An Experimental and Computational Study of the High-Velocity Impact of Low-Density Aluminum Foam

Abstract

The study presents the results of an experimental and computational study of the high-velocity impact of low-density aluminum foam into a rigid wall. It is shown that the aluminum foam samples deformed before hitting the rigid wall because of the high inertial forces during the acceleration. During the impact, the samples deformed only in the region contacting the rigid wall due to the high impact velocity; the inertial effects dominated the deformation process. However, the engineering stress–strain relationship retains its typical plateau shape until the densification strain. The experimental tests were successfully reproduced with parametric computer simulations using the LS-DYNA explicit finite element code. A unique computational lattice-type model was used, which can reproduce the randomness of the irregular, open-cell structure of aluminum foams. Parametric computer simulations of twenty different aluminum foam sample models with randomly generated irregular lattice structures were carried out at different acceleration levels to obtain representative statistical results. The high strain-rate sensitivity of low-density aluminum foam was also observed. A comparison of experimental and computational results during aluminum foam sample impact shows very similar deformation behavior. The computational model correctly represents the real impact conditions of low-density aluminum foam and can be recommended for use in similar high-velocity impact investigations.

Constitutive modeling and simulation of polyethylene foam under quasi-static and impact loading

“…Construction the strain rate term. According to equation (11), the density and temperature terms were not studied in this paper, the constitutive model with the strain rate is represented by equation ( 17):…”

“…[8][9][10] At present, most studies have focused on the mechanical properties of polymer foam under quasi-static compression (material strain rate: 10 À4 -10 À1 s À1 ) and high-speed impact (material strain rate will exceed 10 2 s À1 ) through universal material testing machine and the Hopkinson bar. [11][12][13][14][15] The strain rate of dynamic deformation caused by falling or collision during transportation of polymer foams is at intermediate strain rate, but a limited number of research have been on the mechanical properties of polymer foam within the range of intermediate strain rate (1 s À1 to 10 2 s À1 ). [16][17][18] Chen 16 obtained the dynamic mechanical characteristics of two kinds of expanded polystyrene (EPS) at intermediate strain rates of 2-280 s À1 using an INSTRON experimental machine.…”

Dynamic Response of Sandwich Tubes with Continuously Density-Graded Aluminum Foam Cores under Internal Explosion Load

“…Table 1 shows the material parameters of the Johnson–Cook model [ 28 ]. Because the aluminum foam is not sensitive to the strain rate effect, a simple model can be used; the bilinear elastic–plastic model was adopted as the matrix material: the density is 2730 , the Young’s modulus is 70 , Poisson’s ratio is 0.3, and the yield strength is 190 MPa [ 31 , 32 , 33 , 34 ]. The density of air is 1.293 , the MAT_NULL constitutive model was adopted, the pressure cutoff of air is −1.000 × 10 −12 [ 28 ], the state equation matching the constitutive model adopted EOS_LINEAR_POLYNOMIAL, and the pressure P in the equation of state is defined as a function of the internal energy density e and the relative volume v : …”

Crushing performance of auxetic tubes under quasi-static and impact loading

“…They concluded the inclination and declination of the plateau stress can be predefined by the specimen orientation. Matej Borovinšek et al [30] examined the lowdensity aluminum foam under high-velocity impact loading. They inferred the aluminum foam samples deform only in the region contacting the rigid wall during impact, due to the high impact velocity; the inertial effects dominate the deformation process.…”