VELLUM FURNITURE COMPETITION
THE FLOW OF SITTING
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Movement varies in both growth and scale. In order to create an environment suitable to movement one must understand how people move and why, or the flow of human movement. In this study, the Flow of Sitting attempts to encourage movement in solid wood through kerfs, or cuts meant to purposefully weaken the integrity of the wood, just enough to bend under stress without breaking. Like a crowd pushing through narrow walkways, pressure builds, but is accounted for in an adjacent space encouraging movement. The organization and structure of these kerfs creates its own kind of dynamic rhythm as a result of accounting for stress. As such the pattern varies to account for where people move the most; cuts are further apart in the seat to account for a larger load while they are closer together in the backrest to promote a wider range of motion in the upper torso to shoulders. Moments of tensions are located where the user applies pressure. The form of the seat and backrest are then meant to be formed by the body.
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MATERIALS + TECHNIQUE
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For this experiment I tested a number of cutting techniques and woods before settling on this combination. I found that I wanted to cut perpendicular to the grain to allow enough range of movement without too much pressure, and in contrast the wood was more likely to splinter or snap when cutting parallel to the grain. Likewise cutting perpendicular to the core of the wood allowed for the least amount of flexibility, but was too rigid. Cutting perpendicular to the core of the wood was also not ideal as it meant buying wood in long lengths, which was not always available.
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The width and depth of the cut also created parameters for the range of motion that the wood could withstand. For this experiment I used 1/8” wide table saw for the cuts. Depending on the flexibility of the wood a thinner blade or CNC would have been more ideal in order to create more control and support in the motion of the wood. In contrast to my precedent, Carolien Laro’s “Spring Wood”, whenever I overlapped cuts the wood had a tendency to break towards the adjacent cut. With my weight of 140 lb. I could sit on cuts as deep as 7/8” deep on both sides of a 2” piece of wood with great flexibility, however someone with a weight of 150 lbs. would break this, thus I ended up settling at ¾” deep cut on both ends of a 2” piece of wood which allows anyone up to about 200 lbs. to sit on it though it is not as flexible to those who weigh less.
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In addressing the material, I took precedent again, from Carolien Laro’s “Spring Wood” stool which also flexes using kerf patterns. In her project she uses Ash wood. I tested Doug Fir, plywood, and ultimately settled on Ash as well. During this testing I found that with an elastic modulus of 1,765,000 lbf/in2, Doug Fir snapped too easily. Plywood with minimal cuts and basswood were too flexible. Ash wood has an elastic modulus of 1,360,000 lbf/in2, and thus Ash wood does not snap as easily and is more flexible than Doug Fir, but less flexible then plywood and basswood.
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FRAME
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In order to support this flexible seat and back, a rigid frame was necessary, however the joints ultimately had to allow for motion. To create this twisting motion I went with 3/8” round solid steel rod that I would bend, weld, and cut so that the wood could sit and rotate on at least one axis of motion. This axis of motion becomes a part of the design following the kerf cuts along the wood. This round rod is present throughout the project to create a cohesive and supportive design.