# zone.field.quantity

Syntax

s := zone.field.quantity
zone.field.quantity = s

Get/set the scalar quantity to retrieve when the value being obtained is a tensor. This value is ignored if the type is not a tensor. The available quantity names are listed in the following table.

Quantity Name

Description

intermediate

intermediate principal stress

maximum

the maximum (most positive) value of principal stress (note that compressive stresses are negative in FLAC)

mean

the mean pressure value defined as the trace of the tensor divided by 3. For stresses this is most often referred to as the pressure.

minimum

the minimum (most negative) principal stress (note that compressive stresses are negative in FLAC)

norm

The norm of the strain rate; see the equations below

octahedral

octahedral stress; see the equations below

shear-maximum

maximum shear stress

total-measure

distance of tensor value to the origin in principal space

volumetric

volumetric change or trace

von-mises

Von Mises measure; see the equations below

xx

$$xx$$-component of the tensor

xy

$$xy$$-component of the tensor

xz

$$xz$$-component of the tensor

yy

$$yy$$-component of the tensor

yz

$$yz$$-component of the tensor

zz

$$zz$$-component of the tensor

Returns:

s - the name of the scalar quantity to retrieve from the tensor

Accepts:

s - the name of the scalar quantity to retrieve from the tensor. Keyword matching rules are used. If no match is found, an error occurs.

Table 2: Equations for Zone Field Quantities

Quantity Name

Stress

Strain Increment

Strain Rate

norm

$$\sqrt{\sigma_{kk}}$$

$$\sqrt{{\epsilon^i}_{kk}}$$

$$\sqrt{{\epsilon^r}_{kk}}$$

octahedral

$$\sqrt{{2 \over 3} J_2}$$

$$\sqrt{{8 \over 3} J^i_2}$$

$$\sqrt{{8 \over 3} J^r_2}$$

von-mises

$$\sqrt{3J_2}$$

$$\sqrt{{4 \over 3} J^i_2}$$

$$\sqrt{{4 \over 3} J^r_2}$$