In recent years, scientists have created shape-shifting materials that twist and bend when exposed to certain stimuli, such as moisture or heat. But these materials are usually made from polymers, so its uses are limited. Now, scientists from the Institute for Computational Design and Construction at the University of Stuttgart have figured out a way to bring these same properties to the oldest building material in the world: wood.
The shape-shifting technique is the product of three years of research. The team of researchers working on the project have created a 46-foot tall twisted tower made of wood to demonstrate their technique.
The tower is comprised of 12 wooden components, which were made by laminating two pieces of wood using different levels of moisture. The laminated pieces of wood were then dried out, which caused the material to curve naturally without the need for braces or molds.
The technique could be used to create bar furniture, living room tables and virtually any other piece of wooden furniture. It serves as an environmentally-friendly alternative to steel and glass - both of which are taxing on the planet.
Some designers, scientists and architects are calling it the "material of the future." This is due, in part, to rising demand and interest in cross-laminated timber. Cross-laminated timber is a building material that reinforces the weaknesses of individual wood pieces by laminating them together with another piece of timber.
Previously, architects would have to go to great, expensive lengths to get wood to curve. After applying moisture, they had to use costly and time-consuming molds and rigs. The equipment would hold the wood in place until it dried.
The new technique will be more economical and also allow for a wide range of variation in the types of curves produced, as no external force is required.
Using moisture to create curves or warp, wood isn't a new concept, but it's difficult to predict the outcome. Researchers used computer simulations to calculate the exact amount of moisture each piece needed as well as the direction of the grain of the wood to predict how the wood would curve. The more moisture, the greater the curve. In some cases, the researchers were able to create deep curves with a radius of about three feet.
After many experiments, researchers also learned that if the grains were perpendicular to each other, the final curved wooden piece would start to twist as well as the curve.
While challenges lie ahead, the new technique could lead to more environmentally-friendly, economical buildings in the future. The research team's tower is now on display at Germany's Remstal Garden Show.