Question: Have you ever made something that you tested over and over again and were certain it was correctly made but as soon as you used it it collapsed and fell apart?

George Fulton answered on 5 Mar 2019:

This is a great question!

I personally haven’t yet designed a material that is in service anywhere. I’ve only been working for 6 months!

Typically, if your experiment is well set up, then testing in the lab should be the same as in service or at least you’d take the differences into account. It is more likely that you forget to consider something.

For example, when materials science was only an emerging field, engineers didn’t realise that materials can fail at stresses much lower than the stress required to break the material apart. Weird right? This is called fatigue and it is as though the material is literally getting tired and eventually calls it a day and breaks. Fatigue is not well known but it is the main cause of aeroplane crashes for example. This is why fundamental materials research is so interesting and important, because unexpected behaviours/responses can be accounted for.

I’d like to add that for some materials for example, materials like glass, then testing the material over and over again might actually weaken it. So you could in theory test a window over and over and over and it to pass the tests, but then to fail when actually in service.