• International Journal of Naval Architecture and Ocean Engineering
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• v.4 no.3
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• pp.183-198
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• 2012

Dynamic buckling, also known as parametric resonance, is one of the dynamic instability phenomena which may lead to catastrophic failure of structures. It occurs when compressive dynamic loading is applied to the structures. Therefore it is essential to establish a reliable procedure to test and evaluate the dynamic buckling behaviors of structures, especially when the structure is designed to be utilized in compressive dynamic loading environment, such as supercavitating underwater vehicle. In the line of thought, a dynamic buckling test system is designed in this work. Using the test system, dynamic buckling tests including beam, plate, and stiffened plate are carried out, and the dynamic buckling characteristics of considered structures are investigated experimentally as well as theoretically and numerically.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.421-426
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• 2009

Recently, the design process for a railway bogie frame in Europe has been carried out according to the norm EN 13749. The activities in the norm EN shall demonstrate that the design of the bogie frame fulfills the acceptances of 4 steps of the program such as structural calculation, static tests, fatigue test and on-tracks tests. At the end of the acceptance program, the on-tracks tests have the aim to measure the real stress history generated in operation and to verify that they are reasonably next to those calculated and measured on the test rig. Therefore, in order to assure the safety of the railway vehicle, it is important to examined the durability of that under load histories measured from on-tracks tests. In this study, under variable amplitude loading based on the actual acceleration history, fatigue analysis of the welding bogie frame is investigated by using durability software. Moreover, the fatigue life of the frame under the loading in the norm EN fatigue test condition is evaluated and compared with the life under variable amplitude loading.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.10 s.115
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• pp.1067-1073
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• 2006

In this paper, we present noise measurement results of 8 vehicles. The measurement was done by a close proximity method attaching surface microphones on the test vehicle. For the 9 road surface types constructed at Korean highway test road, the vehicles were tested from 50 to 120 km/h at the interval of 10 km/h in normal steady state and inertia cruising conditions. Using the results, we evaluate and discuss the effect of vehicle noise generation depending on the different conditions for vehicle type, speed, road surface and loading condition, especially focused on friction noise between tyre and road surface.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.428-433
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• 2006

In this paper, we present noise measurement results of 8 vehicles. The measurement was done by a close proximity method attaching surface microphones on the test vehicle. For the 9 road surface types constructed at Korean highway test road, the vehicles were tested from 50 to 120 km/h at the interval of 10 km/h in normal steady state and inertia cruising conditions. Using the results, we evaluate and discuss the effect of vehicle noise generation depending on the different conditions for vehicle type, speed, road surface and loading condition, especially focused on friction noise between tyre and road surface.

• Proceedings of the KSR Conference
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• 2002.10b
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• pp.1035-1040
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• 2002

Railway plate girder bridges have characteristics that are not show dominant frequency in dynamic response frequencies like obtained vertical acceleration on the bridge during the train passing because the train loading relatively bigger than the bridge self-weight. This paper experimentally confirmed in FFT result has various frequencies due to inherent characteristic of railway train loading. To establish classification of dynamic frequency range in railway bridge acceleration during the train passing, vibration frequencies result from experimental test are analyzed concerning actuation vibration factors. Factors are train velocity, train type, mass ratio of vehicle/bridge, stiffness of bridge, bridge/track and vehicle/track. From the result, it is proposed that the frequencty classfication table with corresponding factors. Using the proposed table to develop rehabilitation technique of the plate girder bridge, to expect vibration reduction and comfort enhancement of the railway plate girder bridge.

• Smart Structures and Systems
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• v.2 no.3
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• pp.275-293
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• 2006

For health monitoring purpose usually the structure is instrumented with a large scale and multichannel measurement system. In case of highway bridges, operating vehicle could be utilized to reduce the number of measuring devices. First this paper presents a static damage detection algorithm of using operating vehicle load. The technique has been validated by finite element simulation and simple laboratory test. Next the paper presents an approach of using this technique to field application. Here operating vehicle load data has been used by instrumenting the bridge at single location. This approach gives an upper hand to other sophisticated global damage detection methods since it has the potential of reducing the measuring points and devices. It also avoids the application of artificial loading and interruption of any traffic flow.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.11
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• pp.1126-1132
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• 2009

Bridge structures are designed to support ordinary loadings such as vehicles, wind, temperature and current as well as unexpected loadings like earthquakes and storm. Especially, the displacement of Flexible bridges like an suspension bridge under ordinary loading conditions is necessary to be monitored. In case of long span bridges, there are some difficulties in monitoring the displacement of center of the main span using traditional laser displacement sensors. In this study, the static and dynamic displacement responses due to vehicle loadings were measured by DGPS(differential global positioning system) technique. The displacement response data were compared with data obtained from traditional laser displacement sensors so that the static and dynamic behavior of the bridge under vehicle loadings was examined and the applicability of the displacement response measurement using DGPS technique was verified. The static and dynamic loading test for an self-anchored suspension bridge, So-rok Bridge, was performed using vehicles. The displacement response from DGPS technique and that from laser displacement sensors of the bridge monitoring system were compared. The amplitude of white noise from DGPS based measurement was about 7 mm and that of laser displacement sensor based measurement was about 3 mm. On the other hand, dynamic behavior of the center of main span from DGPS based measurement showed better agreement with influence line of the bridge than that from laser displacement sensors. In addition, there were some irregular and discontinuous variation of data due to the instability of GPS receivers or frequent appearance of GPS satellites. Post-processing via the reference station close to an observation post provided by NGII(National Geographic Information Institute) will be a counter-plan for these defects.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.5
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• pp.358-364
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• 2009

This paper is to investigate the influence of driving patterns of slow and high speed vehicles on the performance of continuously regenerating diesel particulate filter(DPF) system matched with operating conditions in field application. The DPF performance test for field application was carried out for two identical DPFs installed to slow and high speed vehicles. A slow speed vehicle was selected among local buses which have driving patterns to repeat running and stop frequently, while a high speed vehicle was prepared to have long route of high speed over 60km/h like inter-city buses. In this test, the regeneration performance on the DPF of slow speed vehicle deteriorated because of high soot load index(SLI) in spite of same balance point temperature(BPT) distribution for high speed vehicle. The DPF of slow speed vehicle melted in the end because the rapid increase of back pressure caused high temperature over $1200^{\circ}C$ in the ceramic wall of DPF. The PM components like ash collected to the filter in the DPF were analyzed in order to investigate the cause of the defect and provide an operation performance of DPF system. In the result of the analysis, high levels of lubrication oil ash(Ca, Mg, P, Zn) were detected.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.3
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• pp.127-141
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• 2014

A Vehicle Tracking System consists of GPS tracking device which fits into the vehicle and captures the GPS location information at regular intervals to a central GIS server, and GIS tracking server providing three major responsibilities: receiving data from the GPS tracking unit, securely storing it, and serving this information on demand of the user. GPS based tracking systems supporting a multi-session processing among RMA, RM, and RCP can make a quick response to various services including other vehicle information between RSU and OBU on demand of the user. In this paper we design RSU lower layers and RCP applications in OBU for a multisession processing simulation and test message processing transactions among RMA-RM and RM-RCP. Furthermore, we implement the additional functions of handling access commands simultaneously on multiple service resources which are appropriate for the experimental testing conditions. In order to make a multi-session processing test, it reads 30 resource data,0002/0001 ~ 0002/0030, in total and then occurs 30 session data transmissions simultaneously. We insert a sequence number field into a special header of dummy data as a corresponding response to check that the messages are received correctly. Thus, we find that GIS service system with a multi-session processing is able to provide additional 30 services in a same speed of screen presentation loading while identifying the number of session processing of Web GIS service, the number of OBU service, and the speed of screen presentation loading by comparing a single session and a multi-session of GIS service system.

• Journal of the Society of Disaster Information
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• v.13 no.1
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• pp.73-80
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• 2017

In this study, the panel joint behavior by the vehicle load moving on precast panel is analyzed. The frame was made for loading and the behavior was determined by using each measuring device. The static response of the panel was examined and compared with the theoretical value, and it was found that the characteristics were very reasonable. In addition, acceleration, velocity, and displacement were measured for dynamic impact evaluation, and the characteristics of moving load were analyzed in the test. The vibration frequency of the panel was measured for the dynamic response by the moving load, and the vibration characteristic was considered to be sensitive to the range of the load. As a result, it is considered that the dynamic response of the connection part should be careful in design because the characteristics are different according to the connection method.