Environment

MIT system assigns unwanted tree forks to use in load-bearing structures

MIT system assigns unwanted tr...
Some of the tree forks used in the study
Some of the tree forks used in the study
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Some of the tree forks used in the study
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Some of the tree forks used in the study
One of the forks is robotically guided through the cutting process
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One of the forks is robotically guided through the cutting process
The team's proof-of-concept sculpture, which will eventually incorporate more of the nodes
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The team's proof-of-concept sculpture, which will eventually incorporate more of the nodes
The waste wood from the donor trees, prior to the selection process
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The waste wood from the donor trees, prior to the selection process
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Wood is becoming an increasingly popular building material, but the timber is harvested mainly just from the long, straight trunks of trees. Aiming to reduce waste, an MIT team has developed a method of also using a tree's load-bearing junctions.

Led by Assoc. Prof. Caitlin Mueller, the researchers started by collecting sections of waste wood from a group of trees that had already been cut down in the city of Somerville, Massachusetts. The scientists were specifically interested in the Y-shaped forks where the trunk or a large branch divides in two. Ordinarily, such parts are just chipped into mulch or burned.

"Tree forks are naturally engineered structural connections that work as cantilevers in trees, which means that they have the potential to transfer force very efficiently thanks to their internal fiber structure," said Mueller. "If you take a tree fork and slice it down the middle, you see an unbelievable network of fibers that are intertwining to create these often three-dimensional load transfer points in a tree. We’re starting to do the same thing using 3D printing, but we’re nowhere near what nature does."

One of the forks is robotically guided through the cutting process
One of the forks is robotically guided through the cutting process

Once the scientists had a good collection of forks, they proceed to 3D-scan each one, then add its digital model to a database. Utilizing what's known as a Hungarian algorithm, it was subsequently possible to determine which forks within that database would best meet the load-bearing requirements of a specific Y-shaped node – where two straight pieces of material come together to support a load – in a particular human-made structure.

The system could also work in reverse, showing how other aspects of a structure should be altered in order to utilize a given tree fork for a specific node.

In the next step of the process, another algorithm was used to guide the robotic cutting of the selected forks, so they were able to best fit into and bear the load of their respective node locations. Finally, a computer model guided the team through the assembly process, showing which forks were intended for which nodes.

The team's proof-of-concept sculpture, which will eventually incorporate more of the nodes
The team's proof-of-concept sculpture, which will eventually incorporate more of the nodes

Although it may be some time before we see an actual building constructed using the technology, Mueller and colleagues did build a proof-of-concept wooden sculpture which was displayed on the MIT campus. Because they were delayed by the pandemic, the piece is still a work in progress – it presently incorporates 12 tree-fork nodes, but should ultimately include approximately 40. It will then be installed in Somerville, at the site where the donor trees once grew.

Source: MIT

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13 comments
13 comments
ClauS
What researchers recurringly fail to understand is that there are billions of people in the world. In order for a product / concept to be usable it needs to be easily scalable. Here you need to select the fork, scan it, hope that you have something in selection suitable for the needs, or change the design to suit the available forks. This can go only so far, maybe suitable for some boutique products but not for the rest of us.
Bob Stuart
Now if they can only discover an efficient butt-joint in fibrous material, they'll have something more than a decoration.
Catweazle
Concerning the use of straight timber, before the Dissolution of the Monasteries by Henry VIII the construction work in the area where I live was regulated by the monks from Fountains Abbey.
All structural timber had to be cloven, anyone found using sawn timber in a load bearing structural application was flogged and made to burn the aforesaid timber.
The A-frame roof truss in my three foot thick stone walled cottage is from that period and was recycled around four hundred years ago, the roof battens are recycled Napoleonic War ships timbers, a couple of years ago those on the windward side of the house came to the end of their lives and had to be replaced, the rest will be good for another century or two yet.
michael_dowling
The smaller ones could be made into slingshots-nothing wasted!
vince
They make great sling shots.
Jerome Morley Larson Sr eAIA
these were prized for the old wood sailing ships = plus ca change; plus ca la meme chose.
1stClassOPP
If the forks (crotches?) were left a little more extended, could they serve as springs for certain applications?
ljaques
The MIT guys should read The Wheelwright's Shop, written by George Sturt in 1923. He covered a lot of the interconnected grains of different wood species which work best for building the wheels on heavy duty horse/ox-drawn wagons and carts.
Matthew Harrison
Sounds similar to this work in the UK in 2016. They also used robotic milling to create joints http://hookepark.aaschool.ac.uk/woodchip-barn/
TechGazer
The title made me picture next year's cars using these chunk of wood at various places. At least it gave me a good laugh.

Since they have to use structural plates to attach these forks, I fail to see what they're gaining, at a serious cost in logistics (collecting, machining, distributing, etc). Oh, right, they've also left out seasoning. Drying those forks without splitting isn't easy.
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