26 MOMENTUM • VIRGINIA TECH MECHANICAL ENGINEERING
A star in the world of ceramic engineering
Unexpected structural features found inside a starfish skeleton may help develop strong , lightweight ceramics .
Compared to metal and polymer-based materials , ceramics can better withstand high temperatures and corrosive environments , but their brittle nature often makes them susceptible to breakage . This behavior potentially causes problems for innovators trying to create lightweight porous versions of these materials , explaining why ceramic foams are not typically used as structural components .
Facing the challenging task of developing lightweight , high-strength ceramic materials , Mechanical Engineering Assistant Professor Ling Li has turned to an unexpected collaborator for design inspiration : the knobby starfish from the tropical Indo-Pacific . By investigating the complex and highly ordered mineralized skeletal system of this unusual marine species , Li and his research team discovered an unexpected combination of characteristics that may lead to developing an entirely new class of high-performance lightweight ceramic composites . Science Magazine featured their findings in a recent cover story .
Going light by going porous
Industries such as those in automobile and aerospace manufacturing have a strong interest in designing both strong and lightweight materials , combining the economy of better fuel efficiencies with strength . Industries find this balance difficult to strike , since stronger materials commonly possess high densities , and thus weigh more .
Nature , through millions of years of evolution , has come up with an ingenious way of solving this problem : using porous materials . The introduction of internal porosity potentially creates both extremely lightweight and mechanically efficient materials .
Several examples of porous materials exist in nature . These include the human skeletal system , the stems of plants , and the hives of honeybees . If one places these natural materials under a microscope , then one quickly discovers that they are filled with tiny voids or chambers . Natural growth forms these porous biological constructions very efficiently , and