Halloween Themed Tensegrity Structure

Images:

Summary Section:

The function of our project was to demonstrate tensegrity in action with our plate designs and beams having tension and compression elements to create tensegrity. Our model was made to fit in a 20x20x20 constraint box. It was created with my partner, bumblebee, using the theme of Halloween with ghosts as the base design and other spooky-themed words and designs on all sides to make the project look more fun.

Lesson Plan/ Activity:

With a partner, you will design and create a single custom Tensegrity Structure of equal complexity or greater as the tables depicted above (as determined and approved by the instructor).

Part list:

Assembly/ Construction Instructions Section: 

1. Once printed, you should have four pieces that look roughly like this:

  If there are extra stringy pieces of filament, cut them off with cutters or just with your fingers.

2. The original pieces will not fit in the holes. Use cutters and sandpaper to round off and narrow down along the edges of the pegs on the triangles. Use the same tools to round off the corners and remove excess filament to widen the holes in the ghost. Be sure to check the fit repeatedly to ensure that everything fits properly and the fit isn’t too loose. 

Pieces After:

3. Once the pieces are whittled down, wiggle and shove them together, don’t be afraid to add extra force! 

4. Next, identify the small, slightly darkened circles in all part pieces. There should be five in total, four on the plate and one on the beam. This is where the screws will be inserted.

5. Use the smallest available punch and knock gently with a hammer until a hole is formed at each marking. Take it slow to avoid splitting. If the width of the hole is small, use a small screwdriver to widen it. Use this technique for the baseplates and the triangles, but be extra careful with the triangles. They may be more prone to breaking.

6. Insert hooks in each hole, screwing them in carefully.

7. Tie a simple knot to the face that will be the top of the structure using pliers to pull it tight. Do this to all of the screws on both the plates and triangles.

8. Have one person carefully hold the top face up with a level to ensure that it is evenly distributed and tie the strings to the bottom face using pliers once more.

TIP: The length of the initial cut strings doesn’t matter, but it helps to use a string much longer than the actual measurements. Tie the base string first at 0.5 cm, and the others should measure out to be 16cm.

9. Cut any extra strings off and tighten them so all four sides are level!

10. And that’s it! Now you have a fully functional tensegrity ghost structure. 

Design Choices: 

We started the process of brainstorming ideas and themes that we could start our sketches with using google drawings. We created 4 different ideas to later decide which would most likely work the best functionality-wise and design-wise. We went with our ghost-themed design. 

After our basic sketch, we then drew one adding in measurements that would keep the whole assembly within our 20x20x20 constraint box we were given with the plates staying in our created constraint box of 12x15. 
 

Using the sketch with measurements, we then moved to solid works to start creating each piece. We continued with the ghost base shape, but the beams were made into more solid triangles for stability because there was potential that the thin-shaped pieces we sketched wouldn't hold up our assembly. A few small measurements were also changed to make the design work better in Solidworks for both the plate and the beam. Once those were built we started our assembly, but we added two new designs on both beams to make the assembly more aesthetically pleasing leaving no empty faces. The new designs weren't a part of our original sketch but kept with our theme of Halloween while being able to fit within the space that was left. One functionality change was made regarding the assembly where we changed the width of our plates and beams to assemble everything more easily as it gave us more room to insert the hooks. The previous measurements may have been too thin to create a stable shape once everything was printed, so we enlarged it to make sure there were no issues we would find during future assemblies.

For our final printed parts we changed the structure of our beams as we found that during assembly of the rough draft of the structure, our design wasn't made with the right center weight distribution to hold the pieces up using only the fishing line as a connector. 

Once all fishing lines had gotten tied connecting the plates, the middle line was never able to hold up our structure even when we changed the length of the connection multiple times to see if the difference would change anything regarding the stability. The length of the fishing lines connecting the plates was also changed multiple times to achieve a leveled structure, but we could never reach the point of the plates staying up when we weren't holding them together. The tension connecting the beams will be achieved by a point on the beams being curled into each other for our final printed parts so more weight is able to be held. We are choosing to add a curled, hook-like shape coming from the point where our hooks were placed on the beam for version 1 so no major changes have to be made to our design and the drawing on the sides of our beams. The issue we kept finding was that no weight was able to be held with the placement of our hooks on our triangles that were at a ninety-degree angle of the plates which gave no strength to the structure. We will make a few changes to our parts that are for more aesthetic purposes than functionality. The engravings of the ghosts' faces will be engraved deeper than what we chose for our rough draft structure so the design can be seen more clearly. The stripe design on one side of our beams will be changed to only 3 stripes so it will also print out cleaner than what it came out as at first. Once we change the shape of the beams to achieve an even weight distribution, there should be enough tension created to support every part. After finishing the build of version 1, holes were added into our solidworks design for where the hooks would go into the plates and beams to ensure the hooks would be in the same place on all pieces.