• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3833-3838
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• 2009

This paper introduces a measurement system for mechanical properties of sport shoes using an industrial robot. The robot system used in this paper is a commercial Puma type robot system(FARA AT2 made by SAMSUNG Electronics) with 6 joints and the end-effector is modified to produce a human walking motion. After analyzing human walking with a high speed video camera, each joint angle of the robot system is extracted to be used in the robot system. By using this system, ground impact forces were measured during stepping motion with 3 different shoe specimens made of 3 different hardness outsoles, respectively. As other mechanical properties, both bending moments to bend the toe part of the same specimen shoes and pronation quantities during walking motion were measured as well. In the impact test with the same depth of deformation under the ground level, the effect of the outsole hardness was clearly appeared such that the harder outsole produces the higher ground reaction force. The bending test and the pronation test also show proportional increments in the bending stiffness and the moment Mx according to the outsole hardness. Throughout such experiments, the robot system has produced consistent results so that the system could be used in obtaining valuable informations for a shoe designing process.

• Journal of Biosystems Engineering
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• v.13 no.4
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• pp.20-29
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• 1988

Properties of agricultural products are important for engineering design and analysis with respect to their mechanical harvesting, handling, transporting and processing. Researcher have presented the data of properties for various kinds of agricultural products. These data, however, are obtained from the materials produced in foreign countries, and a very few data could be found in Korea. In this paper, emphasis put on the importance of measuring the properties of agricultural products through an extensive review of literatures, and some experimental results on the viscoelastic and elastic properties of the materials are presented. Viscoelastic characteristics of some agricultural materials, specifically the force-deformation-time relationship of the whole orange and cylindrical samples of cheese under different types of loading were investigated. In elastic test, the response of apple during an impact and the relationships among various parameters such u degree of damage, drop height and absorbed energy were determined.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.53-56
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• 2005

Aircraft noise is a important problem to inhabitants near airports. INM is one of programs for determining the predicted noise impact in the vicinity of airports. It has been widely using for engineers to evaluate aircraft noise. However it is difficult to predict aircraft noise in case of lack of exact INM input data. The exact informations about a fighter plane are not known well for a security problem. This study presents methods of reducing errors between measurement and simulation when the exact INM input data is not known. Especially we adjusted the thrust force of aircraft engine and reduced the error.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.185-190
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• 2001

The structure borne noise of the air-conditioner, which degrades the noise quality, is hardly reduced by the general noise treatments. It can be effectively reduced by eliminating the structural vibration which the noise originates from. The rubber vibration isolator prevents the dynamic force induced by the fan driving motor from exciting the chassis structure, which finally reduces the structure borne noise. The dynamic properties of the vibration isolation system such as the natural frequency of the vibration isolation and loss factor of the rubber isolator, need to be experimentally evaluated. In this paper, these dynamic properties were obtained by the resonant method using the impact hammer for 3 types of the isolator specimens. It is known that the isolation natural frequency of the axial direction of the rubber isolator is two times higher than that of the radial direction, and is proportional to the hardness of the rubber specimen.

• Journal of the Korea Safety Management & Science
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• v.12 no.4
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• pp.53-60
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• 2010

When a fire breaks out, it is difficult to find out the causes of the fire, because combustible things around fire scene are usually burnt away. Among many causes of fires are electronic wires, this thesis deal with the destroyed sheath of electronic wires caused by fire. It was studied with the use of measurement devices focusing on the distinctions of wires and conductors. This study especially emphasized the process of deterioration, burning pattern, and composition of electronic wire conductor. It also has a phenomenological approach to the distinctive cause of fire by some partial force. The fire prevention methods have been suggested through the analysing results of fire patterns. This study is expected to be a useful material for analyzing various electrical fires.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.4
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• pp.424-430
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• 2008

A new active vibration measurement system in electric power transmission line is presented, using in the nondestructive test. With a permanent magnet and a couple of coils, the system exerts impact force to a test object and in turn picks up the vibration of the object. The natural frequency with the amplitude obtained from the system are used as a basis for the detection of defects in the object. The system is controlled by an electronic device designed to facilitate the fully automated testing process with consistent repeatability and reliability which are essential to the nondestructive test. The system is expected to be applied to the wide area of defect detection including the classification of mechanical parts in production and inspection processes.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.3 s.120
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• pp.249-256
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• 2007

Aircraft noise is a serious problem to inhabitants near airports. INM is one of programs for determining the predicted noise impact in the vicinity of airports. It has been widely used for engineers to evaluate aircraft noise. However it is difficult to predict aircraft noise in case of lack of exact INM input data. The exact informations about a fighter plane are not known well for a security problem. This study presents methods of reducing errors between measurement and simulation when the exact INM input data is not known. Especially we adjusted the thrust force of aircraft engine and reduced the error.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.2
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• pp.43-54
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• 1989

In this paper, measured and calculated responses are compared in order to give how the static and dynamic responses occurred in steel railway bridges due to train loads could be calculated appropriately. From this, it is investigated how the impact factors are varied by changing the train speed above 100km/h Field measurement is carried out by the steel strain gages and displacement transducers at the main design points, and then the static and dynamic response, fundamental frequencies, damping ratios and impact factors of the bridges are obtained. Static analysis is done using the computer program developed according to three dimensional matrix structural analysis in which the trains and bridges are modelled as 1,2 and 3 dimensions. Dynamic analysis is done according to 2 approaches, the moving force and mass problem. In moving force problem, the solutions are obtained by the modesuperposition-method and in moving mass problem by the direct integration method. From this study, it is known that in order to obtain the static response in the railway bridges, the bridge could be modelled by 1 or 2 dimension as in the highway bridge, however the response ratio(measured/calculaled) is high comparing to the highway bridges. By the way, the dynamic response should be obtained by the moving mass problem. And by comparing the measured and code specified impact factors, it is known that the factors specified in the present railway bridge code are very safe under the present service speed below 100km/h. However, because the factors become very high under the speed above 100km/h, especially in the simple plate girder bridge, it is thought that the code specification on impact factor should be discussed enough under the rapid transit system.

• Korean Journal of Applied Biomechanics
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• v.26 no.4
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• pp.413-420
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• 2016

Objective: The purpose of this study was to analyze and compare different kinds of outdoor walking shoes in terms of muscle fatigue and ground reaction force on walking, and to provide foundational data for developing and choosing outdoor walking shoes that fit the users. Method: The study subjects were 30 healthy men. The experiment was conducted by using outdoor walking shoes with different inner and outer harnesses of the midsole, and shapes of the outsole. For data collection, electromyography was used to measure the muscle fatigue of the anterior tibial muscle and gastrocnemii, which contribute to the dorsiflexion and plantarflexion of the ankle joint, and the biceps muscle of the thigh and lateral great muscles, which contribute to the flexion and extension of the knee joint. A GRF measurement device was used to measure the X, Y, and Z axes. Results: In the type A outdoor walking shoes, regarding the hardness of the midsole, the inner part was soft, while the outer part was hard. The vertical ground reaction force was the lowest, which means least impact while walking and light load to the knees and ankles. The type C outdoor walking shoes were intended to provide a good feel in wearing the shoes. The tibialis anterior, biceps femoris, and gastrocnemii indicate low fatigue, which means that during a long-distance walk, it will minimize the fatigue in the muscles of the lower limbs. Conclusion: To sum up the study results, the different types of outdoor walking shoes indicate their unique characteristics in the biomechanical comparison and analysis. However, the difference was not statistically significant. Thus, a systematic and constant follow-up research should be conducted to cope with expanding market for outdoor walking shoes. Lastly, this study is expected to present foundational data and directions for developing outdoor walking shoes.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.443-448
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• 2020

In this study, field measurements were performed to analyze the effects of train types (AREX, AREX Express, KTX, KTX-Sancheon) and train speeds on the dynamic behavior of the direct fixation track structure on Yeongjong grand bridge by bridge type (truss bridge, suspension bridge). Based on field measurement results, the track impact factor and train running stability (coefficient of derailment, Rate of wheel load reduction, lateral displacement of rail head) are compared with domestic and foreign standards and regulations to influence the dynamic behavior of direct fixation track. As a result, the differences in the dynamic behavior of the direct fixation tracks by the type of bridges of Yeongjong bridge are not significant, but it was analyzed that these were more directly affected by the magnitude of the train load. Therefore, it is necessary to establish the reinforcement plan of the direct fixation track structure on Yeongjong grand bridge in consideration of the increase of the track impact factor and dynamic track force.