Blaine Brownell, AIA, is a regularly featured columnist whose stories appear on this website each week. His views and conclusions are not necessarily those of ARCHITECT magazine nor of the American Institute of Architects.
The search for natural wisdom often leads to surprising places. A team of scientists from the RWTH Aachen University Foundry Institute and University of Freiburg Plant Biomechanics Group sought to develop a more robust aluminum composite structure. For a model precedent, they turned to a pomelo fruit peel. The world's largest citrus fruit with a taste similar to grapefruit, the pomelo has a hierarchically-layered peel comprised of fiber-reinforced foam. This tough outer surface allows the 1-2 kg fruit to survive intact after 10 meter drops—a capacity that attracted the researchers' attention.
The scientists translated the microstructure of the pomelo skin into a metal composite with a robust alloy of aluminum-silicon on the outside and a pliable aluminum core. The resulting hybrid outperforms either of its parts, with a greater ductility than the aluminum-silicon alloy and a higher tensile strength than pure aluminum. Based on the experiment's success, the researchers aim to develop high-performance automotive components and other applications benefiting from lightweight and resilient materials.