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Is there anyway to measure the young's modulus with a compressive force on a paper thin elastic sheet (made out of a rubbery-fabric material)? I wish to compress the sheet in an orientation that brings two opposite outer edges of the sheet towards each other, rather than a compression that flattens the sheet to be slightly thinner than "paper thin". However, I don't want the sheet to simply fold as this compression is applied. How could one construct some sort of a holding mechanism that keeps the sheet from folding, and directs all of the compressive force into truly compressing the sheet in the desired direction?

The sheet I am working with has an adhesive on one side. The best solution I can think of is to take a large block of some easily compressible material and measure the compressive stress strain relationship of the block with and without the sheet adhered to a side face of the block. If this was done, would the stress on the sheet be the stress on the sheet + block system minus the stress that the block has been measured to experience under a certain strain? I assume this would hold because stress is force over area which means it is additive. If this is true, what material would you all recommend I use for the block?

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  • $\begingroup$ Maybe do one sheet on each side of the block and average out the result? $\endgroup$
    – Farris
    Mar 17 at 13:09

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The DMA (Dynamic Mechanical Analyzer) manipulates a small "record needle" (like an AFM) that vibrates against the material. The temperature is also controlled to measure the modulus as a function of T.

Placement of the needle is microscopically aided.

Recommend potting a small sample and creating a thin orthogonal section (cut and polish) for testing thereby compressing in the axis of interest.

Maybe the sheet can be fabricated thicker without altering the base properties of the material. Or, several sheets can be sandwiched together and potted as above for sectioning (although that incorporate the modulus of other axes in the results).

See: tainstruments.com/dma-850 and mts.com for more info.

As an alternative, I am sure a testing faculty can be contracted to test the material for you

(You can also infer the percentage of crystallinity present in a liquid plastic polymer sample (Vectra from the 80's or PCTFE (for example)) where an amorphous nature is locked in by cooling during fabrication. At a temperature above the threshold the material would transform relatively slowly to 100% crystalline nature thereby making it more brittle.)

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