The compressive longitudinal strain

[ahmeeeeeeeeee]

Hello,

is the strain defined as the absolute deformation to the initial ? i.e is it always positive ??

If Yes , then poission's ration is negative for compression of ordinary materials ?

 

[LawrenceC]

Strain is defined as belowl

e = (a - b)/b

where b is original length and a is the stressed length. So it can be negative for compressive loading. Absolute does not mean |absolute value|.