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

Matej Borovinšek,Matej Vesenjak,Zoran Ren,Kazuyuki Hokamoto

doi:10.3390/ma13081949

Matej Borovinšek, Matej Vesenjak + Show 2 more

Open Access

https://doi.org/10.3390/ma13081949

Copy DOI

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.

Highlights

Lightweight materials have unique physical and mechanical properties, such as low density and high specific stiffness, and are being increasingly used in modern industrial applications [1]
The images demonstrate that the aluminum foam samples deform onlyonly in in region the region contacting rigid to high impact velocity; inertial effectsdominate dominatethe the the contacting the the rigid wallwall duedue to high impact velocity; thethe inertial effects deformationbehavior
These experimental results confirmed thepredictions predictionsofofprevious previouscomputer computer deformation experimental results confirmed the simulations of similar open-cell material behavior under impact loading conditions simulations of similar open-cell material behavior under impact loading conditions [20]

Summary

Introduction

Lightweight materials have unique physical and mechanical properties, such as low density and high specific stiffness, and are being increasingly used in modern industrial applications [1]. Metallic cellular materials are very suitable for use in impact-energy absorbers, which sustain deformations under high strain-rates [2,3]. This type of material has become a subject of investigation only in the past decade, and there are only a limited number of research results available regarding the strain-rate’s influences on the deformation mechanisms of metallic cellular materials. Mukai et al [6] comparatively studied the strain-rate effects on the polystyrene and closed-cell aluminum foam (ALPORAS) with the same relative density ρr.

Methods

Results

Conclusion