جستجوی مقالات مرتبط با کلیدواژه "فوم آلومینیومی" در نشریات گروه "مکانیک"

In this study, a novel absorber design is presented to enhance performance over the conventional polymer variant in car bumpers. The new absorber adopts a sandwich structure with aluminum foam shells and a polymer foam core. Finite Element Method (FEM) and Abaqus software were employed, conforming to the E.C.E-R042 standard. Analysis indicates density has a more significant impact on performance than thickness. Across sandwich configurations, both maximum von Mises stress and plastic strain were significantly reduced compared to the polymer absorber. The maximum impact force, within a specified shell density range, was lower than the polymer counterpart. The optimal structure for maximum impact force, von Mises stress, and the plastic strain was determined using the Taguchi method. The selected item: sandwich absorber, 25mm shell thickness, and 225 kg/m³ density.

In this paper, the effect of geometry and addition of aluminum foam adsorbents on the energy absorption of nested thin-walled profiles under compressive axial load is investigated. ABAQUS commercial finite element software has been used for numerical analysis. The nested profiles are made of 6060-T5 aluminum material and the outer and inner profiles are considered with circular, square, hexagonal and octagonal cross sections. Force and displacement diagrams have been used to study the energy absorption rate of different nested geometries along with the calculation of total energy absorption and specific energy absorption. Finally, in order to investigate the effect of adding metal foam, three modes of adding aluminum foam to the nested profile under axial load were investigated. Nested thin-walled profiles absorb more energy when the foam is added than when hollow. In addition, the interaction between the foam walls and the pipe causes an additional increase in energy dissipation.

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.

Metal sandwiches are a new class of ultra-lightweight materials made from a porous metal core and two outer metal plates. High strength and high energy absorption capacity, resistance to heat, and also fast and inexpensive recyclability make these materials ideal for use in many industries including automotive, aerospace, oil, energy and construction industries. Considering the advantages of friction stir welding, the connection of these plates using this welding technology can be used industries for welding of bimetal sandwiches. In this research, feasibility of using frictional stir welding to prepare metal sandwiches with a core of aluminum foams and copper covers was investigated. The investigated parameters were tool rotational speed, in three levels of 2000, 2500 and 3000 rpm, and tilt angle in two levels of 5 and 7 degree. The cross-sections of the joints were investigated for weld quality which confirmed a successful joining. Tensile tests were carried out to evaluate the joint strength. It was concluded that the effect of tool rotational speed on the weld strength is much higher than the effect of tilt angle and has a reverse relation with tensile strength. The best strength which was 18.8 MPa was obtained with a tool rotational speed of 2000 rpm and a tilt angle of 5 degree.

In this paper, the specific absorbed energy (SAE) and mechanical properties of aluminum foam sandwich panels with composite surfaces under quasi-static loading were studied experimentally. The core of the samples are aluminum foam blocks with thicknesses of 1 cm, 2 cm and 3 cm. 2D-woven E-type glass fibers with surface density of 200 Kg/m2 and epoxy resin were used for fabrication of the surfaces. From adhesion of resin was used for bonding to the core and surface. the effect of changing the thickness and density of the core, the composite surface, the surface on one side of the core, the multilayered core having an equivalent thickness, the effect of changing the density of the aluminum foam core is studied and SAE values of the samples were compared. The results showed that increasing thickness of the aluminum foam from 2 cm to 3 cm increased the SAE between 12% and 26%. The use of composite surface reduces the amount of SAE. The multilayer core increased the SAE in the linear elastic zone and at the other force levels decreased the maximum of 6% of the SAE. Moreover, increasing the core density increased the degradation force and reduced the amount of displacement.

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.

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.