Ask the Expert

Question

Dear David

Which is the most accurate way to measure the extension on a dimpled sample in a tensile test? It seems the normal (contact) extensometer would be difficult to measure the gauge length because of the dimpled surafes of the sample. Would the optical or non-contacting or any other versions be more accurate?

Many thanks in advance,

Regards

Bac Nguyen

Answer

Dear Bac Nguyen,

Please advise what the material is, dimensions of the test sample, expected maximum load and extension and what calculations/results you are looking for.

The laser scanning extensometer is ideal for medium to high extension material but is not suitable for Proof Stress or Young’s Modulus measurements on metal test pieces

Regards

David