I'm curious if there is something about acrylics which makes it impossible to make very large single pieces.
By the way, here's a big cool 3D printer that prints opaque acrylic: https://m.youtube.com/watch?v=b3CY3P28qyQ
I don't think any installation of this size can be truly safe. It has to be constructed in-situ being too large to transport so you would have to come up with some way of pressure testing the tank in-situ.
I know that metal fatigue is a known thing that airlines check for and when they went to carbon fiber they had to develop tools to detect fatigue/cracks.
There are other ways to scan for defects, but I'm mostly familiar with ultrasound phased arrays. Other NDT methods are also hard to use in the field after manufacturing.
[0] I work in NDT (non destructive testing), but I'm not a physics engineer and (work further up the stack from the actual probes/scanners). So this is an approximation, and I might be wrong.
[1] This random link is pretty useful to get an idea I think, but I'll also ask around our inhouse scientists if I get the occasion today!
https://www.olympus-ims.com/en/ndt-tutorials/transducers/pha...
So I'm going to put it in the "theoretically possible but nobody will do it" category for now. ;)
So you either detect it before commissioning or it will eventually fail if there is a flaw.
It forms the basis of some magic tricks involving walking on or supporting things in water. (I say some, the rest are totally magic and you should enjoy them.)
[0] https://www.atlasobscura.com/articles/stephen-hawking-time-t...
They could have steel bands providing reinforcement which would be just slightly obtrusive at some angles, but boy, now it would have bands and well, it's not an uninterrupted glass [acrylic] cylinder.
- 15 segments of acrylic glass
- 12 segments for the outer cylinder, 3 for the inner
- all segments worth 4 million EUR
- 200 wall thickness
- shipped in a steel construction
They did not say it, but from the video it looks like the segments were assembled in at the destination but not in their final location.
EDIT: I misunderstood, looks like the outer cylinder was assembled in-place, the inner one on-site and then lifted inside.
For completeness, here is the video, but it is in German:
Interesting bit:
> It got a little tricky when taping off the glass envelope with foil to prevent possible cracks. Acrylic glass is a sensitive material that absorbs water over time. If it then dries out too quickly, cracks can appear even in the glass walls, which are up to 20 centimeters thick.
All it takes is one incorrect application of a seam bond and a small crack will form. The crack may take decades to propagate with no way of detecting it. When the seam opens up a bit the crack will then propagate the entire length of the seam extremely rapidly and the whole tank will fail. Ideally failures would be slow and predictable but this is impossible with acrylic.
These sorts of failures have occurred before https://www.plasticstoday.com/materials/when-acrylic-aquariu... and will keep occurring as long as this type of construction is used.