• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.195-196
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• 2002

Studied is fretting wear behaviour of transversely vibrating tube which is supported by springs and dimples. This simulates the fuel rod fretting due to flow-induced vibration in a nuclear reactor. The contact between spacer grid springs and fuel cladding tubes arc brought into focus in this paper. From the mechanical viewpoint, a concave contact shape of spring is considered to perform a wider distribution of the contact stress. Sliding/impacting experiments are conducted in air at room temperature with the conditions of positive contact force and gap existence to accommodate the mechanical condition between the fuel rod and the grid spring during reactor operation. It is found that wear region is separated and wear volume becomes larger as the supporting condition becomes poorer. Spring and dimple cause similar wear.

• KSTLE International Journal
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• v.3 no.1
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• pp.60-67
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• 2002

Wear on the tube-to-spring contact is investigated experimentally, The vibration of the tube causes the wear while the springs support it As for the supporting conditions, the contacting normal farce of 5 N,0 N and the gap of 0.1 mm are applied. The gap condition is for considering the influence of simultaneous impacting and sliding on wear. The wear volume and depth decreases in the order of the 5 N,0 N and the gap conditions. This is explained from the contact geometry of the spring, which is convex of smooth contour, The contact shear force is regarded smaller in the case of the gap existence compared with the other conditions. The wear mechanism is considered from SEM observation of the worn surface. The variation of the normal contact traction is analysed using the finite element analysis to estimate the slip displacement range on the contact with consulting the fretting map.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.05a
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• pp.63-70
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• 2002

Wear on the tube-to-spring contact is investigated experimentally. The wear is caused by the vibration of the tube while the springs support it. As for the supporting conditions, applied are the contacting normal force (P) of 5 N, just-contact (P = 0 N) and the gap of 0.1 mm. The gap condition is tried far considering the influence of simultaneous impacting and sliding on wear. Results show that the wear volume increases in the order of the gap, the just-contact and the 5 N conditions. This is explained from the contact geometry of the spring, which is convex of smooth contour. The contact shear force is regarded smaller in the case of the gap existence compared with the other conditions. Wear mechanism is considered from SEM observation of the worn surface. The variation of the normal contact traction is analysed using the finite element analysis to estimate the slip displacement range on the contact with consulting the fretting map previously obtained.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.448-454
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• 2000

Piled multi-block system has been frequently adopted in the historic structures or monuments of cultural heritage. It is well known that such a structural system is very vulnerable to the earthquake shaking. If the structure is of slender type, then it may experience overturning at very low level intensity of ground shaking. One of the methods used to protect such structures from earthquake is seismic isolation system. But the behavior of multi-block systems mounted on the isolated basis is not well understood yet. In this paper we investigate the dynamic behavior of single slender rigid block mounted on the three different isolation systems, i.e., P-F system, FPS and LRB system. Sliding at the isolation interface of P-F system and FPS is formulated based on Coulomb friction. The mounted single block is assumed undergoing rocking or sticking only. Impacting of a single block is described using distinct element method (DEM). Free vibrations due to a prescribed initial conditions are studied. Responses to the harmonic excitation and earthquake motions are calculated

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.4
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• pp.108-112
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• 2007

This study analyzes the dynamic fracture phenomenon that aluminum rod impacts aluminum plate or rigid plate and deforms. The value of von-Mises stress in the instance that aluminum rod deforms on rigid plate after contact becomes 1.3 times as large as that in the instance of contact. On the contrary, the value of von-Mises stress in the instance that aluminum rod goes through aluminum plate after contact becomes 0.7 times as small as that in the instance of contact. The value of internal energy in the instance that aluminum rod contacts aluminum plate becomes 2.3 times as large as that in the instance that aluminum rod contacts rigid plate. But the value of kinetic energy in the instance that aluminum rod contacts aluminum plate becomes 0.9 times as small as that in the instance that aluminum rod contacts rigid plate. The value of internal energy in the instance that aluminum rod goes through aluminum plate after contact becomes 0.7 times as small as that in the instance that aluminum rod impacts rigid plate and deforms. And the value of sliding energy in the instance that aluminum rod contacts aluminum plate becomes 0.2 times as small as that in the instance that aluminum rod contacts rigid plate. The value of total energy in case that aluminum rod impacts aluminum plate becomes 0.9 times as small as that in the case that aluminum rod impacts rigid plate.