• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1227-1234
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• 2012

In this study, fatigue tests were carried out using real-scale pipe bend specimens with wall-thinning defects under a cyclic bending load together with a constant internal pressure of 10 MPa. The wall-thinning defect was located at the extrados and the intrados of the pipe bend specimens. A fully reversed cyclic in-plane bending displacement was applied to the specimens. For the pipe bends with wall thinning at the extrados, an axial crack occurred at the crown of the pipe bend rather than at the extrados where the defect was located. In addition, the fatigue life was longer than that of a sound pipe bend predicted from the design fatigue curve in ASME Sec.III, and it was less dependent on the axial length of the wall-thinning defect. For the pipe bends with wall thinning at the intrados, a circumferential crack occurred at the intrados. In this case, the fatigue life was much shorter than that of a sound pipe bend predicted from the design fatigue curve, and it clearly decreased with decreasing axial length of the wall-thinning defect.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.7
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• pp.1006-1013
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• 2004

Operating experience of steam generators shows that the tubes are degraded by stress corrosion cracking, fretting wear and so on. These defected tubes could stay in service if it is proved that the tubes have sufficient structural margin to preclude the risk of tube bursting. This paper provides detailed plastic limit pressure solutions for through-wall cracks in the steam generator tubes. These are developed based on three dimensional(3D) finite element analyses assuming elastic-perfectly plastic material behavior. Both axial and circumferential through-wall cracks in free span and in u-bend regions are considered. The resulting limit pressure solutions are given in a polynomial form, and thus can be simply used in practical integrity assessment of the steam generator tubes.

• The Journal of the Korea Contents Association
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• v.5 no.1
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• pp.229-236
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• 2005

Testing time and power consumption during testing System-On-a-Chip (SOC) are becoming increasingly important as the IP core increases in a SOC. We present a new algorithm to reduce the scan-in power and test data volume using the modified scan latch reordering. We apply scan latch reordering technique for minimizing the hamming distance in scan vectors. Also, during scan latch reordering, the don't care inputs in scan vectors are assigned for low power and high compression. Experimental results for ISCAS 89 benchmark circuits show that reduced test data and low power scan testing can be achieved in all cases.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.9
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• pp.1059-1064
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• 2012

In this study, tensile tests were performed on specimens that simulated the cold-bending and heat-treatment of pipe bends to understand the mechanical properties of pipe bends manufactured by cold-bending followed by heat-treatment for relieving residual stress. The strength and ductility of cold-worked materials were respectively found to be higher and lower than those of the parent material although heat-treatment was carried out to relieve residual stress. In addition, the increase in strength and decrease in ductility were proportional to the applied strain levels for cold-working. It was thus inferred that the intrados and extrados regions of pipe bends that were cold-bended and heat-treated show higher strength and lower ductility compared to the parent straight pipe and that the mechanical properties at the crown region are nearly the same as those of the parent straight pipe.

• Korean Journal of Heritage: History & Science
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• v.56 no.1
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• pp.64-78
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• 2023

This article examines the background and meaning of the construction of Josadang Hall in Buseoksa Temple, Yeongju, by Seolsan Cheonhee(1307~1382) in the late 14th century through the characteristics of the hall's mural. Six guardian deities(the Four Heavenly Kings in the center, Indra and Brahma on each side of the kings) are depicted on the southern wall(location of the entrance) of the Josadang, facing the statue of the great monk Uisang(625~702 AD) on the north wall. This mural is the oldest among Korean temple murals and exhibits very unique characteristics. In general, scenes from the scriptures are depicted on the back wall of the central statue. In contrast, the Josadang mural depicts only the guardian deities facing the main statue with no scene description. The appearance of the deities, who seem to protect the main statue of the monk Uisang, and their expressions, as if drawn from relief statues, are not seen in other murals. Nevertheless, it is similar to the stupas of the Seon(Ch. Chan 禪) sect monks established from the late Silla(57 BC~935 AD) through early Goryeo(918~1392 AD), with guardian deities on their surface. The iconography of the deities is a classic form of the late Silla to early Goryeo. The fact that the Josadang was built to commemorate Uisang, who founded the Korean Hwaeom sect(Ch. Huayan sect, 華嚴宗), and that guardians were placed to protect Uisang's statue reveals the concept of worship for the monk who founded the sect. As a result, the reason Cheonhee built the hall can also be understood as an extension of the ideology behind the construction of the stupas of the Seon sect monks. The problem, however, is that Cheonhee is a monk of the Hwaeom sect, and Buseoksa is a representative temple of the Hwaeom sect, not the Seon sect. Therefore, to better understand the background of the hall's construction, this article examined the situation of Goryeo Buddhism in the 14th century as well as the activities of Seolsan Cheonhee. Since Ganhwa Seon(Ch. Kanhua Chan, 看話禪) was dominant in the 14th century, Cheonhee went to study in the Yuan Dynasty(1271~1368 AD) at the age of 58 and was approved by Chinese Ganhwaseon monks before taking the position of Guksa(國師 national monk). However, he was eventually pushed to Buseoksa Temple, where he worked hard to rebuild it. Cheonhee most likely sought to expand the Hwaeom sect, which had been shrinking compared to the Seon sect, by enhancing power with the reconstruction of Buseoksa. The desire that the Hwaeom sect, which was losing its power due to the rise of the Seon sect in the 14th century, attempted to develop it by building Josadang hall, is well revealed by the Josadang murals.