#### Command list

• Input handling
• Solution control and techniques
• Output
• Mesh commands
• Nodes and connectivity
• Material properties
• Initial conditions
• Boundary conditions
• Contact and tied interfaces
• Rigid bodies
• Connectors
• Parameters and functions
• Geometries
• Sets
• Coordinate system
• Particle
• SPH

### PART

###### Nodes and connectivity
*PART
"Optional title"
pid, mid, eosid, $h$, $\alpha_{max}$, $\Delta t^{erode}$, $\epsilon_{geo}^{erode}$, $\epsilon_v^{erode}$, perode

#### Parameter definition

VariableDescription
pid Unique part identification number or range of parts
mid Material identification number
eosid Equation-of-state identification number
default: equation-of-state is not used
$h$ 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
$\epsilon_{geo}^{erode}$ Effective deviatoric geometric strain above which elements are eroded
default: 1.0e20
$\epsilon_v^{erode}$ Volumetric strain above which elements are eroded
default: 1.0e20
perode Flag to activate conversion of eroded elements to discrete particles
options:
0 $\rightarrow$ mass of eroded elements disappears
1 $\rightarrow$ mass of eroded elements is replaced by discrete particles

#### 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 Afea Solver GUI.

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

$\displaystyle{ \epsilon_{geo} = \sqrt{ \frac{2}{3} \mathbf{\epsilon}_{dev} : \mathbf{\epsilon}_{dev} }}$

where $\mathbf{\epsilon}_{dev}$ 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.

#### 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