Reaching out

by Marisa Morby

Photo by Museum of New Zealand Te Papa Tongarewa on Unsplash

Trees bend in the wind, their branches contorting over time, bowing, twisting, reaching, but not breaking. Throughout hundreds of years they withstand these elements, growing stronger, if not taller. How do they do this? How does this trunk stay strong, not cracking or breaking despite this pressure? This comes down to an evolutionary building block that plants employe. And now designers are mirroring this to create beautiful sculptured pieces, and construct buildings with structural integrity and an organic beauty inspired by nature.

In material design the concept is called Evolutionary Structural Optimization (ESO). In nature though, it’s simply the way trees and bones grow to evenly distribute stress and provide the ability to stabilize themselves under pressure.

*“Trees and bones achieve an even distribution of mechanical tension through the efficient use of material and adaptive structural design, optimizing strength, resilience, and material for a wide variety of load conditions. At the scale of the cell, trees arrange fibers in the direction of the flow of force, or principal stress trajectories, to minimize shear stress” *

- “Structure Distributes Stress” from AskNature.org

That beautifully curved tree trunk on a windswept coast is the result of this principle. As the wind continually pushes the tree, it of course starts to bend, but it’s also able to add extra wood to its trunk where force is the greatest, keeping it strong against the wind, and reducing the possibility that it will snap.

Material designers are taking this principle one step further. If trees and bones are adding material to these stress trajectories, what would happen if you take away material where there isn’t as much stress? This results in a piece that uses less material, is light weight, and very strong and durable.

[object Object],[object Object],[object Object] — A table by designer Joris Laarman, using the evolutionary structural optimization concept to remove materials where it’s not necessary. Photo from Material Strategies: Soft Kill Option.

Car makers have been using this technique for years to create cars that perform better under crash conditions and parts that are lighter weight but still sturdy.

Similarly, engineers are taking direction from bone growth to organically improve structures. Bone is somewhat unique in that the more stress it’s under the thicker they become. This is why exercises like weight training can be so effective in combatting osteoporosis. As you put your bones under stress to lift heavier weight, the bones adapt and become more dense.

The material these engineers are working on is “a sponge-like structure containing a liquid mineral solution that enables self-repair and reinforcement over time; so when LIPPS experiences repeated mechanical loading, material becomes stiffer and better at absorbing energy.” It basically mimics bone in that the more stress it’s put under, the stronger it becomes. The team is hoping to use this for medical devices, robotics, and vehicle parts.

That these sweeping trees and the ever-adaptable nature of our bones inspired designers and engineers is a testament to the impact of nature. Someone saw these trees and thought, “how do they still stand?” Someone learned about how our body works and thought “why do our bones improve under stress?” There is beauty in these windswept trees and in the strength our bodies lend to us. It’s inspiring to see others take that beauty and strength and apply it to so many areas: art and design, functional design, and scientific exploration.

Photo by Peter Law on Unsplash

Want to learn more?

Some of the references I used for this week’s newsletter.