Stable like a tree - durable notch structures

From nature ...

The branch forks of some trees can live for several hundred years without breaking.
When the wind shakes them, material stresses are created in the wood. These are particularly large in notches. The tree specifically reinforces critical areas there in order to distribute the stress evenly along the notch contour. Punctual overloading is avoided, and the branching is stabilized.

...to technology

To transfer the principle of optimized notches to technical components, biomimetics first examines where a load causes stress. Then, using biological growth rules, it simulates where material should be added (Computer Aided Optimization).

However, the simpler "method of tension triangles with subsequent smoothing" also leads to the desired success.

The optimized notch shape determined in this way is then transferred to the component. Thanks to this knowledge, orthopedic screws, for example, which stabilize broken bones, achieve a service life that is about twenty times longer. The method has also been used to improve components in vehicle construction.

Captions

Branch bifurcations withstand high loads without breaking.

On conventional notches (top), there are areas of high stress (red). In tree notches (below), the stress is more evenly distributed.

"Method of tension triangles"

Text of the information board in the Botanical Garden