EROSION_CRITERION_SPH_DRIVEN
Solution control and techniques
*EROSION_CRITERION_SPH_DRIVEN
"Optional title"
coid
pid, $D^{erode}$, $\varepsilon_{eff}^{p,erode}$, $R$
"Optional title"
coid
pid, $D^{erode}$, $\varepsilon_{eff}^{p,erode}$, $R$
Parameter definition
Variable
Description
coid
Command ID
pid
Part ID
$D^{erode}$
Damage threshold for erosion
$\varepsilon_{eff}^{p,erode}$
Effective plastic strain threshold for erosion
$R$
Erosion radius
Description
This command erodes elements based on damage or plastic strain accumulated in nearby SPH nodes. It requires that the SPH nodes have been generated using the Erode-to-SPH (E2S) procedure. The intent is to activate E2S well ahead of advancing crack fronts or regions undergoing significant plastic deformation.
Elements with centers of gravity within $R$ of an SPH node exceeding the damage or plastic-strain thresholds are eroded.
Example
Fracture toughness specimen
A model of a simple fracture toughness test specimen. Elements are eroded as the crack grows. Note that the SPH nodes have a residual strength even after reaching full damage (res_SPH$=0.01$). This prevents a local disintegration of the material along the crack.
*UNIT_SYSTEM
SI
*PARAMETER
L = 0.08, "Specimen size"
W = 0.002, "Specimen width"
R = 0.005, "Tool radius"
dx = 0.001, "Element size"
tend = 0.001, "Termination time"
disp = 0.002, "Tool displacement"
res_SPH = 0.01, "Residual strength (SPH)"
#
# --- TIME ---
#
*TIME
[%tend]
#
# --- MESH ---
#
*COMPONENT_BOX
"specimen - 1"
1, 1, [0.5*%L/%dx], [0.5*%L/%dx], [%W/%dx]
[-%L], [-%L/2], [-%W/2], [-%L/2], [-%W/2], [%W/2]
*COMPONENT_BOX
"specimen - 2"
2, 1, [0.5*%L/%dx], [%W/%dx], [%W/%dx]
[-%L], [-%W/2], [-%W/2], [-%L/2], [%W/2], [%W/2]
*COMPONENT_BOX
"specimen - 3"
3, 1, [0.5*%L/%dx], [0.5*%L/%dx], [%W/%dx]
[-%L], [%W/2], [-%W/2], [-%L/2], [%L/2], [%W/2]
*COMPONENT_BOX
"specimen - 4"
4, 1, [0.5*%L/%dx], [0.5*%L/%dx], [%W/%dx]
[-%L/2], [-%L/2], [-%W/2], 0, [-%W/2], [%W/2]
*COMPONENT_BOX
"specimen - 5"
5, 1, [0.5*%L/%dx], [0.5*%L/%dx], [%W/%dx]
[-%L/2], [%W/2], [-%W/2], 0, [%L/2], [%W/2]
*MERGE_DUPLICATED_NODES
P, 1, P, 1, [%dx/100]
*TRIM_HOLE
1
P, 1, 100, [2.02*%R], [%W]
*TABLE
100, 7
1, [-3*%R], [%L/2-3*%R], [-%W], 0, 0, 1
2, [-3*%R], [-%L/2+3*%R], [-%W], 0, 0, 1
*COMPONENT_PIPE
"tool top"
6, 2, [%W/%dx], 24, 1
[-3*%R], [%L/2-3*%R], [-%W], [-3*%R], [%L/2-3*%R], [%W], [%R]
*COMPONENT_PIPE
"tool bottom"
7, 3, [%W/%dx], 24, 1
[-3*%R], [-%L/2+3*%R], [-%W], [-3*%R], [-%L/2+3*%R], [%W], [%R]
*CHANGE_P-ORDER
PS, 23, 2
*SMOOTH_MESH
PS, 23, 45.0
*SET_PART
23
2, 3
#
# --- MATERIAL ---
#
*MAT_METAL
"brittle steel"
1, 7800.0, 210.0e9, 0.3, 1
1
0
[%res_SPH]
*FUNCTION
1
1.5e9 + 1.5e9 * epsp^0.3
*PROP_DAMAGE_CL
1
1.0e8, 5.0e4
*MAT_RIGID
"tool"
2, 7800.0
#
# --- EROSION ---
#
*EROSION_CRITERION
1
P, 1
0.9
*EROSION_CRITERION_SPH_DRIVEN
1
1, 0.8, 0, [3*%dx]
#
# --- PART ---
#
*PART
"specimen"
1, 1
"tool top"
2, 2
"tool bottom"
3, 2
#
# --- BC ---
#
*BC_MOTION
"tool top"
2
P, 2, ZX, XYZ
V, Y, 100
*BC_MOTION
"tool bottom"
3
P, 3, ZX, XYZ
V, Y, 100, -1
*FUNCTION
100
smooth_v(%disp, 0, %tend)
#
# --- CONTACT ---
#
*CONTACT
"all to all"
1
ALL, 0, ALL, 0, 0.2, 1.0e14
#
# --- SPH ---
#
*PARTICLE_DOMAIN
ALL, 0
[-2*%L], [-%L], [-%L], [%L], [%L], [%L]
*PARTICLE_SPH
"specimen"
1, 400000
1, 1, 0, 0, 0, 1
[%dx/5]
*GEOMETRY_PART
"specimen"
1
1
*END
