# measure history command

Syntax

measure history <id id > keyword ...

Primary keywords:

Add a measure history. A history is a floating point variable that can be sampled and stored during a model run. The optional id directly following history creates a history with the specified ID. If not specified, then the next available history ID is used. Following one of the keywords given below, either 1) a position vector or 2) an additional id keyword must be given to define the specific measurement object. Review the common c history commands for details regarding the manipulation of histories.

coordination [measurehistoryblock]

Coordination, or average number of contacts per body, inside the measurement object.

porosity [measurehistoryblock]

Porosity inside the measurement object.

position-x [measurehistoryblock]

$$x$$-position of the measurement object.

position-y [measurehistoryblock]

$$y$$-position of the measurement object.

position-z (3D only) [measurehistoryblock]

$$z$$-position of the measurement object.

strainrate [measurehistoryblock]

The measurement strain rate. Use the quantity keyword to specify the quantity to be recorded.

strainrate-xx [measurehistoryblock]

xx-component of the strain rate inside the measurement object.

strainrate-xy [measurehistoryblock]

xy-component of the strain rate inside the measurement object.

strainrate-xz (3D only) [measurehistoryblock]

xz-component of the strain rate inside the measurement object.

strainrate-yx [measurehistoryblock]

yx-component of the strain rate inside the measurement object.

strainrate-yy [measurehistoryblock]

yy-component of the strain rate inside the measurement object.

strainrate-yz (3D only) [measurehistoryblock]

yz-component of the strain rate inside the measurement object.

strainrate-zx (3D only) [measurehistoryblock]

zx-component of the strain rate inside the measurement object.

strainrate-zy (3D only) [measurehistoryblock]

zy-component of the strain rate inside the measurement object.

strainrate-zz (3D only) [measurehistoryblock]

zz-component of the strain rate inside the measurement object.

stress [measurehistoryblock]

The measure stress. Use the quantity keyword to specify the quantity to be recorded.

stress-xx [measurehistoryblock]

xx-component of the stress inside the measurement object.

stress-xy [measurehistoryblock]

xy-component of the stress inside the measurement object.

stress-xz (3D only) [measurehistoryblock]

xz-component of the stress inside the measurement object.

stress-yx [measurehistoryblock]

yx-component of the stress inside the measurement object.

stress-yy [measurehistoryblock]

yy-component of the stress inside the measurement object.

stress-yz (3D only) [measurehistoryblock]

yz-component of the stress inside the measurement object.

stress-zx (3D only) [measurehistoryblock]

zx-component of the stress inside the measurement object.

stress-zy (3D only) [measurehistoryblock]

zy-component of the stress inside the measurement object.

stress-zz (3D only) [measurehistoryblock]

zz-component of the stress inside the measurement object.

measure history Keyword Block

The following modifiers are available to specify addition information for the measure history keywords. They will not modify history values to which they are not applicable. In other words, the component keyword will not modify scalar or tensor values. coordination, porosity, position-x, position-y, position-z, radius, strainrate, strainrate-xx, strainrate-xy, strainrate-xz, strainrate-yx, strainrate-yy, strainrate-yz, strainrate-zx, strainrate-zy, strainrate-zz, stress, stress-xx, stress-xy, stress-xz, stress-yx, stress-yy, stress-yz, stress-zx, stress-zy and stress-zz.

component keyword

This keyword selects which scalar to retrieve from a vector type value, such as velocity or displacement. If the value type is not a vector, this setting is ignored. The available options are:

x
Record the $$x$$-component of the vector.
y
Record the $$y$$-component of the vector.
z (3D ONLY)
Record the $$z$$-component of the vector.
magnitude
Record the vector magnitude.
id i

Record the history of measure with ID i.

index i

For keywords that require it (most notably extra), this specifies the index that should be used.

log b

If on, the returned number is the base 10 log of the absolute value of the original value. The default is off.

position v

Record the history of measure either containing or closest to position v.

quantity keyword

This keyword selects which scalar to retrieve from a symmetric tensor type value, such as stress or strain. If the value type is not a tensor, this setting is ignored. The available options are:

intermediate (3D ONLY)

Record the intermediate principal value of the tensor.

maximum

Record the maximum (most positive) principal value of the tensor. Note that compressive stresses are negative.

mean

Record the mean value, defined as the trace of the tensor divided by { 2 in 2D; 3 in 3D}. For stresses this is most often referred to as the pressure.

minimum

Record the minimum (most negative) principal value of the tensor. Note that compressive stresses are negative.

norm

Record the norm of the full tensor. This is defined as the sum of each tensor component squared.

octahedral (3D ONLY)

Record the octahedral measure of the tensor.

shear-maximum

Record the maximum shear value.

total-measure (3D ONLY)

Record the distance of the tensor value to the origin in principal space.

volumetric

Record the volumetric change, or trace of the tensor.

von-mises (3D ONLY)

Record the Von Mises measure.

xx

Record the xx-component of the tensor.

xy

Record the xy-component of the tensor.

xz (3D ONLY)

Record the xz-component of the tensor.

yy

Record the yy-component of the tensor.

yz (3D ONLY)

Record the yz-component of the tensor.

zz (3D ONLY)

Record the zz-component of the tensor.

type keyword

In certain cases the type (scalar, vector, or tensor) of the value cannot necessarily be determined ahead of time. Extra variables, for example, can hold values of all three types. This keyword allows one to specify which type it is assumed to be. If the original value type does not match, 0.0 is returned.

scalar

Specify a scalar float type.

tensor

Specify a tensor type.

vector

Specify a vector type.