Commands list

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PART

Nodes and connectivity

*PART
"Optional title"
pid, mid, -, $h$, $\alpha_{max}$, $\Delta t^{erode}$, $\varepsilon_{geo}^{erode}$, $\varepsilon_v^{erode}$, $N_{perode}$, $R_{perode}$, $\Delta t_{perode}$

Parameter definition

Variable
Description
pid
Unique part identification number or range of parts
mid
Material identification number
-
Reserved
$h$
Shell thickness (only used for mass calculation, not in contact) or rebar diameter
default: 1
$\alpha_{max}$
External element face smoothing angle
default: no surface smoothing, i.e. ang_smooth = $0^\circ$
$\Delta t^{erode}$
Time step size below which elements are eroded
default: 0
$\varepsilon_{geo}^{erode}$
Effective deviatoric geometric strain above which elements are eroded
default: 1.0e20
$\varepsilon_v^{erode}$
Volumetric strain above which elements are eroded
default: 1.0e20
$N_{perode}$
Number of particles (used to replace eroded elements with discrete particles)
$R_{perode}$
Particle radius (used to replace eroded elements with discrete particles)
default: $10\%$ of average element size
$\Delta t_{perode}$
Life span of particles
default: Inifinite

Description

The command is used to assign properties to a part or to a range of parts. Surface smoothing is applied if the angle between the normal vectors of two adjacent higher order external faces is smaller than $\alpha_\mathrm{max}$. Part commands can be assigned a title. The title shows up in part.out and in the part list in IMPETUS Solver GUI.

An element is eroded if its critical time step drops below $\Delta t^{erode}$, if the effective deviatoric geometrical strain $\varepsilon_{geo}$ reaches $\varepsilon_{geo}^{erode}$ in at least one integration point, or if the volumetric strain exceeds $\varepsilon_v^{erode}$. The effective deviatoric geometric strain is defined as:

$\displaystyle{ \varepsilon_{geo} = \sqrt{ \frac{2}{3} \boldsymbol{\varepsilon}_{dev} : \boldsymbol{\varepsilon}_{dev} }}$

where $\boldsymbol{\varepsilon}_{dev}$ is the deviatoric strain tensor. Note that elements can also be eroded at material failure if setting the erosion flag to 1 in the damage property command.

$N_{perode}$ is specified if eroded elements are to be replaced by discrete particles. With this option activated it is also necessary to define the PARTICLE_DOMAIN command.

Example

PART

The following input assigns the material with ID 100 to all parts with ID's in the range 1 to 5 and to part 14.

*PART "this is a part title" [1..5, 14], 100