Because practicality. Strain generally occurs across mm scales at most for most traditional tensile tests and relevant materials. Normally it’s actually much less than mm. Occasionally you see micrometers/micrometers.
Because excel doesn’t have built in unit handling so when you enter in readings from the strain gauge you’ll probably enter them in what’s being reported.
You can write the units of strain however you like, I often say ul for unitless.
Because practicality. Strain generally occurs across mm scales at most for most traditional tensile tests and relevant materials. Normally it’s actually much less than mm. Occasionally you see micrometers/micrometers.
How is it more practical when 1 m/m = 1 mm/mm = 1 μm/μm?
The original specimens and data are usually in mm, not meters so mm/mm makes more sense than m/m, although you do have a point
Because excel doesn’t have built in unit handling so when you enter in readings from the strain gauge you’ll probably enter them in what’s being reported.
You can write the units of strain however you like, I often say ul for unitless.