A NUMERICAL METHOD OF MESOSCOPIC METALLIC FOAM UNDER HYPERVELOCITY IMPACT

Due to its lightweight and superior energy absorption characteristics, metallic foams are exceptionally appropriate for the debris shield of spacecraft. The mesoscopic structure of such a foam plays a pivotal role in enhancing its outstanding protective performance under hypervelocity impact. Numerical simulations permit us to explore the damage mechanism of its internal structure and the evolving characteristics of debris clouds. Leveraging the three-dimensional Voronoi tessellation in conjunction with the algorithm of background mesh mapping, this study constructed mesoscopic finite element models of the open-cell and closed-cell foam, duly considering the internal structure of randomness and alterations in ligament width. Subsequently, numerical simulations were executed employing the FE-SPH adaptive method within the LS-DYNA. The validation of the simulation was corroborated in comparation with disparate experimental cases. We found that different impact velocities lead to unique damage characteristics in the foam core. Based on the simulation result of a normal impact, we explored the damage mechanism of foam sandwich panels subjected to hypervelocity impacts. In accordance with the fragmentation process of the projectile and the evolution of debris clouds, it was found that the random internal structure of the foam engenders an irregular and skewed debris cloud, dispersing its energy and culminating in multiple concentrated particle clusters with a predilection towards a particular direction.