Architected materials alter the structure of materials to achieve properties that cannot be obtained using the material itself. They allow us to improve on the design of materials in their natural state to create new and innovative designs. Architected materials also enhance sustainability and help achieve multiple functions in the same component.
We tend to think of materials as the stuff that makes up the world around us - materials like steel, rubber, and ceramic. We then shape these materials into products and objects we can actually use, like bridges, tires and dinner plates. And the reason we choose a particular material for a particular product is that the material in question has some properties that the product needs - bridges need to be strong enough to resist the load of passing traffic - steel is a strong material for this purpose. Tires need to absorb energy and provide grip - rubber has the necessary compliance to do this. Dinner plates need to look good after repeated use - ceramics are hard and resist scratches. Over the past several decades, hundreds of new materials have been developed with improved properties for these kinds of applications.
But did you know that there is a way to make a material that is not just about the material itself? It involves designing the material in such a way that it acquires different properties on account of not only its basic composition, but also its design. We see this principle in nature a lot - the same materials used in different ways as evolution has led adaptations by different organisms in new directions…beeswax to make honeycomb, soil and saliva to make termite structures, the dermal scales of shark-skin.
In engineering, we call them architected materials - because we now are architecting the structure of these materials towards achieving certain properties that cannot be obtained using the material itself. Because doing this often gives the material a new behavior that it didn’t have in its intrinsic state, we also refer to these materials as meta-materials. In a way, we transcend the limitations of the material by exploiting design.
The convergence of two technologies, 3D printing and Computer Aided Design, or CAD, has boosted the interest in architected materials. Prior to the advent of 3D printing, we were limited to fabricating honeycombs and foams - the kind you find in packaging materials used in shipping goods across the world. But with 3D printing, we can now create complex geometries at small enough sizes where we can influence the behavior of a much larger structure. The question then is, how do we design these materials? Enter CAD. With modern CAD tools it is possible to fill in a 3-dimensional volume with a wide variety of architected materials.
Architected materials are broadly speaking either honeycomb like, 2-dimensional designs that are extruded in the 3rd direction, or true 3-dimensional structures made of beams or surfaces. Beam-based architected materials are typically called beam-lattices. Surface-based architected materials are normally derived from mathematical functions and take a wide range of forms such as the gyroid and Schwarz-P shapes.
Why should we care about architected materials? There are several reasons: firstly, they have the potential for reducing the amount of material we need for a given product - so they can enhance sustainability. Secondly, by manipulating design at smaller scales, we can achieve multiple functions in the same component - consider the bones in our bodies. They provide structural stiffness and strength, protection to our internal organs, and absorb energy, all while serving as storage sites for important minerals and having the lowest mass possible. A key reason bone is able to do all of this lies in how it exploits architecture and how that varies across the body.
The architecture in nature is, frankly, very impressive.