• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.6
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• pp.154-161
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• 1995

There are several kinds of driving conditions according to the characteristic of each vehicle diver. Automaker produces vehicle strong enough to satisfy this several driving conditions at the point of vehicle durability. In order to develop the car in a short period, Automaker engineer tests vehicle at serveral accelerated durability test roads. Before testing the vehicle durability, test engineer must know how much this test road severe than general field road which is composed of high way, city road, paved road and unpaved road. This paper suggests two types of road severity test method that is using relative fatigue life prediction method and using absolute fatigue life prediction method, and also present the merits and demerits of two test methods.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.357-361
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• 2003

According to the remarkable reduction of the vehicle noise, the important of tire noise which is generated from the vehicle and the necessities of the researches for the noise reduction are emphasized. In this study, we have studied the road noise which is excited by the interaction between tire and road. In order to evaluate the road noise, we carry out the subjective test(feeling test). In order to consider the effect of the vehicle suspension for the tire/road noise, we are equipped with identical tires on the differential vehicle suspension and evaluate the road noise. In order to consider the effect of the tire structure for the tire/road noise, we evaluate the some tires with various structures. From the test results, we fine that the difference of road noise is generated by the variation of the vehicle suspension. Also, we can select the optimized tire structure which can be reduced the road noise.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.1
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• pp.128-141
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• 1994

This roport explain the basic theory of desinging the accelerating durability test road and the role of each factors contributing to test road surface profile. Also this road is designed by considering the charactors of vehicle suspension system and condition of driving. In test road, the factors affecting to the vehicle Structural durability are correlation among surface shape of road profile, frequency of vehicle suspension system, distribution of axletwist angle and vibration profile height Road PSD magnitude and frequency delay is used to control these factors relation.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.91-96
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• 2008

As a remarkable reduction of the vehicle noise, the important of tire noise which is generated from the vehicle and the necessity of the research for the noise reduction is being emphasized. In this study, the road noise which is excited by the interaction between tire and road has been studied. The subjective test(feeling test) according to SAE J1060 rating scale is applied to the evaluation of the road noise. The combination of the several tires and vehicles are made to consider the effect of the vehicle suspension and the tire structure for road noise. The vehicles with 3-different suspension system are applied to road noise test and the eight kinds of tires are selected. As the results, the effects of the vehicle suspension and tire structure which affects on road noise are investigated.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.128-135
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• 2005

This paper presents a scheme for experimentally analyzing bounce, roll and pitch frequencies of major systems of a large truck using a multi-axial road simulator. The excitation input (amplitude and frequency range) fur a frequency response test with the multi-axial road simulator is selected in order that bounce, roll and pitch modes are not coupled each other, the excitation amplitude can be reproduced in a specified excitation frequency range, and tires do not lose contact with posters. Three accelerometers, one gyroscope and four displacement meters are used in the frequency response test using the multi-axial road simulator. The reliability of the presented bounce mode frequency response test scheme is validated by comparing the result from a test using the multi-axial road simulator with the result from a road driving test. The road driving test is performed with velocities of 20km/h and 30km/h, and in an unladen state. The vertical accelerations at the cab and the front axle are measured in the road driving test. The roll and pitch mode frequency response tests are also performed with the presented frequency response test scheme. Roll and pitch frequencies of major systems of a large truck that are hard to acquire from a road driving test are analyzed as well as bounce frequency.

• International Journal of Highway Engineering
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• v.18 no.4
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• pp.69-75
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• 2016

PURPOSES : In this study, we evaluated changes in the retroreflectivity and luminance of phosphorescent road line markings with changes in glass beads and line marking thickness. METHODS : The color of line markings affects their retroreflectivity. Using a chromaticity test, we conducted the analysis of whether phosphorescent road line markings adhered to the "KS M 6080" standard. Then, we measured the dry retroreflectivity and wet retroreflectivity for various glass bead refractive indices. We conducted wet retroreflectivity test using the EN 1436 standard as the basis. We also conducted luminance tests for different glass bead refractive indices and line marking thicknesses. RESULTS : 1. Phosphorescent road line markings specimens satisfied the "KS M 6080" standard. 2. In dry retroreflectivity test, phosphorescent road line markings sprayed with glass beads satisfied the national police agency standard ($240mcd/(m^2{\cdot}Lux)$). Wet retroreflectivity test results showed that except for one type of No.1 glass beads, phosphorescent road line markings specimens sprayed with glass beads of one type of No.3 and two types of No.1 satisfied the national police agency standard ($100mcd/(m^2{\cdot}Lux)$). 3. Phosphorescent road line markings had higher retroreflectivity than non-phosphorescent road line markings in the dry condition. 4. Phosphorescent road line markings sprayed with glass beads demonstrated improved luminance. Luminance increased with higher glass bead refractive index and with increased line marking thickness. However, when the thickness crossed a certain threshold, phosphorescence ceased to increase; this is a characteristic of the phosphorescence phenomenon. CONCLUSIONS : Visibility across short distances can be ensured when phosphorescent road line markings are sprayed with glass beads, because of the retroreflection phenomenon. It is also possible to ensure far visibility using phosphorescent road line markings.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.962-965
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• 2002

Full scale durability test in the laboratory is an essential of any fatigue life evaluation of components or structures of the automotive vehicle. Component testing is particularly important in today's highly competitive industries where the design to reduce weight and production costs must be balanced with the necessity to avoid expensive service failure. Generally, Hydraulic road simulator is used to carry out the fatigue test and the vibration test. In this paper, the algorithm and software to realize the real road profile are developed. The operation software for simultaneously controlled multi-axial simulator is developed and the input and output data are displayed window based PC controller in real time. The software to generate the real road profile are developed. This paper developed a road profile reappearance software and simultaneously apply 3-axial actuator to white noise, so we verified the propriety of reappearance software through accomplishes an real test.

• International Journal of Automotive Technology
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• v.4 no.1
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• pp.21-30
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• 2003

In this paper a systematic test procedure for evaluation of road-induced noise of a vehicle and guidelines for each test are presented. Also, a practical application of the test procedure to a small SUV is presented. According to the test procedure, all the tests were performed to evaluate road-induced booming noise that is in low frequency range. First of all the information on characteristics of road-induced noise was obtained through baseline test. Coupling effects between body structure and acoustic cavity of a compartment were obtained by means of modal tests for a structure and an acoustic cavity. Local stiffness of joint areas between chassis system and car-body was determined by test for measurement of input point inertance. Noise sensitivities of body joints to operational forces were obtained through test for measurement of noise transfer functions. Operational deflection shapes made us analyze behaviors of chassis system under running condition and then find sources of noise due to resonance of the chassis system. Finally, Principal Component Analysis and Transfer Path Analysis were utilized to investigate main paths of road-induced noise. In order to evaluate road-induced booming noise exactly, all of tests mentioned above should be performed systematically.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.326-331
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• 2006

The durability of recent motors is longer than the past one because there are the rapid technique development of the automobile industry and the vehicle maintenance of users. And then the importance of the durability test due to vibration is increased from day to day. So full vehicle and parts companies accomplish the durability test using various methods. The most public test method among them is the reliable field test but it bring on higher cost and period of the development process. The durability test using MAST(multi axis simulation table) is a solution in order to improve the development process of automobiles. Generally its excitation source uses the optimized road profiles that are obtained by the road test of belgian road, country road, cobbleston road and so on instead of a real field but the interrelations and influences accordingly vehicle damage are considered by a field test between specific roads and real fields in the first place. Therefore this study, in order to accomplish a basic research for the durability test using the MAST, performed on the real field driving test at various domestic roads and the results which are analyzed by PSD(power spectrum density) are compared with relative sensitivity among the roads. Consequently they can present a basic material for generation of road profiles which is applied to the durability test using MAST.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.5
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• pp.105-111
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• 2003

The three-axis road simulator is the test equipment which can simulate the standardized road conditions for the durability evaluation of automotive components such as suspensions. The road load data are collected and acquired from a vehicle test, and then these data are used to simulate road load conditions by the road simulator which consists of hydraulic actuators, link mechanism and servo controller. The link mechanism must be designed in consideration of the dynamic effect and interference during three axes motions in order to generate accurate motions. In this paper, the structural and kinematic analysis of the link mechanism is performed, and these results can be used for developing the three-axis road simulator. The three-axis road simulator provides considerable savings in cost, development time, and testing risk during developing automotive components.