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Aluminum foam structure is of great importance in aerospace, naval and automotive industries due to light weight and energy absorption characteristics. In this article several aluminum foam having different densities and thickness were designed and tested using light gas gun device. A series of ballistic test were defined in order to determine the effects of density, foam thickness and projectile velocity on energy absorption aluminum foam structures. The results of the experimental testes, it is shown that the amount of energy absorption of aluminum foam structures is increased as density, foam thickness and velocity of the projectile is increased.

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Sandwich panels(structures) of metal surface having aluminum foam core are of great importance in aerospace, naval and automotive industries due to high strength to weight ratio and high energy absorption characteristics. In this article several aluminum sandwich panels with aluminum foam core having different densities and thickness were designed and tested using light gas gun device. A series of ballistic test were defined in order to determine the effects of density, foam thickness and projectile velocity on energy absorption and ballistic limit velocity of sandwich structures. The material model used for metal foam was Deshpande- Fleck-Foam and coefficients were determined experimentally using foam and Matlab capabilities. Also, numerical simulation using LSDYNA software were performed. The results of the experiment and numerical simulation were compared and there was a good agreement between experimental investigation and numerical results. Using experimental testes and parametric studies,it is shown that the amount of energy absorption of sandwich structures is increased as density, foam thickness and velocity of the projectile is increased.

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Axial compression behavior of foam materials can be explained by two ideal deformation scenarios: discrete crush band process and progressive collapse. In this paper, a perfectly new model for strength assessment and quantitative/qualitative description of one-dimensional progressive collapse of aluminum foams under impulsive loadings is presented and its capability to split this way of crushing into two distinct regimes of shock wave and elastic- plasic wave propagation is highlighted. Then, using conservation relations and the new introduced model, the analytical solution of dynamic deformation of aluminum foams in the two mentioned regimes is developed. Regime 2 considers the case when the crushing front velocity is lower than the linear sound velocity of the foam; but remains higher than the effective sound velocity for a perturbation in which the amplitude lies in the so-called “plateau region’ of the static stress-strain diagram. The physical difference between this regime and the fiest one entails not only the creation a shock front associated with the collapsing foam, but also an acoustic precursor in the case of second regime.Finite element simulation is also performed to validate the analytical procedure. The numerical prediction is found to be in very good agreement with the analytical results.

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Hybrid laser-arc welding is a new welding process which received particular attention in various industries because of its technological and economic advantages. This process combines a laser beam and an electric arc to incorporate the advantages of both laser and arc welding processes. The main goal of this paper is to evaluate the performance and ability of hybrid Nd:YAG laser-TIG welding compared to lone laser welding process for welding of aluminum foam sandwich (AFS) panels of AA6082. For this aim, a set of experiments for both laser and hybrid laser-TIG welding were done to investigate the effects of welding parameters including laser power, arc current and welding speed on weld dimensions. Then, appropriate welding parameters for the laser and hybrid laser-TIG welding of AFS panels were calculated by statistical analysis. The results show that laser power threshold for creating the keyhole was less in hybrid laser-TIG welding than lone laser welding. Moreover, increasing the laser power and decreasing the welding speed result in increasing both the weld depth and width. But, with increasing the arc current, the weld depth remains almost unchanged and only the weld width increases. Comparing the laser and hybrid laser-TIG results show that adding a 100 A arc to a 2000 W laser source can increase the welding speed from 2 to 3 m/min which prove the high ability and efficiency of hybrid laser-TIG welding process.

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The unique properties of metal foams, including light weight, energy absorption, low thermal conductivity and recyclability, have led researchers to explore new ways to achieve these materials with a good relationship between properties and production costs. Different production methods are divided into two groups of liquid state and powder method based on the initial state of the metal. The aim of this study is to provide a new method for the production of open cell aluminum foam with Sodium Chloride spacer. Two different types of aluminum alloy with different fluidity were used to produce foam with this method. Pressure tests were performed to show the compressive behavior of aluminum foams. The results showed that the behavior of foams produced by this method is the same as the outcomes of other papers. In different densities, the behavior of the soft foam was the same, but the stress was higher in the same displacement for higher densities. In the same density for the two different alloys, the axial strength of the A332 alloy was higher, but in contrast the soft foam is a good energy absorber. Young's modulus for two types of alloys with identical densities was 1.45 GPa for the A332 alloy and 1.11 GPa for the 1067 alloy. The amount of energy efficiency decreased by densifying the foam.

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Slurry casting method is a novel process to produce metal forms, which makes it possible to produce a porous structure with open cell. In the present study, the microstructure and compressive behavior of aluminum foams produced by slurry casting method, under different number of immersion times were investigated. For the production of aluminum foams with different cell sizes, polyurethane preforms with characteristics of 45, 55 and 65 ppi were selected, and after immersing in a slurry having a solid mass of 88% and removing the excess semiliquid mixture, the samples were sintered at 630˚C. The size of polyurethane perform cell as well as the number of immersion times control the microstructure and compression performance of porous structures. The results of the study showed that the portability of porous aluminum increases by decreasing the size of preform cell or increasing the number of immersion times, which leads to thicker strut. In addition, the probability of crack existence, exactly at the corner of structures, decrease via enhancing the thickness of strut. Meanwhile, excessive increase in the number of immersion, i.e. third times, was associated with some closed-cells which results in strain localization and stress concentration. Therefore, the maximum plateau stress as well as the superior energy absorption capacity was observed in the sample having the minimum preform pore sizes which was immersed for two times in the aluminum slurry.