We continued with experimentation on our catenary chains through this third week. The chain link we used for these new experiments is even thinner than the last ones used. We wanted to make sure that with our method of hardening the chain to flip it around would work that is why we went with the thinner chain, thinking that it would hold better. Also, we wanted to create more complex shapes so we started developing a mesh or net type of structure. We choose on to this particular structure looking into that the structural capacity so it could hold better once it was hardened with glue. With this model we noticed that we could arrange the structure in different configurations thanks to the peg board, some images that show this.
The next model we would create was also going to be a more complex structure, but also had to be structurally sound given that we wanted it to hold with the glue applied . So we made the decision of going with a structure that had a strong element in the middle and that it branched out according to our categorization this shape is our basic array then continuing on to a more complex. The connection between the catenaries had also to be applied to contribute to the structure strength. See images
Hold your Chain!
After a few attempts, our hardening process consisted on applying large amounts of glue directly on to the chain. The glue that we were using was a particular type of tacky glue that usually does very well to hold wood models. The glue had to be flexible enough and also not so fast to dry up, so this one was excellent for the use we wanted. This was most successful but it also had to be standing for at least two days for the glue to completely harden the chain up.
We also gave ourselves to the task of diagramming the models as best as possible with a proper 3d representation, we did this with the help of Rhino 5.0 software. However the curves represented on the program are not exact catenaries, the tool allowed us to recreate as best as possible the shapes, but the force that you apply on the curve tool is still not generated by the pull that gravity excels on real live.
The diagramming was concerned with showing the behavior of the chain, the distance between them, and the connection points between them. Looking at this derivatives, then we were able to categorize them on to different types. This 3d diagrams are very good at showing all this features in a 3 form drawing format that we arrange.
One of thhe main problems we found between the diagram and the real model is that gravity pulls uniformly through the whole chain that also has a uniform density. In the case of the model, you could only apply certain pull points that would give you the desired curve. That difference is definitively represented on the diagrams and pictures difference.
Our presentation consisted in a 24” x 60” print board that showed the diagramming previously explained and some of the pictures of the models that better clarified the categorization process. We also presented the models that were able to hold better with the glue applied. Although the models did not hold for much time with out bending or altering its form; they were able to hold for some minutes; enough to at least to show to our distinguished visiting critic, Andrew Kudless through a Skype session. Andrew acknowledged and praised our effort to categorized and diagram our models. He also noted that the diagrams did not show a true depiction of the catenaries, specially in the linked categories, given that the catenary shapes gets affected and somewhat deformed when we have a linked chain attached. Andrew was very happy with our effort, he seemed very happy with the models shown and did recommend us to keep up building on to the experimentation models to come up with more altered shapes and sizes.
We will follow through the recommendations made by Andrew and by our professor Kevin. Also, we believe that as we continue further with our studies going into 3d modeling with rhino and grasshopper, we believe we have gained important insight into the process that goes into forming this shapes, and how gravity affects them. We are sure that this is going to be helpful as we get more into grasshopper.