To hunt, feed themselves or defend themselves, to cope with the vagaries of the environment, living species must make the best possible compromise between mobility, robustness, lightness and flexibility.

Evolution has also endowed them with the best anatomical principles to rationalize the consumption of energy and matter.

Their organization is therefore based on a design that must guarantee the best structural properties while ensuring material sobriety.

Nothing is left to chance. Nature has developed particularly intelligent strategies or materials and unlimited know-how to optimize the ratio between mass and robustness.

The architectures are meticulously crafted at every scale, from the millimeter down to the nanometer.

These adaptive composite materials and living structures often fulfill several functions simultaneously: lightness, thermal or acoustic resistance, elasticity, waterproofing, or even thermoregulation. In some species, remarkable resilience and self-repair abilities are even observed.

Remember La Fontaine's famous fable "The Oak and the Reed." Plant fiber, a true composite made up of rigid crystalline zones and flexible amorphous zones, is a naturally lightweight and incredibly flexible structure. It absorbs shocks without breaking.

In the design of a vehicle or an aircraft, for example, engineers have for years favored steel or aluminum. Biomimicry could allow for the exploration of effective alternatives.

In Slovakia, an inventor has created a composite bicycle frame made from a bidirectional fabric of bamboo fibers.

In addition to being lightweight, flexible, and strong, bamboo grows quickly and stores carbon, making it a high-quality renewable material. After numerous tests, the verdict is clear: the bamboo frame absorbs shocks better than a traditional steel frame, and without breaking.

The structure of bamboo could well revolutionize the structures of many components in different industries, starting with those of mobility.

One of the greatest feats imagined by nature, one that has made entire generations of inventors dream, is the flight of birds.

To be able to fly, sometimes over long distances, birds must have particularly lightweight anatomies to minimize effort and energy expenditure. Their bone structure is therefore of obvious interest to analyze.

Let's travel to the Amazon rainforest: the toucan is a remarkable and colorful bird. It is especially its beak that impresses with its size. It measures almost a third of the animal's length.

Despite its imposing size, it represents only one-twentieth of the toucan's total mass: practical for flying . At the same time, it must be strong enough to allow the bird to defend itself and hunt.

The compromise between lightness and strength is achieved through a sandwich structure. The internal structure is spongy, lightweight, and composed of closed-cell foam. It allows for shock absorption and dissipation.

This inner part is surrounded by solid, dense outer membranes made of overlapping hexagonal keratin plates bonded together with organic glue. This enhances the overall robustness of the beak.

On a smaller scale, natural materials, such as those found in insects, crustaceans, and shells, have already enabled researchers to create new materials that are both lightweight and strong. Here are a few particularly surprising examples.

Arthropods form a group of animals characterized by their segmented bodies. They include insects and crustaceans with a shell, an exoskeleton, called a cuticle.

This tissue is very resistant and represents a line of defense for the animal. It absorbs shocks that may occur to protect the internal organism.

Its robustness is due to an alternation of flexible and rigid layers. A team from the Wyss Institute at Harvard University in the United States has succeeded in reproducing these micro-structural and multi-layered properties to develop a material as hard and tough as aluminum, but twice as light.

This bio-plastic has been named "Shrilk". Composed of chitin, a flexible and resistant natural material, and fibroin silk proteins created by many insects, Shrilk is a natural, biocompatible and biodegradable compound.

Image credits: ©Wyss Institute at Harvard University

In the automotive industry, for example, aluminum is gradually replacing steel because it is lighter. In just over fifty years, its quantity has increased from 38 kg to over 180 kg on average per car. This trend is expected to continue, reaching 250 kg by 2028.

Thanks to its mechanical properties comparable to those of aluminum, its superior lightness, and its recyclability, Shrilk is a promising alternative that could eventually replace it! It could be used on a large scale in numerous industries. Renewable and mass-produced, it is perfectly compatible with additive manufacturing.

In many industries, components are subjected to high temperatures. A significant technical challenge.

Because at high temperatures, the mechanical properties of metals degrade , rendering them unusable.

The most commonly used materials today to overcome this problem are ceramics , known for their very high resistance to high temperatures. Unfortunately, they are also very fragile, particularly in the face of crack propagation.

The world of biomimicry has a deep understanding of this: it is a problem often encountered in living things that offers us a powerful source of inspiration.

Abalone are marine molluscs with a shell. Their natural mother-of-pearl has a truly remarkable multi-layered microstructure.

Several French laboratories joined forces to study it. Thanks to this biological model, they succeeded in creating a genuine artificial mother-of-pearl ten times more durable than traditional ceramics. This new ceramic could allow for a reduction in size and therefore mass of various ceramic pieces.

Image credits: © Sylvain Deville, Florian Bouville, LSFC

Biomimicry can go even further. Because in addition to being useful as a model for the creation of new materials, nature can inspire design algorithms.

Researchers and engineers have sought to create new structures that are stronger, more resource-efficient, and lighter, as well as innovative design methods inspired by living organisms. Here is a relevant example.

A new 3D design algorithm was created by Autodesk and APWorks to design internal partitions for the Airbus A320. These partitions, which separate the different sections of the cabin and support the crew seats, are 65% lighter than existing structures. This software draws on the principles of bone growth, in which the regions most subjected to mechanical stress are the most dense and robust. The design algorithm tests a multitude of distinct structural configurations to select the most resource-efficient one, while still meeting the established constraints. The structure is thus optimized at both the macro and micro levels.

Such an algorithm makes it possible to minimize the mass and materials of a structure while maintaining strength and robustness. Applied to structural design, its potential is immense, and this is true across various industries.

Image credits: ©The Living