This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: There are nearly 1 million pieces of debris larger than 1 centimeter (0.4 inch) in near-Earth orbit. As we continue launching spacecraft and telescopes to explore the universe, this debris poses a significant threat of high-speed impact damage.
In the Journal of Applied Physics researchers from Dalian University of Technology in China explored an eggshell-inspired design as a potential spacecraft protection material. "Natural biological structures have evolved to demonstrate excellent energy absorption performance over long-term adaptation," said author Yuxin Wang. It may seem counterintuitive to use eggshells as a blueprint for strength.
However, the researchers found that organizing water-filled aluminum eggshells into an array adds useful material properties when placed blunt-side down between two aluminum impact plates. Rather than being concentrated within a single eggshell, the energy from an impact gradually dissipates through the material, allowing each shell to sequentially collapse and deform. "A single eggshell breaks easily under local force, but the protection mechanism of the eggshell array is completely different," Wang said.
"The cooperative deformation of these eggshell units transforms the local impact load into distributed energy dissipation across the metastructure, thereby significantly enhancing the anti-impact performance of the target plates." Filling the eggs with water helps, too. Under high impact, the water sloshes around and suppresses the impact waves from propagating. This interaction between the water and the aluminum eggshell significantly reduces and dissipates the energy from the impact.
Several 3D prints and simulations were compared: aluminum plates alone, water-filled aluminum spheres sandwiched between aluminum plates, and the eggshell structures. The sandwiched, water-filled eggshell material performed best. It withstood high loads and reduced the velocity of an impact projectile by nearly 65%, compared with only a 51% reduction achieved by the aluminum plates on their own.
Among the various possible eggshell orientations, metastructure patterns with the eggs placed upright and their small end contacting the top plate were the most effective. Before being used for lightweight shielding on spacecraft, the material's geometry and filling need to be further optimized and impact-tested. The researchers are currently refining the thickness of the aluminum eggshells, their aspect ratio and their layout to improve the material's protective energy absorption.
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