• Title, Summary, Keyword: Aluminum Foam

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A new concept for blast hardened bulkheads with attached aluminum foam

  • Kim, Sung-Ho;Woo, Heekyu;Choi, Gul-Gi;Yoon, Kyungho
    • Structural Engineering and Mechanics
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    • v.65 no.3
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    • pp.243-250
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    • 2018
  • The use of blast hardened bulkheads (BHBs) is an effective vulnerability hardening technique for improving the survivability of naval warships when internal explosions occur due to being shot by an anti-surface missile. In this paper, a new concept of BHBs reinforced by aluminum (Al) foam is proposed. The new concept can significantly reduce the blast pressures transferred to bulkheads and, unlike conventional BHBs, can be easily installed to operating naval warships. Chamber model blast tests were performed to demonstrate the effectiveness of the Al-foam BHBs and the results are further supported by numerical simulations. Finally, a practical preliminary is proposed for the Al-foam BHBs.

Heat Transfer and Flow Characteristics in an Annulus Filled with Aluminum Foam (발포 알루미늄이 삽입된 환형관에서의 열전달 및 유동특성)

  • Noh Joo-Suk;Han Young-Hee;Lee Kye-Bock;Lee Chung-Gu
    • Journal of Energy Engineering
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    • v.15 no.1
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    • pp.60-66
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    • 2006
  • An experimental investigation on the flow and convective heat transfer characteristics has been carried out far aluminum foam heat sink inserted into the annulus to examine the feasibility as a heat sink. Two aluminum foams or different permeability were selected to provide the friction factor and heat transfer correlations as function of Darcy, Reynolds and Prandtl number. Experimental results show that the friction factor is higher than clear annulus without aluminum foam, while $6\sim10$ times augmentation in Nusselt number is obtained. This technique can be used for the compactness of the heat exchanger.

Study of Al-Alloy Foam Compressive Behavior Based on Instrumented Sharp Indentation Technology

  • Kim Am-Kee;Tunvir Kazi
    • Journal of Mechanical Science and Technology
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    • v.20 no.6
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    • pp.819-827
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    • 2006
  • The stress-strain relation of aluminum (Al) alloy foam cell wall was evaluated by the instrumented sharp indentation method. The indentation in a few micron ranges was performed on the cell wall of Al-alloy foam having a composition or Al-3wt.%Si-2wt.%Cu-2wt.%Mg as well as its precursor (material prior to foaming). To extract the stress-stram relation in terms of yield stress ${\sigma}_y$, strain hardening exponent n and elastic modulus E, the closed-form dimensionless relationships between load-indentation depth curve and elasto-plastic property were used. The tensile properties of precursor material of Al-alloy foam were also measured independently by uni-axial tensile test. In order to verify the validity of the extracted stress-strain relation, it was compared with the results of tensile test and finite element (FE) analysis. A modified cubic-spherical lattice model was proposed to analyze the compressive behavior of the Al-alloy foam. The material parameters extracted by the instrumented nanoindentation method allowed the model to predict the compressive behavior of the Al-alloy foam accurately.

Mechanical Properties of the Foamed Aluminum According to the Quantity of Calcium (칼슘 첨가량에 따른 발포 알루미늄의 기계적 성질)

  • Do Bok-Hwan;Kim Joo-Hyun
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.1
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    • pp.113-118
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    • 2006
  • In this work, we observed the changes in mass difference according to Al-foam's amount of Ca contents which depends on the viscosity control of fusion, quality of foamed addition, mixing, temperature tests. These are crucial influencing factors in determining foam-metal's size in the manufacturing process. In order to obtain the specimen, we changed the specific gravity from 0.2 to 0.3 for the study of the light weight, and obtained the optimal values of specific gravity, and then showed the mechanical characteristics of ultra-lightweight metal according to the changing mass. The optimal conditions for aluminum foam is when the addition of Ca content in $1.5wt\%~2.0wt\%$

Compressive Properties of Open Cell 6063 Aluminium Foam (개포형 6063 발포 알루미늄의 압축특성)

  • Bu, Sung-Duk;Kang, Bok-Hyun;Kim, Ki-Young
    • Journal of Korea Foundry Society
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    • v.27 no.1
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    • pp.36-41
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    • 2007
  • Compressive properties of the open cell 6063 aluminum alloy foams made by the plaster molding process were investigated before and after heat treatment. Loading process was controlled at a displacement rate of 2 mm/min. Compressive strength of 10 PPI foam was the largest of the same density foams. Increase in strength after heat treatment for the bulk material was remark able, however was not for the 6063 aluminum foam. C values were in the range of $0.39{\sim}0.53$ for as cast foams and $0.13{\sim}0.16$ for T6 heat treated foams in the equation of ${sigma}^*_{pl}/{\sigma}_{ys}=C({\rho}/{\rho}_{s})^{1.5}$ and increased with cell size.

Crashworthiness Design Concepts for the Improved Energy Absorbing Performance of an Aluminum Lightweight Vehicle Body (알루미늄 경량 차체의 충돌에너지 흡수 성능 향상을 위한 설계 개선 연구)

  • 김범진;허승진
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.3
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    • pp.155-160
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    • 2003
  • For the weight reduction of vehicle body up to 20∼30% compared to the conventional monocoque steel body·.in-white, most automotive manufacturers have attempted to develop the aluminum intensive body-in-white using an aluminum space frame. In this paper, the crush tests and simulations for the aluminum extrusions filled with the structural from are performed to evaluate the collapse characteristics of that light weighted material. From these studies. the effectiveness of structural for is evaluated in improving automotive crashworthiness. In order to improve the improve energy absorption capability of the aluminum space frame body, safety design modifications are performed and analyzed based on the suggested collapse initiator concepts and on the application of the aluminum extrusions filled with structural foam. The effectiveness of these design concepts on the frontal and side impact characteristics of the aluminum intensive vehicle structure is investigated and summarized.

A Numerical Study on Beat Transfer from an Aluminum Foam Heat Sink by Impinging Air Jet in a Confined Channel (충돌 공기제트에서 국한 유로 내 발포 알루미늄 방열기의 열전달 수치해석)

  • Lee, Sang-Tae;Kim, Seo-Young;Lee, Kwan-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.26 no.6
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    • pp.883-892
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    • 2002
  • A numerical study has been carried out to investigate the flow and heat transfer from an aluminum foam heat sink in a confined channel. A uniform heat flux is given at the bottom of the aluminum foam heat sink, which is horizontally placed on the heated surface. The channel walls are assumed to be adiabatic. Cold air is supplied from the top opening of the channel and exhausted to the channel outlet. Comprehensive numerical solutions are acquired to the governing Wavier-Stokes and energy equations, using the Brinkman-Forchheimer extended Darcy model and the local thermal non-equilibrium model f3r the region of porous media. Details of flow and thermal fields are examined over wide ranges of the principal parameters; i.e., the Reynolds number Re, the height of heat sink h/H, porosity $\varepsilon$and pore diameter ratio $R_{H}$.

An Experimental Study on the Thermal Resistance Characteristics for Various Types of Heat Sinks (다양한 형상의 Heat Sink 열저항 특성에 관한 실험적 연구)

  • 김종하;윤재호;이창식
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.8
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    • pp.676-682
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    • 2002
  • This paper has been made to investigate the thermal performance characteristics for the several types of heat sinks such as extruded heat sink, aluminum foam heat sink, layered heat sink. The various types heat sinks are prepared and tested for natural convection as well as forced convection. The experimental results for natural convection are compared to those for three types of heat sink so that the appropriate heat sink can be designed or chosen according to the heating conditions. The overall heat transfer performances for layered heat sink, extruded heat sink and aluminum foam heat sink are almost comparable to those under natural convection and forced convection. The forced convection of layered heat sink become 1.2 times as high as those of extruded heat sink, and the forced convection of extruded heat sink become 1.2 times as high as those of aluminum foam heat sink. This study shows that bar height, bar distance and number of bar for layered heat sink are important parameters, which have a serious influence on thermal performance for layered heat sinks.

Effect of Foaming Temperature on Cell Structure of 606X Series Aluminum Alloy Metallic Foams (Foaming 온도에 따른 606X계 발포 알루미늄의 제조 특성)

  • Song, Yeong-Hwan;Park, Soo-Han;Jeong, Min-Jae;Kang, Kwang-Jung;Hur, Bo-Young
    • Journal of Korea Foundry Society
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    • v.28 no.2
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    • pp.79-84
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    • 2008
  • Metal foam is one of the most interesting materials with various multi-functional properties such as light weight, energy absorption, high stiffness and damping capability. Among them, energy absorption property has keen interests in the field of automotives for passenger protection. Nowadays, researches about pore size and porosity control of the foam are increased to correspond them. However, though energy absorption properties are improved, these results are not cost-effective process. In present research, however, as a part of improving the energy absorption property of metallic foams, 606X aluminum alloy was used for cell wall material which has higher strength than pure aluminum. And its morphological features are characterized. As a results, porosity and pore size are uniformity distribution with increasing foaming temperature in the case of 6061 alloy foams. 6063 alloy foam specimens have opposite tendency because of the influence of alloying element and viscosity of the molten melt.

Study on Structural Analysis of DCB Specimen Bonded with Aluminum Foam Composite (알루미늄 폼 복합재료로 된 접합된 DCB 시험편의 구조 해석에 관한 연구)

  • Choi, Hae-Kyu;Kim, Sei-Hwan;Cho, Jae-Ung
    • 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.