Special Paint which can show stress distribution, HELP!!

[kamenko]

I have heard that there is some special paint which is used on the way that some part is painted (e.g. beam) and then loaded by force. WHat happen is that paint change it color and that color spectrum can be compared to some kind of stress comparison chart to evaluate results.
Does anybody know something like this ?

 

[brad]

The concept of a strain-paint which physically changes color is something of which I am not aware. There are other methods of strain-measurement which are similar:

There are two concepts which you may be confusing--there is the concept of photoelasticity, which shows strain distributions in a part comprised of particular materials when subjected to some lights.

There is also the concept of coatings/lacquers which are designed to crack when a particular principal strain is exceeded.

If there exists such a paint as you have described, I would suspect it is in a research phase, or very expensive. But I could be wrong--I haven't done ESA in nearly decade.

Brad

 

[carefully]

Pontiac Motors used a similar technique in the early 60's. They applied a fairly thick layer of plastic material. Do not know how long they used it. GM later used a stress-coat process applied to plastic scale models for stress analysis. I believe FEA has replaced this type of testing, in most cases.