Engineering safety diagnosis of collided subway electric multiple units (EMUs) was conducted for safety assessment. Several advanced engineering analysis techniques including nondestructive evaluation (NDE) techniques and stress and structural analyses programs, were performed for better understandings and exploration of failure analysis and safety concerns. NDE techniques such as ultrasonic testing and magnetic particle testing, were used to detect manufactureinduced and/or in-service defects and collision-induced flaws, and measure the dimensions of deformed and non-deformed parts on damaged EMUs due to a rear-end collision. Moreover, stress and structural analyses using commercial I-DEAS software provided important information on stress distribution and load transfer mechanisms as well as the amount of damages during the crash. A good agreement has been found between structural analysis results and the results of actual damages in EMUs during crash. In this investigation, various advanced engineering analysis techniques for the safety analysis of subway EMUs have been introduced and the analysis results have been used to rovide the critical information for the safety assessment of collided EMUs.
This study was carried out to classify forest vegetation structure of Jeoksansan in Deogyusan National Park from September 2007 to July 2008 using the DCCA ordination and phytosociological method. The vegetation of the Jeoksangsan was classified into Quercus mongolica community, Pinus densiflora community, Q. variabilis community, Q. serrata community, Carpinus laxiflora community and Fraxinus mandshurica community. Ecological characteristics such as species composition, layer structure, vegetation ratio, and the distribution of individual trees by DBH were significantly different among communities.The order of important value of the forest community with DBH 2cm above plants was Q. mon-
Engineering safety diagnosis of crashed subway electric multiple units (EMUs) was
conducted for safety assessment. Several advanced engineering analysis techniques including
nondestructive evaluation (NDE) techniques and stress and structural analyses programs, were
performed for better understandings and exploration of failure analysis and safety concerns. NDE
techniques such as ultrasonic testing and magnetic particle testing, were used to detect
manufacture-induced and/or in-service defects and collision-induced flaws, and measure the
dimensions of deformed and non-deformed parts on damaged EMUs due to a rear-end collision.
Moreover, stress and structural analyses using commercial I-DEAS software provided important
information on stress distribution and load transfer mechanisms as well as the amount of damages
during the crash. A good agreement has been found between structural analysis results and the results
of actual damages in EMUs during crash. In this investigation, various advanced engineering analysis
techniques for the safety analysis of subway EMUs have been introduced and the analysis results have
been used to provide the critical information for the safety assessment of crashed EMUs.
In these days, most urban railway vehicles have been serviced under the random load
application. However, it is considered to be a major factor of safety to predict the fatigue life for
structures. It is thus required that fatigue assessment method for cumulative damage approach while
Korea domestic regulations practices only the only has endurance limit approach. With this endurance
limit approach, fatigue life prediction is impossible. In this research, the fatigue assessment for urban
transit structure by using of cumulative damage approach method and related theories are presented.
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