Zone Maximum Shear Strain Increment in Flac2D

FLAC
1

I am modeling a seismic site response analysis in FLAC2D, applying only the horizontal component of ground motion at the base. In the results, I can see the plot Maximum Shear Strain Increment, which I understand corresponds to SSI values. However, when I compare these results with the engineering shear strain defined as γ=sqrt(4J2)=2×SSI=2xzone.strain.shear.inc, both values appear to be very similar.

My question is: In FLAC2D, is the “ZONE MAXIMUM SHEAR STRAIN INCREMENT” plot actually reporting the engineering shear strain, or is it strictly the shear strain intensity (SSI)?

2

The zone maximum shear strain increment in the plot is defined by e3-e1, and the SSI is the square root of the second invariant of the strain increment deviator.

All definitions are listed in the table from the link below:

Stress/Strain Invariants — Itasca Software 9.4 documentation