• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
• /
• pp.293-298
• /
• 2003

The rockfall protection fences are installed to reduce rockfall damage in roads side slopes. The energy absorbing capacity of widely used rockfall protection fences is about 50kJ, But in many cases, rockfall protection fences are easily damaged even by a low level of rockfall energy. The objective of this paper is to verify the energy absorbing capacity of rockfall protection fences and investigate the behavior of them by rockfall. The LS-DYNA3D, a finite elements analysis program for dynamic movement of three dimensional objects, is used to perform the numerical simulations. In the result it is shown that rockfall protection fences absorb half of standard absorbing energy or less than it. It is inadquate for the rockfall protection fences to perform the principal function. To improve the performance of the fences, new rockfall proctection fence is proposed and numerical simulation is performed.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2003년도 추계 학술발표회논문집
• /
• pp.461-466
• /
• 2003

The rockfall protection fences are installed to reduce rockfall damage in roads side slopes. The energy absorbing capacity of widely used rockfall protection fences is about 50kJ. But in many cases, rockfall protection fences are easily damaged even by a low level of rockfall energy. The objective of this paper is to verify the energy absorbing capacity of rockfall protection fences and investigate the behavior of them by rockfall. The LS-DYNA3D, a finite elements analysis program for dynamic movement of three dimensional objects, is used to perform the numerical simulations In the result, it is shown that rockfall protection fences absorb half of standard absorbing energy or less than it. It is inadquate for the rockfall protection fences to perform the principal function. To improve the performance of the fences, new rockfall proctection fence is proposed and numerical simulation is performed.

• Structural Engineering and Mechanics
• /
• 제12권5호
• /
• pp.541-558
• /
• 2001

The design specifications of guard fences in Japan were reexamined and the revised specifications were implemented from April 1999. Because of the huge consumption in time and cost to test the performances of full-scale guard fences in the field, some assumptions are adopted while modifying the design specifications, and numerical analyses are necessary to confirm the impact performance and safety level of new types of steel highway guard fences. In this study, the finite element models are developed for the heavy trucks and steel highway guard fences to reenact their behaviors, and the solution approach is carried out using nonlinear dynamic analysis software of structures in three dimensions (LS-DYNA). The numerical simulation results are compared with the full-scale on-site testing results to verify the proposed analysis procedure. The collision process is simulated and it is also made possible to visualize the movement of the truck and the performances of guard fences. In addition, the energy shift of the truck kinetic energy to the truck and guard fence Internal energy, and the energy absorption of each guard fence component are studied for the development of a new design methodology of steel highway guard fences based on the energy absorption capacity.

• 건축역사연구
• /
• 제28권5호
• /
• pp.7-18
• /
• 2019

The "Imwon Gyeongjeji(林園經濟志)", the largest encyclopedia of the Late Joseon Dynasty covers the details of the materials and construction methods related to everyday life's facilities. It is very useful to examine the "Imwon Gyeongjeji" for studying the materials and construction methods of the fences in traditional dwellings. Therefore, we tried to find the characteristics of the traditional fences exhibited in the "Imwon Gyeongjeji" by examining the construction methods shown in the book by structure of the fence. The results are as follow. First, the nine types of fence were listed in the "Imwon Gyeongjeji". Second, we could figure out the construction methods according to the structure of fences. The fence is divided into three parts: foundation, body, and roof. The body of the fence is a characteristic part distinguishing the types of fence. The foundation and the roof are related to the durability of the fence, regardless of the type of fence. The "Imwon Gyeongjeji" showed a robust manner in building fences than known today. Third, we found that the introductions and transformations of certain fence types. Fences such as Chuibyong(翠屛), Jeon Doldam(甎墻) and Bunjang were originated from China, yet has developed unique Korean styles in Joseon. It could also be seen that Kajo Zhang(哥窯墻) and Yonglong Zhang(玲瓏墻) were special fence types imported from China. It is not certain that the fences depicted in the "Imwon Gyeongjeji", represent the whole features of Joseon fences, but it is certainly an important literature to understand the structure and design of traditional fences of the Late Joseon Dynasty.

• 한국환경과학회지
• /
• 제7권1호
• /
• pp.20-26
• /
• 1998

In establishing artificial fences in a certain locality, type of its area or wind blown against them from the front side is primarily considered. Researchers on fences also concentrate on upstream, wand blown against them from the front side In 90$^{\circ}$ angle. In this research, simulations were carried out on the direction of wind changed by each season, and regardless of seasonal wind, on the fences effect of wind direction on fences, throu호 an atmospheric boondary layer wind tunnel. When I compared the velocity distribution of upstream against the fences in 90$^{\circ}$ angle with that of 75$^{\circ}$, 60$^{\circ}$, and 45$^{\circ}$ respectively, the velocity distribution at downstream of the latter cases generally surpassed that of the former one.

• 농촌계획
• /
• 제13권1호
• /
• pp.33-40
• /
• 2007

The purpose of this paper is to analyze the value of stone fences in Jeju Island. The result that executes attitude survey to local resident and visitor can be summarizing as following. First are the function and the value of Jeju traditional stone fences. Local resident favored the culture heritage succession and evaluated its' usage Value highly. Visitors also have favored rural landscape offer function and evaluated inheritance value (Bequest Value) highly. Secondly, 80.5% of visitors, 78.1% of local resident have formed opinion about preservation of traditional stone fences. But the Willingness to pay for traditional stone fences fund was raised by 38.6% in local resident and 55.7% in visitor. The reason that willingness to pay does not exist is that it is chargeable to connection group and government, or it has no money to pay. Thirdly, local resident wanted to use made up stone fence preservation fund in rural landscape offer function. Visitor wanted that it is used to raise various function of stone fence.

• Journal of Advanced Marine Engineering and Technology
• /
• 제32권1호
• /
• pp.94-99
• /
• 2008

The characteristics of the flowfield of a square prism having fences on the corner was investigated by the PIV. Strouhal numbers, velocity vectors and velocity profiles around the square prism were observed at various positions of the fences, and Reynolds number of $Re=0.6{\times}10^4{\sim}1.0{\times}10^4$. As the results in case of the prism having fences the Strouhal numbers were all smaller than in case of the prototype prism. In case of the prism having vertical fences on the front corners the concentrated intensity of the vorticity was the strongest and the size of separated shear layer was the largest. While in case of the prism having vertical fences on the rear corners the concentrated intensity of the vorticity was the weakest and the size of separated shear layer was the smallest. Also in this case, the flow separated in front corner was reattached around the rear corner and made circulation.

• International Journal of Fluid Machinery and Systems
• /
• 제2권2호
• /
• pp.110-120
• /
• 2009

Generally the fluid flows within the centrifugal impeller passage as a decelerating flow with an adverse pressure gradient along the stream wise path. This flow tends to be in a state of instability with flow separation zones on the suction surface and on the front shroud. Hence several experimental attempts were earlier made to assess the efficacy of using boundary layer fences to trip the flow in the regions of separation and to make the flow align itself into stream wise direction so that the losses could be minimized and overall efficiency of the diffusion process in the fan could be increased. With the development of CFD, an extensive numerical whole field analysis of the effect of boundary layer fences in discrete regions of suspected separation points is possible. But it is found from the literature that there have been no significant attempts to use this tool to explore numerically the utility of the fences on the flow field. This paper attempts to explore the effect of boundary layer fences corresponding to various geometrical configurations on the impeller as well as on the diffuser. It is shown from the analysis that the fences located on the impellers near the trailing edge on pressure side and suction side improves the static pressure recovery across the fan. Fences provided at the radial mid-span on the pressure side of the diffuser vane and near the leading edge and trailing edge of the suction side of diffuser vanes also improve the static pressure recovery across the fan.

• 한국해양환경ㆍ에너지학회지
• /
• 제1권1호
• /
• pp.29-38
• /
• 1998

본 논문은 조류와 파랑중에서의 유벽의 성능에 관하여 저자들이 지난 수년간 수행한 연구 견과론 요약하여 수록하고 있다. 유벽의 성능 파악을 위해서 조류중 유벽의 누출개시 속도 예측, 파랑중 운동, 조류중 스커트의 변형에 관한 연구를 수행 하였다. 그 결과 해상 조건에서 유벽이 효과적인 보유 장비로서 활용되기 위해서는 그 보유 성능의 향상이 절대적으로 필요하다는 결론을 얻었다. 유벽의 보유 성능을 향상시키기 위한 한 방편으로 유벽을 이중으로 설치하는 방식의 효용성을 검토하였다. 연구를 통하여 동일한 형상의 유벽을 이중으로 적절히 설치함으로써 유벽의 보유 성능을 현격히 증대시킬 수 있다는 것을 입증하였다.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2005년도 학술발표회(1)
• /
• pp.330-332
• /
• 2005