• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.1
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• pp.11-23
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• 2010

A sacrificial member with aluminum foam of excellent energy absorption capacity was proposed for the protection of significant structures. Parametric studies of explicit finite element analyses were performed to investigate the pressure mitigation of close-range air-blasts. The scaled distance of the blast had a range of Z=0.48~0.95 and an empirical blast load function was utilized. The analytical parameters of the aluminum foam were density, thickness and the existence of a cover sheet. Analytical results showed that the transmitted pressure can be controlled to have a similar level of yield values of the foam by using a foam with low density and higher thickness. As the blast load increased, the sacrificial member needed to have higher density and thickness. A cover sheet of the foam clearly showed its effect on the wider distribution of blast pressure. It is necessary to determine the design parameters of sacrificial foams considering different energy dissipation capacities according to the scaled distance.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.388-393
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• 2004

A comprehensive numerical study on the three point bending behavior of Aluminum foam-filled stainless steel tube has been performed. Aluminium alloy foams with various densities were produced and their mechanical properites were evaluated. Finite element(FE) analysis of three point bending test was performed to evaluate bending behavior of foam filled cylindrical structures. Results showed that foam filling offered remarkable increase of bending resistance and enhanced the crashworthiness of the structure. It turned out to prevent the inward fold formation at the compression flange, resulted into the multiple propagating folds and increased the load carrying capacity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1488-1495
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• 2012

In this study, the fracture behaviour of DCB(double cantilever beam) specimen with aluminum foam composite materials is analyzed by simulation. The used model is 3D configuration on the basis of British industrial standard and ISO international standard. As the thickness of model is increased, the length of propagated crack is increased and the load becomes higher. The analysis result obtained by this study can be applied at the practical composite structure bonded with aluminum foam materials. The fracture behaviour is analyzed and the mechanical property can be understood.

• Resources Recycling
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• v.15 no.2 s.70
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• pp.18-23
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• 2006

Foaming of slag is a thermodynamically unstable phenomenon and has significant effects in iron and steelmaking processes. For better recycling method of pulp sludge, the application as an defoaming agent during steelmaking process was adopted and tested. The forming machine has been modified in order to produce the briquettes, which are made of pulp sludge and slag with different weight ratio. Influencing factors on the foaming phenomena have been studied and tested for better understanding of foaming phenomena. Experiments were carried out with $CaO-FeO-SiO_2$ based slags with Ar gas injection and addition of coke particles. The slag basicity and (%FeO) contents adapted as major factors to treasure foaming tendency of the slag system. It was found that foam index (${\Sigma}$) gradually decreased as both the basicity and the (FeO) content increase. Four kinds of antifoaming agent such as aluminium dross, cokes, rice bran and pulp sludge with steelmaking slag have been tested in actual process. Aluminium dross was the most effective, and pulp sludge with steelmaking slag also showed the desired results.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.18.1-18.1
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• 2009

금속 다공체는 자동차, 선박, 건축 등의 분야에서 구조물이나 충격흡수제 등으로 응용되고 있는데 이들은 일반 금속 구조물에 비해 가볍고 플라스틱에비해서는 강한 장점을 지닌다. 현재 사용되고 있는 대부분의 금속 다공체는 발포 주조공정으로 제조된 알루미늄으로서, 철계 합금에 비해 가벼운 장점을 갖지만 강도가 상당히 떨어지고 가격이 높은 단점을 가진다. 따라서 본 연구에서는 알루미늄 대신 철계 합금으로 다공체를 제조하고자 하였고 제조방법으로는 주조공정 대신 분말공정을선택하였다. 분말공정은 구형 스티로폼을 금속분말 슬러리로 코팅한 후 스티로폼을 제거하여 낱개의 금속중공체(Metallic Hollow Sphere)를 제조하고 이렇게 제조된 중공체를 뭉쳐 성형함으로써최종 형상의 다공체를 제조하는 방법이다. 이 방법으로 제조된 다공체는 주조공정으로 제조된 다공체보다높은 강도를 나타내며 낱개의 중공체는 성형공정을 거치지 않고 필터나 충진재 등의 새로운 용도로 활용될 수 있다.

• Proceedings of the KAIS Fall Conference
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• 2011.05b
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• pp.844-846
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• 2011

충돌에서의 차체 손상과 충돌 성능 강화를 위하여 최근 크래쉬 영역의 개념이 설계개념에 도입되고 있다. 대표적인 예가 범퍼와 차체사이의 크래쉬 박스로 저속충돌시 충격에너지를 흡수하여 범퍼이후 차체에 에너지를 저감시켜 차량의 안전성 및 수리비 저감 등에 있어서도 매우 효과적인 역할을 하는 부품으로 이에 대한 개발을 위해 많은 연구들이 진행되고 있다. 본 논문에서는 충돌에너지 흡수성능이 우수한 크래쉬박스에 알루미늄 폼을 적용하였을 때 충돌에너지 흡수 및 거동에 대하여 충돌해석을 수행하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.582-585
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• 2012

The aluminum extruded panel used for a high speed train shows the largest contribution to sound insulation performance of the train body. However, comparing with the flat panel having the same weight, the transmission loss falls sharply in the local resonance frequency band. Such fall of transmission loss can be improved by increasing the damping of local resonance. This study examines the charging effect of an urethane foam on the aluminum extruded panel of a high speed train. We charged the urethane foam with different mass density and in different way in the core part of the extruded panel. We measure the transmission loss and compare the sound insulation performance according to the density and charging method. Finally, Improvement effect of the transmission loss is compared and analysed in aspect of weight increment.

• Korean Journal of Construction Engineering and Management
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• v.14 no.3
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• pp.115-122
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• 2013

Construction Standard Productivity Manual (CSPM) has been used for estimating the contract amount of public construction projects. CSPM has been annually either revised and/or newly enacted with high costs. Therefore, This study makes use of CYCLONE, which is a simulation modeling and analysis system specialized in construction operation, to improve the revising and enacting processes of CSPM. This paper presents the CSPM revision module that is an Add-in to Web-CYCLONE. The new module can be effectively used to incorporate the auxiliary tasks and the non-productive tasks into AL-Form operation model. The outputs obtained from the models using he CSPM revision module and from work sampling were compared to verify the usability of the add-in modules. This study verifies that the new module can effectively assist enacting and/or revising CSPM.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.187-187
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• 2010

최근 해상풍력 블레이드가 대형화됨에 따라 보다 가볍고 강한 재료가 요구되고 있다. 현재 주로 사용되고 있는 복합재는 발사우드나 PVC 폼 등을 코어소재로 하고, 유리섬유나 탄소섬유 등을 보강섬유로 사용하고 있다. 본 연구에서는 현재 사용되고 있는 복합재에 대한 특성을 알아보고, 최근 흡음, 충격 및 열에 강한 발포 알루미늄을 이용한 복합재를 해상풍력 블레이드 제조에 적용하여, 구조 강도 실험을 실시함으로써 기존 복합재와 구조 강도 및 비용 등을 비교 검토하여 우수한 복합재를 제시하고자 한다. 이를 위해 대형구조물인 블레이드를 제작하기 위해 적절한 크기의 발포 알루미늄을 상호 접합하기 위한 방법을 연구하고자 하며, 목포대학교에서 보유중인 만능재료시험기(100 Ton)를 활용하여 인장, 압축, 굽힘 실험을 실시하고, 스킨재 변화, 코어재의 밀도와 두께 변화를 고려하여 다양한 복합재의 강도를 비교하고자 한다. 또한, 기존에 사용되고 있는 복합재와 발포 알루미늄을 이용한 복합재의 재료비 및 가공비를 추정하고 경제적인 복합재를 제시하고자 한다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.4
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• pp.545-560
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• 2019

During EPB TBM tunnelling, an appropriate application of additives such as foam and polymer is an essential factor to secure the stability of TBM as well as tunnelling performance. From the '90s, there have been many studies on the optimal injection of additives worldwidely contrary to the domestic situation. Therefore, in this paper, the foam, which is widely adopted for soil conditioning, was selected as an additive in order to investigate the effect of foam injection on TBM performance through a series of laboratory excavation tests. The excavation experiments were carried out on artificial sandy soil specimens with consideration of the variance of FIR (Foam Injection Ratio), FER (Foam Expansion Ratio) and $C_f$ (Surfactant Concentration), which indicate the amount and quality of the foam. During the tests, torque values were measured, and the workability of conditioned soil was evaluated by comparing the slump values of muck after each experiment. In addition, a weight loss of the replaceable aluminum cutter bits installed on the blade was measured to estimate the degree of abrasion. Finally, the foam injection ratio for the optimal TBM excavation for the typical soil specimen was determined by comparing the measured torque, slump value and abrasion. Note that the foam injection conditions satisfying the appropriate level of machine load, mechanical wear and workability are essential in the EPB TBM operational design.