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Tl;dr stress concentrations such as scratches and gouges can lead to sudden failures in acrylic structures under pressure.

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That was, for me, the least interesting of the failure modes mentioned, the most alarming being:

> The phenomenon behind this is called creep rupture—the disentanglement of the molecules of plastic over time, at a stress level significantly below the yield strength—yes, below the yield strength—of the plastic.

Also known as crack propagation, but yes interesting to see in non metals.

It is standard for high pressure equipment and welds to get xray tested. Should be the same for these structures too especially as they age.

What would be the method and tooling involved to xray such large and unique structures? Is there a US company specialising in the service or who typically does it?

Here's an example :

https://www.mistrasgroup.com/how-we-help/field-inspections/a...

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