strain units in postview

[NataCalc]

Hi,

What is unit for strain in postview: mm/mm or %

Cheers,
Nataliya

[maas]

Hi Nataliya,

Strain is unitless since it is a ratio of two lengths. The unit of length does not matter since the strain value would be the same regardless of the length unit.

Cheers,

Steve

[NataCalc]

Hi Steve,

My unit system is mm for geometries of objects, in Neo-Hookean model I used MPa for Young’s modulus and scalar value for poison ration (0.49). My intention was to use poisson ratio over 0.5 as ligament is almost incompressible but FEBio does not allow doing it.

As results, I obtain max 50 MPa effective stress (von misses stress) and 0.6-0.8 for Lagrange strain (strains). If strain is unitless (mm/mm), I obtain very unrealistic strain of 60%-80% as physiological strain range is between 5-10%. Is it an indicator that I have to use different material model which will better describe material properties of ligament?

Cheers,
Nataliya