# Are Green strain calculations apt for volumetric strains?

I am trying to calculate large volumetric strains but I am somewhat confused whether Green strain is the right thing to be using or whether I should use good old-fashioned engineering strain.

The work I am doing is looking at strain of a deformable pipe. I am measuring longitudinal ($L_s$), circumferential ($C_s$) and volumetric ($V_s$) strain. As the strains are large and I want to avoid errors due to rotations, I have opted to use the Green-Lagrange strain tensor for the $L_s$ and $C_s$ in the form

\begin{equation} \frac{d\mathbf{x}^2-d\mathbf{X}^2}{2d\mathbf{X}^2} \end{equation}

Where $X$ represents the undeformed configuration and $x$ the deformed configuration.

I'm pretty sure that I should be using normal engineering strain for the volume but I just want some clarification.

• You have to use a consistent strain measure for all your strain calculations. Any of the Seth-Hill family of strains will do. The logarithmic (Hencky) strain is the most physically intuitive measure. Oct 24, 2015 at 3:33