zone initialize command

Syntax

zone initialize keyword <range>

Primary keywords:

density    extra    state    stress    stress-principal    stress-xx    stress-xy    stress-xz    stress-yy    stress-yz    stress-zz

Initialize a variable on all zones in the range.

Note that among the keywords, there is similarity between the stress xx construction of the command and the stress-xx construction. The difference is that the former will allow multiple components to be specified at once (e.g., zone initialize stress xx 1 yy 2.4 zz 4.7) but cannot take a value modifier (that is, vary, multiply, etc.). Also be aware that when this command form is used, the entire stress tensor is initialized—any components not specified explicitly are assumed to be zero. The latter construction allows modifiers (e.g., zone.initialize.stress-yy 2.2 add 3) but each component must be separately specified.

Note that in FLAC, compressive stresses are negative.

density f [zoneinitializeblock]

Mass density of zone.

extra i a[zoneinitializeblock]

Extra variable for array index i.

state i [zoneinitializeblock]

The plasticity indicators for tetrahedrons are set to i . Normally the value of i used is 0 in order to reset the failure indicators.

stress <keyword ...>

Full stress state, specified by component. A component that is not specified is assumed to be zero. This command should be used after assigning a constitutive model.

xx f

xx-component of stress.

xy f

xy-component of stress.

xz f (3D Only)

xz-component of stress.

yy f

yy-component of stress.

yz f (3D Only)

yz-component of stress.

zz f

zz-component of stress.

stress-principal <keyword ...>

Principal stress states, specified by value and by direction using the available keywords. Note that at least two directions must be specified, and magnitudes not specified are assumed to be zero. Note that the [zoneinitializeblock] is available after each of the following keywords, allowing them to be varied in space independently. This command should be used after assigning a constitutive model.

direction-intermediate v [zoneinitializeblock]

Direction of intermediate principal stress.

direction-maximum v [zoneinitializeblock]

Direction of maximum principal stress.

direction-minimum v [zoneinitializeblock]

Direction of minimum principal stress.

intermediate f [zoneinitializeblock]

Intermediate principal stress magnitude.

maximum f [zoneinitializeblock]

Maximum (most postitive) principal stress.

minimum f [zoneinitializeblock]

Minimum (most negative) principal stress.

dip-maximum f (3D Only)

Set dip of maximum principal stress. Dip and dip-direction can be given instead of the vector orientation. Orientations only need to be specified for two principal components.

dip-direction-maximum f (3D Only)

Set dip direction of maximum principal stress. Dip and dip-direction can be given instead of the vector orientation. Orientations only need to be specified for two principal components.

dip-intermediate f (3D Only)

Set dip of intermediate principal stress. Dip and dip-direction can be given instead of the vector orientation. Orientations only need to be specified for two principal components.

dip-direction-intermediate f (3D Only)

Set dip direction of intermediate principal stress. Dip and dip-direction can be given instead of the vector orientation. Orientations only need to be specified for two principal components.

dip-minimum f (3D Only)

Set dip of minimum principal stress. Dip and dip-direction can be given instead of the vector orientation. Orientations only need to be specified for two principal components.

dip-direction-minimum f (3D Only)

Set dip direction of minimum principal stress. Dip and dip-direction can be given instead of the vector orientation. Orientations only need to be specified for two principal directions.

stress-xx f [zoneinitializeblock]

xx-component of stress (See the description above for the difference between zone initialize stress-xx and zone initialize stress xx and for the next five keywords).

stress-xy f [zoneinitializeblock]

xy-component of stress.

stress-xz f (3D Only) [zoneinitializeblock]

xz-component of stress.

stress-yy f [zoneinitializeblock]

yy-component of stress.

stress-yz f (3D Only) [zoneinitializeblock]

yz-component of stress.

stress-zz f [zoneinitializeblock]

zz-component of stress.

zone initialize Keyword Block

The following keywords may be used to modify a supplied value. If the description of the modifier keyword mentions what type of value it may be applied to (e.g., scalar value, vector value, etc.), be sure there is a match between the modifier and the main keyword value. The commands main keywords are: density, extra, state, stress-xx, stress-xy, stress-xz, stress-yy, stress-yz and stress-zz. direction-intermediate, direction-maximum, direction-minimum, intermediate, maximum and minimum.

add

Add the specified value to the existing value.

gradient v <origin v >

Apply a gradient to the scalar-value provided. Note the origin keyword is optional, however, the default value (0,0,0) is used if the origin keyword is not included in the command — which may not produce the intended result.

multiply

Multiply the existing value by the specified value.

vary v

Apply a linear variation to the scalar-value provided.

Usage Example

The following examples illustrate how zone initialize can be used

zone initialize stress-xx -100 stress-yy -200 stress-zz -300

zone initialize stress-principal minimum -300 intermediate -200 ...
     maximum -100 direction-minimum 1 1 0 direction-intermediate 0 1 0