affix strain gauges across the joints?

@IFRs.. No.. I meant to check externally and control the tank (no internally).

I've never heard of a system like that.
Googling brings up this item: https://store.motionics.com/products/bluetooth-dia...
And another approach: https://www.sios-precision.com/en/products/length-...
I'm not familiar with either company or the pecifics of those products.
There are radar gauges used to detect liquid levels in tanks, and those vendors could tell you if their products could do this.

"Do all points dilate in a good way." That is a good question. But for starters, thermal expansion will vary up and down the tank, and be combined with growth from product loading. My guess: A large and moderately thick tank will behave pretty regularly, with dimensions being axisymmetric. On a smaller and/or thinner tank, you may have minor flat spots that move more than calculated when loaded. Of course, product movement and atmospheric conditions could give you hot spots and cold spots on the shell.
A tank being alternately heated and cooled could potentially "walk" to one side due to the cycling, which would complicate the instrumentation.

You could potentially do a one-time survey of hot vs cold dimensions to see how they vary over the tank, even if you don't normally monitor it all around. The tank strapping people might be able to help with that.

I do not have any idea for the size and service of the subject tank. However, assuming API tank ( not PV) having substantial size and height, I would prefer to work with an experienced surveying group .

Probable survey instruments would be digital theodolite or total station. The survey points on a grid should be marked on tank shell and survey shall be performed separate for cold and hot tank.

Tim was so learned that he could name a
horse in nine languages: so ignorant that he bought a cow to ride on.
(BENJAMIN FRANKLIN )

Multiple external strain guages all spaced around the vessel.

The 300C might get interesting with glue or the guages themselves.

Assume there is some sort of insulation?

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More worse, the strain gages will need to have temperature compensation gages installed on unstrained coupons exposed to the same temperatures.

Is the question how much expansion is due to temperature (which will be considerable) or due to internal pressure?

There is no way to measure "all points."

If your intent is to measure (or calculate) tank volume, there may be better ways to do that.

What size and sort of "tank" are we talking about here?

300C is rather high so will be quite interesting to see what this is.

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tank Diameter of 38 meters.. It is not my intent to calculate dilation but to check if all points in tank dilates correctly.

What's in it?

That's an enormous tank for something at 300C.

What sort of accuracy/ expansion are you looking to measure?

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What prevents it from dilating correctly?

I find it an excellent question and would be particularly interested in how such an instrumentation compares to our assumptions of how tanks work when they are filled. Sort of a real life validation of our assumptions. My first thought was to use laser scanning but that is much better from the inside and multiple setups around the outside is cumbersome, does not work through insulation and may yield variable results. Strain gauges would work but there would be a zillion of them and as mentioned by others the glue could be a problem. Super accurate volume measurements might work but they'd be an average and would not tell you what each weld seam was doing. Ultrasonics would be mucked up by the product.

Possibly due to lac of imagination, I keep coming back to the idea of strain gauges placed across both vertical and horizontal weld seams, many in the lower half of the bottom course and in the upper half of the top course as well as some in the middle of shell plate and at nozzles / manways, etc, particularly since they would work under the insulation, can be monitored and recorded remotely. You could get several cycles of the tank empty to full, heated to colled off, etc. You'd ahve to monitor setlement since that can affect shell deviations and be cognisant of temprorary events that disturbed the paterns (wind, etc).

It would make a great senior project or masters thesis - which might make it more affordable (??)

I wonder if motion amplification cameras can work at a very slow speed. I don't see any reason why not.

David

To get any decent sort of resolution on this though you're going to need a spot measurement at least every 1m around the circ.

So that's over 100 points there. At 38 m diameter this tank must be at least 10m high and probably higher, so you're talking about 1200 to 1500 points to measure to an accuracy of?? 2mm? 5mm?

that's a pretty big undertaking.

So the question goes back to why? Curiosity is a great thing but sometimes this can be knowledge for knowledge sake. What are you going to do with it?

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Also: If you get a response it's polite to respond to it.