This paper presents a computational fluid dynamics (CFD) analysis to investiagate the effect of expansion chamber on overpressure reduction in protective tunnels subjected to detonation of high explosives. A commercial CFD code, Viper::Blast, was used to model the blast waves in a protective tunnel with a length of 160 m, width of 8.9 m and height of 7.2 m. Blast scenarios and simulation matrix were establihsed in consideration of the design parameters of expansion chamber, including the chamber lengths of 6.1 m to 12.1 m, widths of 10.7 m to 97 m, length to width ratios of 0.0 to 5.0, heights of 8.0 m and 14.9 m, and ratios of chamber to tunnel width of 1.2 to 10.9 m. A charge weight of TNT of 1000 kg was used. The mesh sizes of the numerical model of the protective tunnel were determined based on a mesh convergence study. A parametric study based on the simulation matrix was performed using the proposed CFD tunnel model and the optimized shape of expansion chamber of the considered tunnel was then proposed based on the numerical results. Design recommendations for the use of expansion chamber in protective tunnel under blast loads to reduce the internal overpressures were finally provided.

본 논문은 동역학의 새로운 변분이론인 확장 해밀턴 이론을 열 탄성과 공극 탄성에 적용하여 더욱 일반화하는 것에 그 주 요 목적이 있다. 이를 위해 열 탄성학에 대한 이론 적용이 우선적으로 검토되었고, 열 탄성-공극 탄성의 유사성을 바탕으로 공극 탄성에까지 그 이론이 확장되었으며, 각 경우에 대한 푸리에 변환을 통해 그 적정성을 확인하였다.

Abstract In this study, the antioxidant activity of water and ethanol extracts from Hibiscus esculentus, Cirsium japonicum, Zizania latifolia and Kalopanax pictus for functional food source were examined. The optimal conditions for phenolic compounds extraction from medicinal plants were at 50% ethanol with Hibiscus esculentus and Cirsium japonicum var. ussuriense, at 40% ethanol with Kalopanax pictus and at 60% ethanol with Zizania latifolia. The total phenolic contents from the extracts of medical plants were determined to be 2.72~34.15 mg/g in the water extracts and 2.83~34.23 mg/g in the ethanol extracts. The electron-donating abilities (EDA) of the water and ethanol extracts were both above 74% at the low concentration of 50 μg/mL. The ABTS radical-cation decolorization was above 88% at 100 μg/mL concentration in all the extracts of various medicinal plants. The antioxidant protection factor (PF) in the water and ethanol extracts of the Cirsium japonicum var. ussuriense extracts was 1.73 ± 0.02 PF and 1.76 ± 0.01 PF at 50 μg/mL concentration respectively, and was higher than those of the other medicinal-plant extracts. The TBARs inhibition rates of all the medicinal-plant extracts, were above 80% at the 50 μg/mL concentration except Hibiscus esculentus. These results confirmed that the various oriental medicinal plants (Hibiscus esculentus, Cirsium japonicum var. ussuriense, Kalopanax pictus and Zizania latifolia) that were included in this study are useful anti-oxidant and functional-food resources.

In this study, sensitivity analyses on the blast response of the steel-plate concrete(SC) walls subjected to explosive blast loads were carried out. In order to evaluate various cases effectively we set up the blast response evaluation procedure of SC walls, and developed the blast response evaluation program of SC walls using equivalent SDOF method. Finally, the effects of the various design parameters on the blast response of SC walls were investigated using the developed program.

In this study, a study on the structural safety evaluation method of steel-plate concrete(SC) walls subjected to explosive blast loads were carried out. Various approaches to assess the blast response were reviewed, such as static method, equivalent SDOF method, explicit FE method, and computational fluid-dynamic method. Finally, preliminary blast response evaluation of SC walls were performed using equivalent SDOF method.