project F:Realisation-g
Design Realisation Relationships
Design Execution Prototype Validation Arduino development 1:1 Prototype
Final Model
Prototype view
Bench view
Prototype expoded
Electronic components
Prototype underconstruction
Prototype evalutation
Material and construction challenges
Cushion One of the challenges we faced was the stretch ability of the fabric for the cushion. The material that we planned on using at first was ETFE but after a meeting with Rienk de Vries at Buitink Technologies, we learned that it would take really a long time to change the amount of air in the cushions as the fragility of the material requires a small air input pressure. It also was not able to be inflated and deflated many times as it would lose it's characteristics of it's 30-40% stretchiness.
In order to still have a feeling of inflation and deflation of the ETFE, a pattern as illustrated in the project visuals could be made with 2 additional inner layers within the cushion. Yet as inflation and deflation (the experience of physical movement was more more important in the design) Rienk suggested semi-translucent stretchable fabric as an option but it would bevery challenging to weld together without a specific machine, plus it would require special valves to connect the tubing to the fabric which could hold the pressures building up inside. Apart from the fabrication limitations, the costs of about €16/m2 would be another hinder for us with the already big budget for the frames themselves.
In the end, the material of the cushion is a thick plastic sheet that we welded together using an iron into the needed shapes. Unfortunately, the school lost our order of air tubing and valves and we had to improvise a last minute solution for all the connections in and out of the cushions as well as to the valves with various diameters tubing ducktaped together for the final prototype.
The warped shape of the cushions in the end were a problem putting them into place as stretch folds were appearing where the cushions were not entirely parallel. In order to avoid this we folded the edges to shorten the cushions to get in line with the other side.
The prototype bench on which the stretch fabric has been put seems to work a lot better than the plastic cushions. Even though the fabric is only clamped inside the bench. The fabric stretches nicely and one can even sit on it. Proving the fabric has the interactive playful characteristics we were desiring for our building.
Structure The structure of the pavilion is a wooden laminated frame, however for the prototype we decided to construct a box-frame of several layers of 15mm MDF using screws, metal bars and bolts to keep it all together with laminated corners only. Due to the section of the structure built, the stability of the prototype became an issue. This was a problem specific to the prototype because in reality, the frame of the whole balances itself.
Electronic challenges
Apart from writing the code and getting the logic of the system to work and respond to all the imputs, one of the main challenges with the electrical system was finding the right resistors to change the 25V into 9V in order for the arduino not to burn out. One problem in the connection and hours can be spent in finding a problem that doesn't really exist. Also finding the right sensors to measure the air pressure or stretch of the fabric to not blow up our cushions has been a problem. This alters/complicates the code and delayed it for a bit.
Overall Challenges and Learning Moments
Group dynamics, in which 4 people have to work together to come up with a problem, concept, challenge, and various models, are always an interesting case where some sort of collaboration / mutual agreements / compromises need to be made. Our group can really take away lessons from our experiences here. Also with 3rd party collaborations, having to rely upon them is not always a good thing. The university signed for, and then lost an important large package that held all of our connection pieces and tubing for our model. A free re-sending of the package was promised, but unfortunately never happened. This has provided us with the necessary insights as to be on time ordering materials to include possible problems. This is of course only a viable option when there is plenty of time, not when on a tight schedule and the prototype design is still developing. This has shown that early preparation in detail is very important to be able to get an overview of the WHOLE. how many m1 or m2 of everything is required. To make a shopping list for every part of the design to be able to act quickly and respond quickly to possible problems.
A big challenge for us was to find places to order these special materials, especially because we did not need 50m1 of tubing, but only about 10m1. Also valves and connection pieces are by the dozen, which quickly cause rising costs. In a professional situation quality is first and a whole list of manufacturers are known. We had to figure everything out ourselves. This caused people in the group to be more secretaries then anything, especially because you never find what you're looking for straight away, and need follow up on calls made.
Yet the actual building of the thing designed is a great way of proving concept. An idea is nothing if it can't be built or doesn't work in practice. Like with any idea, when the details of how it is put together come to be during construction we ran into small things that we did not think of before or lacked the means to (also because of the lack of high quality materials, connections and the necessary machines to work with them) but also maybe because of a lack of experience with working with fabric. The double curved surface of the cushions caused for twisted sheets which caused right stretch lines in the fabric. When we blew it up for the first time this became visible, and we had to adjust the cushions to deal with it. Also the speed at which the cushions are inflated is less then expected. Directly with a pump, the cushions can be fully inflated in about a minute, yet with the sensors, valves and ducktaped pieces of tubing this has sadly increased by a lot. We knew that the compressors would generate a lot of noise, but in the building we could put them in a separate insulated room in order to only get the audible sissing sound of air rushing through the tubes and into the cushions. With the prototype however, the only thing that can be heard are 2 really loud compressors where being able to hear each other is unfortunately not possible anymore.
Also in this tight schedule we had to make some priorities. We wanted to have lights installed and have a clean finished prototype. In the end because of lack of time and adjustments having to be made the lights have been postponed and the finish is a bit rougher than envisioned. Yet the overall statement seems to work to our satisfaction, be it that the cushions respond a bit slower then we hoped for.
