strain vs deformation

[kvvic]

hi everyone!

 

I'm a translator, doing a translation of a scientific paper, and I need your help as specialists. Hope this won't be considered a flame here.

 

Do you make any difference between strain and deformation in technical discussions, especially in scientific writing? I saw different usages, e.g., Wikipedia says strain is a geometrical expression of deformation, while Britannica uses them interchangeably. Is it correct for a scientific paper to say that "... deformation of ... is calculated..." or is it more accurate to use "described" or "characterized" instead?

 

I often run into this issue in my work and don't know who I should trust. So, where's the truth? Could you be the ultimate authority?

[Mokele]

In an engineering context, when you subject a material to force, it deforms. You could express this deformation in absolute terms ("the steel sample lengthend by 0.01 mm when under 200N of force"), but it's often more useful to express it as a percentage, called strain (thus, if the above steel sample was 10mm long, that would be 0.001 poissons, a 0.1% elongation). The advantage to using 'strain' is that, since it's in purely relative terms, if you also express force relative to cross-sectional area, you get a relationship that holds true across all sizes (the same force per unit cross sectional area will produce the same % deformation, regardless of size).

 

So, in shot, strain is relative deformation.

 

Mokele

[kvvic]

Mokele

Thanks for your explanation, clear and very useful. I'll keep it in mind for the future.