Numerical Modeling and Experimental Behavior of Closed-Cell Aluminum Foam Fabricated by the Gas Blowing Method under Compressive Loading

Abstract

This paper deals with the experimental and numerical study of closed-cell aluminum-based foam under compressive loading. Experimental samples were produced by the gas blowing method. Foam samples had an average cell size of around 1 mm, with sizes in the range 0.5–5 mm, and foam density of 0.6 g/cm3. Foam samples were subjected to a uniaxial compression test, at a displacement rate of 0.001 mm/s. Load and stress were monitored as the functions of extension and strain, respectively. For numerical modeling, CT scan images of experimental samples were used to create a volume model. Solid 3D quadratic tetrahedron mesh with TETRA 10-node elements was applied, with isotropic material behavior. A nonlinear static test with an elasto-plastic model was used in the numerical simulation, with von Mises criteria, and strain was kept below 10% by the software. Uniform compressive loading was set up over the top sample surface, in the y-axis direction only. Experimental tests showed that a 90 kN load produced complete failure of the sample, and three zones were exhibited: an elastic region, a rather uniform plateau region (around 23 MPa) and a densification region that started around 35 MPa. Yielding, or collapse stress, was achieved around 20 MPa. The densification region and a rapid rise in stress began at around 52% of sample deformation. The numerical model showed both compressive and tensile stresses within the complex stress field, indicating that shear also had a prominent role. Mainly compressive stresses were exhibited in the zones of the larger cells, whereas tensile stresses occurred in zones with an increased number of small cells and thin cell walls.

Aluminium Alloy Foam Modelling and Prediction of Elastic Properties Using X-ray Microcomputed Tomography

“…X-ray microcomputed tomography (µCT) allows the observation and study of the microstructure of foams and their virtual 3D representation, which has been the focus of most of the available research up until now [19]. However, its application combined with Finite Element Analyses (FEA) brings great potential and has been documented by some authors in varying degrees [11][12][13][14][15][16][17]20,21]. Through µCT scans, 2D projection images are obtained, in which each pixel represents the level of attenuation of X-rays during scanning on an 8-bit grey scale, i.e., from 0-255 or 256 different values of grey (2 8 = 256) [22].…”

“…The tests provide reassurance that the final 3D models are, in fact, correct and that the procedure of reconstruction and simplification was well done (Figure 6). Similar research has been done in order to acquire the 3D models for FEM simulation, however, the effects of the process were not investigated and few control variables were presented, such as the evolution of the mass or changes in the shape [11][12][13][15][16][17][18]. Hence, these topics are given a greater focus.…”

“…For that reason, here, X-ray micro computed Tomography (µCT) scans are used to construct 3D models to evaluate the mechanical properties of aluminium alloy foams, with special emphasis on the Young's modulus, which bring much more detail and result, in theory, in a more exact analysis when compared to analytical models or models that use artificial/approximated geometries [9]. These sorts of methods are commonly used in the medical field, material science, engineering and are being introduced in the field of cellular materials, despite the research on the topic still being limited and there being little standardization [10][11][12][13][14][15][16][17][18].…”

Correlation Modeling between Morphology and Compression Behavior of Closed-Cell Al Foams Based on X-ray Computed Tomography Observations

“…As a general observation, the more complex computational approaches based on FE modeling are hardly able to accurately simulate the whole spectrum of regimes that arise during the compression of cellular structures (linear elastic deformation, plastic collapse, densification), generally achieving greater accuracy in the second one, although there are examples in which a good fit of the experimental curve in the densification zone [31] or an acceptable agreement in the linear elastic region [32] is obtained.…”

Interval Identification of Thermal Parameters Using Trigonometric Series Surrogate Model and Unbiased Estimation Method

“…Islam et al [11] simulated the dynamic deformation of closed-cell foams structure by using the technology of X-ray tomography. Sharma et al [12] adopted CT scan technology to create a volume model and conducted corresponding experimental and numerical studies. Additionally, compared with periodic cells and CT scans, the Voronoi method was widely used to describe the random and complex mesostructure of the porous material factually [13][14][15].…”