# zone.tetra.strain.increment

Syntax

t := zone.tet.strain.inc(z<,ioverlay><,itetra>)

Get the zone tetra strain increments based on the current displacement field.

If ioverlay is specified (an integer from 1 to 2) then only the strain increments of the tetra of that overlay are returned. If itetra is specified as well, then only the strain increments of that specific tetra is returned.

The total number of tetra in each overlay depends on the zone type (brick, degenerate-brick, wedge, pyramid, or tetrahedron). See also the functions zone.overlays and zone.tet.num.

Returns: t - zone tetra strain increment tensor or value z - zone pointer ioverlay - the overlay index of the tetra, from 1 to 2 itetra - the index of the tetra in the overlay i1 - optional tensor index that, if given without i2, ranges from 1 to 7, accessing the $$xx$$, $$yy$$, $$zz$$, $$xy$$, $$xz$$, and $$yz$$ tensor values. i2 - optional tensor notation that must be given with i1. In this case, i1 corresponds to the first index of the tensor position and i2 to the second in the row/column format. For instance, i1 = 1 and i2 = 3 returns the $$xz$$ tensor value.