A team of international researchers turned to mother nature with the aim of 3D printing ceramic composite materials with bio-inspired curing characteristics.
Ceramic composites with damage resistant properties are in high demand, as toughness is a key requirement in a wide variety of industrial applications. These materials also tend to offer combinations of chemical and mechanical stability, qualifying them for use in everything from automotive and aerospace to energy systems.
Unfortunately, many of today’s conventional ceramic composite processing techniques, such as ice modeling or gel casting, are unable to create parts with complex, custom geometries, due to manufacturing limitations. of mussels.
The international team is currently investigating how the protective structures found in mantis shrimp can be used in conjunction with digital light processing (DLP) 3D printing to create geometrically complex ceramic composite components.
What’s so special about the Mantis Shrimp?
Mantis shrimp, also known as stomatopods, are a type of small, multicolored marine crustacean. They are well known for their aggressive nature and their characteristic fist-like appendage called a dactyl club.
The built-in weapon is used to crush and kill hard-shelled prey such as crabs and snails, moving with incredible force to pierce even the most protective shells. In fact, dactyl clubs are believed to be able to achieve accelerations of up to 10,000g, resulting in impacts matching the speed of a .22 caliber bullet.
But what makes them so durable? Dactyl clubs feature a bi-continuous structure that helps them absorb impact and filter out damaging shear waves without breaking a sweat. The organic phase is made up of chitin, a compound commonly found in the shells of insects and crustaceans, while the inorganic phase is made up of amorphous calcium phosphate and calcium carbonate.
Together, the dual problem structure forms a crack-resistant protective effect that protects the club, much to the dismay of the Mantis Shrimp’s prey.
116x hardness improvements
In the present study, the research team paid homage to the work of natural selection and 3D printed complex ceramic composite structures with bi-continuous zirconia/epoxy phases.
To test the strength of the biomimetic printed structures, they applied the concept to restorative dentistry, 3D printing a series of pontine bridges at 75% vol. zirconia. The graduated ceramic walls of the bridges increased linearly in thickness from 0.3mm to 0.7mm, showcasing graduated stress distributions that dispersed all compressive stresses across the parts evenly.
In a series of compression tests, the team found that their printed ceramic composites increased in strength by up to 213% compared to pure ceramic. Young’s modulus increased only slightly in the printed pieces. Amazingly, the hardness of the printed structures was also increased 116 times, while allowing for unique geometries that would have been impossible to manufacture with conventional techniques.
Ultimately, the study holds great promise when it comes to biomimicking the bi-continuous architecture of mantis shrimp. The 3D-printed ceramic composites exhibited excellent toughness and compressive strength characteristics, which are especially useful in custom dental restorative applications.
Further details of the study can be found in the article titled “3D Printing of Ceramic Composite with Biomimetic Reinforcement Design”.
This is certainly not the first additive manufacturing research centered on biomimicry. Just recently, a team of American researchers used 3D printing technology to create adhesive suction cups inspired by the octopus. The team, led by Virginia Tech, developed its own nature-inspired nervous system that can detect objects and automatically activate grip in milliseconds. The adhesive skin has been integrated into a wearable glove, providing a new way to manipulate objects in an underwater environment.
Elsewhere, researchers at ETH Zurich have 3D printed artificially colored nanostructures, taking inspiration from the wings of a butterfly. Native to tropical Africa, the wings of the Cynandra opis species are characterized by their bright colors. Rather than being pigment-based, these colors are structural, meaning they are produced by complex nanostructures on the surface of the wings.
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The featured image shows the mantis shrimp. Photo via Roy L. Caldwell, University of California, Berkeley.