Curved structures made out of wood are what architects dream about. But doing that requires a ton of energy and results in a lot of waste.
But researchers at the Laboratory for Cellulose & Wood Materials, the Institute for Building Materials, ETH Zurich and the University of Stuttgart found modeling the wood while it is in a drying phase can create these curved structured. The team published their work in the journal Science Advances.
Machines required to make curved wood today
As it stands, using wood to make curved structures required machines that have to cut out the parts of the wood to make it curve. To overcome that the team of reseachers utilized wood's ability to absorb and release moisture to shape the material. When wood gets mositure in it, it leads the material to warp. In manufacturing, that's long been a challenge but the researchers used it to their advantage.
The team first set out to see if they can predict when wood warps using computer simulations that took into account factors such as the wood type and how much moisture was absorbed. Armed with that knowledge they created computer models to determine if they could get the wood to bend in certain ways using wet and dry techniques. Based on the models, the researchers concluded it is possible to create curved structures out of wood without the need for machines that hurt the environment.
Researchers created a 14-meter structured with their technique
As a result of their work, the researchers were able to use wet European beach and Norway spruce wood to create a structure that is now in Germany. The planks of wood were glued together and as they dried one layer shrunk in size while the other didn't, resulting in the bending of the wood. The wood was then combined with other planks that were bent in predetermined ways so that they could construct the 14-meter structure they call the Urbach Tower.
The Urbach Tower is the first time the researchers' process has been used to construct an entire building.
"The growing timber manufacturing industry faces challenges due to increasing geometric complexity of architectural designs. Complex and structurally efficient curved geometries are nowadays easily designed but still involve intensive manufacturing and excessive machining," wrote the researchers. "Using time- and moisture-dependent mechanical simulations, we demonstrate the contributions of different wood-specific deformation mechanisms on the self-shaping of large-scale elements."