EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

The study investigates the crushing behaviour of the open-cell aluminium foam by means of experimental testing and numerical simulations. For this purpose, a wide range of quasi-static and dynamic compression experiments at different velocities were performed. Conventional Split Hopkinson Pressure Bar (SHPB) are limited by the maximal axial strain, defined by the length of the specimen and striker, bar material and the impact velocity. To overcome this limitation, a new so-called Direct Impact Hopkinson Bar (DIHB) test was implemented for dynamic testing. The open-cell sample's crushing behaviour was characterised by the single-side strain gauges measurements and high-speed camera observation. The dynamic experiments were conducted in loading velocity range from 14 m/s to 95 m/s, to account for all dynamic modes. Critical velocities were predicted with two constitutive crushing models and later validated by observing the deformation front formation at different rates. Micro-Computer Tomography (microCT) was implemented to capture the detailed morphology and topology of the samples, such as cell size, shape, and imperfections. Moreover, the sample's computational 3D models were generated from the microCT images and implemented in the numerical simulations (LS-DYNA). The results showed evident stress enhancement by the increase of the impact velocity. From that, the inertia effect, associated with the deformation front formation and propagation, was studied. Furthermore, a good agreement was achieved between numerical and experimental results, validating the novel experimental technique and the computational models.