Papers by Keyword: Aluminum Foam

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Authors: Attanadol Prapajaraswong, Seksak Asavavisithchai
Abstract: Al foam is an advanced engineering material with many outstanding properties, such as very low density, high specific strength and stiffness, and large energy absorption. In the present study, pure Al foams were mixed with either cenosphere or precipitator fly ash particles of various contents. Fly ash particles are used in Al foams as reinforcement and stabilising materials which enable the foams with large expansion. It is found that Al foams with precipitator fly ash particles of various contents exhibited larger expansions than the foams with cenosphere fly ash particles. The quantitative analysis also revealed that more stable foam structure was obtained in Al foams with precipitator fly ash addition.
89
Authors: Yu Jie Liu, Bin Qiang
Abstract: Based on the obtained experimental results, the features of stress-strain behavior of the metallic foam were discussed firstly in this paper. Then, in the framework of 2M1C visco-plasticity constitutive model, a cyclic constitutive model was proposed to simulate the stress-strain responses under monotonic and cyclic compression. In proposed model, plastic strain is divided into two parts, i.e., plastic strain of matrix metal and plastic strain of voids structure, which are associated with relative density. Additionally, a kinematic hardening rule of yield surface center is used to describe ratchetting effect during cyclic loading. The simulated stress-strain responses of aluminum foam are in a good agreement with the experimental ones.
285
Authors: C. Mahesh, Anindya Deb, S.V. Kailas, C. Uma Shankar, T.R.G. Kutty, K.N. Mahule
Abstract: The characterization of a closed-cell aluminum foam with the trade name Alporas is carried out here under compression loading for a nominal cross-head speed of 1 mm/min. Foam samples in the form of cubes are tested in a UTM and the average stress-strain behavior is obtained which clearly displays a plateau strength of approximately 2 MPa. It is noted that the specific energy absorption capacity of the foam can be high despite its low strength which makes it attractive as a material for certain energy-absorbing countermeasures. The mechanical behavior of the present Alporas foam is simulated using cellular (i.e. so-called microstructure-based) and solid element-based finite element models. The efficacy of the cellular approach is shown, perhaps for the first time in published literature, in terms of prediction of both stress-strain response and inclined fold formation during axial crush under compression loading. Keeping in mind future applications under impact loads, limited results are presented when foam samples are subjected to low velocity impact in a drop-weight test set-up.
64
Authors: A. Adamčíková, B. Taraba, J. Kováčik
Abstract: Aluminium foam is a unique material possessing very high thermal diffusivity due to high thermal conductivity of the cell walls accompanied with rather low overall thermal conductivity, controlled via porosity [1]. There is a presumption of increasing influence at thermal diffusivity of aluminium foam by decreasing porosity, following the presented results (e.g. by using the transient plane source method [2]) and relation between thermal diffusivity and density. Thermal diffusivity of aluminium foam considering various porosity and various compositions of precursors were observed. The Aluminium foam was prepared by the powder metallurgy route, also well known as the ALULIGHT process, and various densities were achieved by changing of parameters (temperature, time) of foaming. The following types of foamable precursors were used: AlMg1Si0.6, AlSi10, as blowing agent was used 0.8 wt. % of TiH2.The thermal diffusivity of particular precursors by the flash method was measured. Specific heat capacities of samples with different density were measured by a calorimeter for various temperatures. The coefficient of thermal conductivity as a function of temperature was calculated by heat transient experiment data and numerical simulation consequently as an inverse heat transfer task. The problem was solved by the finite element method using the engineering-scientific program code ANSYS. The results depend on the thermal diffusivity, on the porosity and the type of precursor. Despite that aluminium foam is considered as a type of composite, thermophysical properties could be calculated upon known volume of aluminium alloy and air in the pores However there is a presumption that this rule cannot be used in case of porous materials. Values obtained by the mentioned methodology shown a significant influence on the porosity and the thermal diffusivity of the aluminium foam.
814
Authors: Ji Lin Yu, Er Heng Wang, Liu Wei Guo
Abstract: The phenomenological constitutive framework for compressible elasto-plastic solids presented by Chen and Lu [1] is extended to the dynamic cases by assuming that the material parameter curves in the stress potential depend also on the strain rate. To check the applicability of the extended model, three types of dynamic experiments, i.e., uniaxial compression, lateral-constrained compression and side-constrained compression tests, are conducted for an open-cell aluminum foam at different strain rates. The first two types of dynamic tests are used as characteristic tests to determine the material parameter curves at different strain rates which are then used to construct the stress potential function in the model. The results show that the stress-strain curves under side-constrained compression predicted by the model are in agreement with those obtained experimentally.
1878
Authors: Joyjeet Ghose, Vinay Sharma, Surender Kumar
Abstract: Experimental investigation of sound absorption characteristics of aluminium foam is carried out under laboratory test conditions. The studies revealed that the developed aluminium foam have excellent sound absorption properties and is comparable with other sound absorbing materials. Excellent sound absorption property coupled with good mechanical properties makes this material ideal for sound absorption under difficult situations. Experimental results revealed that the thickness of the specimen affects the sound absorption properties of the material, and there exists an optimal thickness, at which sound absorption coefficient is maximum. Experimental evidence showed that presence of damaged cell edges, open and/or semi-open cells in the specimen surface, enhances the sound absorption capability of the material.
1145
Authors: Huai Qian Bao, Chang Tian Wang, Jun Li
Abstract: The common reactive muffler has poor acoustic properties in high frequency, so aluminum foam is applied to the reactive muffler and the impendence compound muffler is designed. The acoustic performance of the muffler is analyzed; the interior sound field of the muffler is modeled and meshed in the ANSYS, then they are imported into SYSNOISE, and imposed reasonable boundary conditions to carry out the analysis of acoustic performance of the muffler. The results show that, compared to reactive muffler, the muffler with aluminum foam has a higher amount of noise reduction and a wider frequency band in middle and high frequency.
253
Authors: Hong Jie Luo, Hao Lin, Jian Kun Zhang, Guang Chun Yao
Abstract: Two basic methods can be used to fabricate aluminum foam. One is powder metallurgy route which can provide the near net shape casting containing aluminum foam core, and the other is melt foaming route which can prepare large scale aluminum foam plate directly. To combine the advantages of above two methods, the precursor was obtained through melt foaming route and then baked in a furnace like that of powder metallurgy method in this investigation. The test results indicated that the SiC and TiH2 particles after treatment in air could be dispersed in Al-Si matrix alloy melt and the precursors were obtained. The porosity and their pore diameter of the precursors decreased along with the temperature reducing as well as the magnesium or SiC particles adding. The density of Al-Si alloy foam decreased with the elevation of baking temperature and extension of heating time before collapse of foam block occurred. The foaming process parameters were seriously affected by the aluminum alloy composition.
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Authors: Qing Zhen Li, Zhong Hua Du, Kang Kang Wang
Abstract: To study spacecraft shield structure against hypervelocity impact of space debris and its protective performances, 25mm ballistic gun launching 12.7mm cylindrical debris is selected against Aluminum foam composite structure at high speed. Based on the experimental results and analyze the effects of Aluminum foam protective structure with different combinations, the result is that protective effects with Aluminum foam in front of glass fiber is better.
20
Authors: J.A. Reglero, Miguel A. Rodríguez-Pérez, D. Lehmhus, M. Windmann, Jose A. de Saja, A. Fernández
Abstract: A collection of AlSi7 closed cell foams were fabricated following the powder metallurgical route [1,2], reaching densities between 540 Kg/m3 and 1350 Kg/m3. Thermal conductivity of the samples was determined using the Transient Plane Source technique (TPS) [3,4], and influence of density was estimated. Several models were tested, and the correlation between experimental data and theoretical results was evaluated. Finally, measurements in different directions were performed, revealing the use of the TPS technique as a non-destructive tool to investigate the existence of in-homogeneities derived from the foaming process.
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