A team at the National Institute of Standards and Technology (NIST) has developed a tool to monitor changes in widely used composite materials known as fiber reinforced polymers (FRPs), which can be found in everything from aerospace and infrastructure to wind turbines. The new tool, integrated into these materials, can help measure the damage that occurs as they age.
[...] Since the 1960s, scientists have been experimenting with ways to make FRPs lighter and stronger. This has often meant testing the bond between fiber and resin. As reported in a previous publication, the NIST team added small molecules that fluoresce after the impact of mechanical force. These molecules, called "mechanophores," change color or light up, helping identify tiny nanometer-sized openings or cracks between the fiber and resin.
The NIST team has taken this technology to the next level by incorporating the mechanophore throughout the composite resin. Although not noticeable to the naked eye, the newest approach allows scientists to use special microscopy imaging techniques to measure FRP damage. The approach incorporates a minute amount (less than 0.1% mass) of a fluorescent dye called rhodamine that causes no appreciable changes in the material's physical properties.
If the new mechanophore is embedded in structures made of FRP, field testing for fatigue could be done inexpensively and on a regular basis. Structures like wind turbines could frequently be scanned easily for interior cracks, even years after they've been erected.
Journal Reference:
Jeremiah W. Woodcock et al. Damage sensing using a mechanophore crosslinked epoxy resin in single-fiber composites, Composites Science and Technology (2020). DOI: 10.1016/j.compscitech.2020.108074
(Score: 2) by HiThere on Thursday February 20 2020, @04:39PM (3 children)
It seems to me that adding something to the composite would be likely to weaken it. Perhaps it would produce lots of small sites of developing weakness.
That's just off the top of my head, though. I suppose with careful design it could be neutral, or even strengthen the material. But it seems unlikely. (OTOH, I'm not a materials scientist.)
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(Score: 2) by EvilSS on Thursday February 20 2020, @06:39PM (2 children)
(Score: 2) by HiThere on Thursday February 20 2020, @08:33PM (1 child)
You're getting something out of the summary that I am not. And I don't think it's there, after rereading twice. (Also, a reference to a prior article doesn't count as a reference to this technique.) So checking the article itself I didn't learn anything substantially new that wasn't in the summary.
They don't seem to have examined what adding their custom particles does to the strength of the composite over time. Of course, the article itself was not the technical report, and they may have addressed that issue there, but I'm probably not competent to evaluate it.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 3, Informative) by EvilSS on Thursday February 20 2020, @09:22PM