• Journal of the Korean Wood Science and Technology
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• 제45권5호
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• pp.640-649
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• 2017

목조건축의 기반을 넓히고 소비자의 만족도를 향상시키기 위해 기존의 일반목조벽체 및 기타 경량목조벽체에 대한 비교 연구가 필요하다. 따라서 본 연구에서는 일반벽체와 개선된 방식인 교호 샛기둥 벽체와의 성능 비교를 통해 새로운 가능성을 찾고자 하였다. 우선 교호 샛기둥 벽체의 강도적 특성을 평가하고 일반벽체의 강도적 특성을 비교하였다. 일반벽체를 구성하는 목재의 단면이 교호 샛기둥 벽체보다 크기 때문에 일반벽체의 최대하중이 교호 샛기둥 벽체 보다 크게 나타났다. 하지만, 두 그룹간의 통계분석에 의하면 95% 신뢰 수준에서 유의성을 보이지 않아, 교호 샛기둥 벽체는 일반벽체를 대체할 수 있는 가능성을 보여주었다. 교호 샛기둥 벽채는 샛기둥의 단면이 일반벽체보다 작기 때문에 재료를 절약할 수 있어서 일반벽체보다 더 경제적이라고 판단된다. 또한 단열재의 면적 또한 증가하므로 열교 현상의 개선도 기대된다.

• 비파괴검사학회지
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• 제22권6호
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• pp.621-626
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• 2002

The amplitude of a back-wall echo depends on the reflection coefficient of the interface between a transducer and a test material when using contact pulse-echo ultrasonic testing. A couplant is used to transmit ultrasonic energy across the interface, but has an influence on the amplitude of the pulse-echo signal. To investigate the couplant effect on pulse-echo ultrasonic testing, back-wall echoes are measured by using various couplants made of water and glycerine in a carbon and austenitic stainless steel specimens. The amplitude of the first back-wall echo and the apparent attenuation coefficient increases with the acoustic impedance of the couplant. The couplant having a higher value of the transmission coefficient is more effective for flaw detection. The reflection coefficient should be known in order to measure the attenuation coefficient of the test material.

• 대한치과의사협회지
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• 제48권4호
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• pp.263-274
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• 2010

I classified the bone graft material according to the component. Most bone graft material is composed of inorganic and organic constituent. Organic component such DBM is associated with osteoinduction. Inorganic components such as hydroxyapatite, $\beta$-TCP, calcium sulfate, bioactive glass, polymer are associated with osteoconduction. Autogenous bone graft is ideal material. We can select any biocompatible material for the restoration of small filling defect with intact bony wall. However, we should select first osteogenetic and osteoinductive material to regenerate the viable bone tissue.

• Structural Engineering and Mechanics
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• 제1권1호
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• pp.1-16
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• 1993

The behavior of shear-wall dominant, low-rise, multistory reinforced concrete building structures is investigated. Because there are no beams or columns and the slab and wall thicknesses are approximately equal, available codes give little information relative to design for gravity and lateral loads. Items which effect the analysis of shear-wall dominant building structures, i.e., material nonlinearity including rotating crack capability, 3-D behavior, slab-wall interaction, floor flexibilities, stress concentrations around openings, the location and the amount of main discrete reinforcement are investigated. For this purpose 2 and 5 story building structures are modelled. To see the importance of 3-D modelling, the same structures are modelled by both 2-D and 3-D models. Loads are applied first the vertical then lateral loads which are static equivalent earthquake loads. The 3-D models of the structures are loaded in both in the longitudinal and transverse directions. A nonlinear isoparametric plate element with arbitrarily places edge nodes is adapted in order to consider the amount and location of the main reinforcement. Finally the importance of 3-D effects including the T-C coupling between walls are indicated.

• 헤리티지:역사와 과학
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• 제54권4호
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• pp.4-21
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• 2021

본 연구는 조선시대 건축 공사 기록인 영건의궤에서 조선 후기 건물에 구성되었던 벽의 명칭과 유형을 살펴보고, 종묘 정전과 영녕전에 사용된 벽에 대해 고찰하는 데 그 목적이 있다. 연구의 결과는 다음과 같다. 첫째, 벽의 명칭은 성격에 따라 방향·위치, 형상·기능, 재료, 복합 등 네 가지 유형으로 구분할 수 있으며 벽 앞에 성격을 의미하는 단어가 합쳐진 합성어로 사용되었다. 둘째, 벽의 유형 중 재료와 관련된 일부 벽은 사용 시기에 차이가 있음이 확인되었다. 18세기 이후 토벽의 사용은 줄고 목벽(판벽), 지벽의 사용이 많은 것으로 확인된다. 셋째, 종묘 정전과 영녕전의 벽은 흙벽과 화방벽이 사용되었으며, 고주열 중인방 상부는 흙벽으로, 외부는 화방벽으로 구성되었다. 화방벽은 종묘 정전의 경우 기둥까지를 포함한 일체화된 모습으로 설치된 반면, 영녕전의 경우는 기둥과 기둥 사이에만 설치되었다. 넷째, 갑벽은 의궤 내 사용된 용례들과 현재 건물의 비교를 통해 '종묘 내 건축물 구성 시 사용된 중인방 상부에 설치한 벽'으로 정의할 수 있다. 본 연구는 익숙한 까닭에 연구가 미비했던 벽을 중심으로 조선 후기에 사용되었던 벽의 명칭들과 용례를 기록과 실제 건물의 비교를 통해 살펴보고 갑벽의 정의를 밝히기 위해 시도하였다는 점에 의의를 둘 수 있다.

• Steel and Composite Structures
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• 제26권1호
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• pp.1-15
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• 2018

This study reported, the effect of random variation in system properties on bending response of single wall carbon nanotube reinforced composite (SWCNTRC) plates subjected to transverse uniform loading is examined. System parameters such as the SWCNT armchair, material properties, plate thickness and volume fraction of SWCNT are modelled as basic random variables. The basic formulation is based on higher order shear deformation theory to model the system behaviour of the SWCNTRC composite plate. A C0 finite element method in conjunction with the first order perturbation technique procedure developed earlier by the authors for the plate subjected to lateral loading is employed to obtain the mean and variance of the transverse deflection of the plate. The performance of the stochastic SWCNTRC composite model is demonstrated through a comparison of mean transverse central deflection with those results available in the literature and standard deviation of the deflection with an independent First Order perturbation Technique (FOPT), Second Order perturbation Technique (SOPT) and Monte Carlo simulation.

• 소성∙가공
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• 제19권8호
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• pp.508-516
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• 2010

Thickening process in sheet metal forming is being increased to improve the strength as well as to reduce manufacturing process such as welding. This process can make it possible to obtain part locally thicker than that of initial sheet thickness. In this study, design method for manufacturing the component which has double sinks with local thickened wall is proposed. Deep drawing and upsetting processes are applied in order to form double sinks and thicken its walls. Used material is SPHC440 with the thickness of 2.0mm and initial blank size is determined on the basis of the final product. Distance between the center of double sinks and first drawing ratio to avoid fracture are the most significant factors during deep drawing. FE-analysis is implemented in order to determine the appropriate values. Progressive die is designed based on the proposed method and FE-analysis. As a result of experiment, locally thickened component can be manufactured, which has double sinks with the thickness about 3mm at the corner and wall.

• 보존과학연구
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• 통권29호
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• pp.255-278
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• 2008

Considering the physical quality of the wall body in this study we tried to select a replenishing that is proper for filling the cracked part of the painting wall layer and apply the natural adhesives that have traditionally been used, investigating whether it is possible to substitute those for the chemical adhesive which is used at present time. The result of this study showed the red algae adhesive was, in a weathering environment, as safe as the synthetic resin originated from the polyvinyl acetate which is used generally on the present spot, and it was concluded that although the starch adhesive displayed its superiority in enhancing the strength of the earth mortar and its work disposition, it seemed proper for it to be used as a filling adhesive for the first or midterm layer because it showed a surface hardening phenomenon. And also the glue and fish glue were judged they were not qualified as a filling adhesive due to mold occurring in a environment of high moisture that is a biological problem, showing at same time a weak physical feature in a weathering environment. Therefore it would be possible to use the red algae adhesive or starch one substituting them for the original one sold on the present market, if among natural adhesives the weak points of the them were to be corrected.

• Structural Engineering and Mechanics
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• 제64권2호
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• pp.183-194
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• 2017

This paper presents the experimental investigation into a new type of steel-concrete hybrid outrigger system developed for the high-rise building structure. The steel truss is embedded into the reinforced concrete outrigger wall, and both the steel truss and concrete outrigger wall work compositely to enhance the overall structural performance of the tower structures under extreme loads. Meanwhile, metal dampers of low-yield steel material were also adopted as a 'fuse' device between the hybrid outrigger and the column. The damper is engineered to be 'scarified' and yielded first under moderate to severe earthquakes in order to protect the structural integrity of important structural components of the hybrid outrigger system. As such, not brittle failure is likely to happen due to the severe cracking in the concrete outrigger wall. A comprehensive experimental research program was conducted into the structural performance of this new type of hybrid outrigger system. Studies on both the key component and overall system tests were conducted, which reveal the detailed structural response under various levels of applied static and cyclic loads. It was demonstrated that both the steel bracing and concrete outrigger wall are able to work compositely with the low-yield steel damper and exhibits both good load carrying capacities and energy dispersing performance through the test program. It has the potential to be applied and enhance the overall structural performance of the high-rise structures over 300 m under extreme levels of loads.

• 한국해양공학회지
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• 제29권1호
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• pp.62-69
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• 2015

Coastlines are protected by breakwater structures against the erosion of sand or other materials along beaches due to wave action. This research examined the use of physical modeling to determine the effects of the tetrapod size and vertical walls of a rubble mound on the volume of wave overtopping under irregular wave conditions in coastal areas in Busan Yacht Harbor. In this analysis model, the structures were studied using irregular waves and the JONSWAP wave energy spectrum. To understand the effects of the tetrapod size and heights of the vertical wall, the study considered vertical walls of 0, 1.78, 6.83, and 9.33 cm with armor double layered material tetrapods of 8, 12, 16, and 20 tons. An extensive number of experiments covering a relatively large range of variables enabled a comprehensive discussion. First, in the presence of a short vertical wall, the water level played a key role in the overtopping discharge. In such circumstances, the values of the wave overtopping discharge decreased with increasing freeboard size. In the presence of a tall freeboard and middle, the value of the wave overtopping discharge was equally influenced by the vertical wall factor. Moreover, the tetrapod size decreased by an increase in the vertical wall factor, and relationship between them resulted in a short wall height. From an engineering point of view, considering a small water level may allow the choice of a shorter vertical wall, which would ultimately provide a more economical design.