, and 28 days of curing. As a result of measuring the unconfined compressive strength by curing day and mixing ratio, it was confirmed that the unconfined compressive strength increased as the mixing ratio of soil stabilizer utilizing recycled resources increased. It was confirmed that more than 100 kg of soil stabilizer utilizing recycled resources per 1m³ should be mixed to satisfy the required performance of the road body.

• Journal of the Ergonomics Society of Korea
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• v.30 no.4
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• pp.495-501
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• 2011

The objective of this study was to evaluate the convenience of the tractor seatbelt. We selected four healthy men as subjects. We measured their body pressure and examined the comfort of the seatbelt, while driving 50m on three different types of agricultural road with two types of seatbelts: automatic and manual. As results, when they used manual seatbelt, subjective uncomfortable rate was much higher than the automatic seatbelt on all types of road. Especially, body pressure was undistributed while using manual seatbelt on rough road.

• Journal of the Korea Institute of Military Science and Technology
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• v.3 no.2
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• pp.15-22
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• 2000

Shock and vibration characteristics of a tractor-trailer type vehicle system with air suspension and air coupler running on a single bump road are investigated. The vehicle system is modelled and solved to two types of models, i.e. rigid-multi-body and flexible-multi-body model, by ADAMS and NASTRAN software. And the shock impulse is given by a single bump model on the road. When the analysis results of the rigid-multi-body model is compared with those of the flexible-multi-body model, it is revealed that the vibration and accelerations of the latter model are more repetitive and larger than the former.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.980-985
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• 2002

Several tests are performed to evaluate road booming noise. Baseline test delivers the information of road noise characteristics. Coupling effect between structure and acoustics is obtained from the mode shapes and the natural frequencies by the modal test. Equivalent stiffness at joint areas between chassis and car-body system can be determined by the input point inertance test. Noise sensitivity of body mounting point of a chassis part can be obtained from the noise transfer function test with input point inertance test. Operational deflection shape makes us analyze the actual vibration modes of the chassis system under actual loading and find noise sources very easily. finally, the transfer function analysis is used to identify noise paths through the chassis system. However, all of the tests above mentioned must be performed to evaluate road booming noise. The objectives and the procedures of the tests are described in this paper. Also, the guideline for efficient road noise evaluation test can be found.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.43-48
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• 2011

• Journal of Power System Engineering
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• v.13 no.5
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• pp.40-45
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• 2009

This article deals with the transient analysis using multi-flexible body dynamics of a trailer vehicle, which is passing a bump on the flat road. In order to investigate the transient dynamic behavior of the trailer, we developed an equivalent finite element model for the trailer and a vehicle dynamic model for the truck using multi-body dynamics. The driving condition considered here is set as the trailer vehicle passes a bump on the flat road in 7km/h. And we investigate the time histories of vertical load and deflections on connecting points between the trailer and truck during the vehicle passes a bump. Due to the dynamic load resulted from the driving condition, additional stress concentrations are found in the trailer and the suspension connecting points between the trailer and rear axles along with kingpin.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.11
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• pp.1096-1103
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• 2010

This paper proposes CDC (Continuous Damping Control) algorithm and verifies in multi-body dynamic vehicle. In order to distinguish a road profile on driving, waviness calculated by the filtered vertical-accelerations of sprung and unsprung masses is introduced. Sky-hook control is used at a low waviness road and constant damping level control is used at a high waviness road, where the hard damping level is determined by waviness, roll rate, acceleration, and deceleration. The damping levels of ride, anti-roll, anti-squat, and anti-dive modules are calculated by tuning parameters which is dependent upon vehicle velocity. Therefore this high tunable algorithm is useful to improve the ride and handling performance under various driving conditions. In the simulations, tire and dampers are modelled by SWIFT (Short Wavelength Intermediate Frequency Tire) model and 1st order delay model, and results are compared with conventional damper's.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.8
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• pp.720-728
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• 2012

It is important for identification of noise and vibration problem of tire to consider influence of interaction between road and tire. A quantification of road noise is a challenging issue in vehicle NVH due to extremely complicated transfer paths of road noise as well as the difficulty in an experimental identification of input force from tire-road interaction. A noise caused by tire is divided into road noise(structure-borne noise) and pattern noise(air-borne noise). Pattern noise is caused by pattern shape of tire, which has larger than 500 Hz, but road noise is generated by the interactions between a tire and a vehicle body. In this paper, we define the quantitative analysis for road noise caused by interactions between tire and road parameters. For the identification of road noise, the chassis dynamometer that is equipped $10mm{\times}10mm $ square cleat in the semi-anechoic chamber is used, and the tire spindle forces are measured by load cell. The vibro-acoustic transfer function between ear position and wheel center was measured by the vibro-acoustic reciprocity method. In this study three tires with different type of mechanical are used for the experiment work.

• Journal of KSNVE
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• v.10 no.2
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• pp.247-253
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• 2000

The evaluation of the ride quality had been performed by the subjective method before ISO2631(International Organization for Stadard 2631) and BS6841(British Standard 6841) was precented, but many research programs have been performed by the objective method after that. On this study, the ride quality was evaluated related with the objective method which considered the vibration which the human body feels on the driver's seat while driving on the road. In particular, we made the shock absorber nonlinear model and also selected the suitable shock absorber in the part of the vibration which the human body feels into the simulation. The shock absorber of suspension was dealt with 3 cases respectively with the front wheel and rear wheel. The vibration of the car driving on the road can be transferred to the wheel, the suspension, the vehicle body, the seat and the human body. The signal which was gained from the seat(hip) and the floor(foot) of the human body was changed to the vibration signal which the human body felt through using the frequency weighting function. And then the performance of the shock absorber was calculated through the statistic processing.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.154-162
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• 2004

In this study, a mathematical model for analyzing the shifting transients of the passenger car with an automatic transmission is proposed. The proposed model comprises a power transmission system and a vehicle system, which are coupled. In order to extract the modeling parameters, on-road car test is carried out. The model is composed of a detailed powertrain, an engine/AT housing, a simplified suspension system, tires and a vehicle body model. On the test, the vehicle accelerations and pitch ratio are measured by using accelerometers and a gyro sensor. The speeds, the brake signal, and the throttle position are taken from sensors which already exist in the vehicle. Considering natural ftequencies, which is calculated from the measured accelerations, and the characteristic equation, vehicle model parameters are identified. Dynamic behaviors during upshift or downshift are simulated using the proposed vehicle model. By comparing and analyzing the simulation result and on-road car test data, the vibration of the Engine/AT housing influences the shifting transients. The effect of model parameters are also studied. Among model parameters, the location of engine mountings influences the vibration of the vehicle body.