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ACTIVATE_ELEMENTS

Mesh commands

*ACTIVATE_ELEMENTS
"Optional title"
coid, entype, enid, $t_{birth}$, $t_{death}$, $\xi$

Parameter definition

Variable
Description
coid
Command ID
entype
Entity type
options: ES, G, GS, P, PS
enid
Entity ID
$t_{birth}$
Time or FUNCTION defining element activation
$t_{death}$
Time or FUNCTION defining element deactivation
$\xi$
Optional strength of not yet activated elements
default: 0

Description

This command lets the user activate or deactivate elements at a pre-defined time or on a certain signal. If a FUNCTION is used an element is activated or deactivated on function values > 0.

The optional constant $0 \le \xi \le 1$ is used to scale the internal forces of unactivated elements. $\xi$ is typically used in situations where nodes of unactivated elements are part of a MERGE interface and where the nodes need to be active from time 0 to avoid the formation of gaps. A typical application is weld seams where the weld elements need to follow the deformation of the base material. Else they will not be activated at the correct location.

Example

Multiple activations/deactivations with function

An element is activated/deactivated each time the element in motion is in close proximity to it with function ID 1000 and 2000.

*PARAMETER %tend = 0.05, "Termination time" %L = 0.1, "Element side length" %S = 0.2, "Distance between boxes" %n = 4, "Number of boxes" *TIME [%tend], , , [%tend/10000] *OUTPUT [%tend/100] *UNIT_SYSTEM SI ~repeat [%n] *COMPONENT_BOX [r1], [r1], 1, 1, 1 [(r1-1)*(%L+%S)], 0, 0, [r1*%L+(r1-1)*%S], [%L], [%L] *OUTPUT_SENSOR [r1], [r1], [(r1-1)*(%L+%S)+(%L/2)], [%L/2], [%L/2] *PART [r1], 1 ~end_repeat *MAT_ELASTIC 1, 7800, 210e9, 0.3 *INITIAL_VELOCITY P, 2, 100 *CHANGE_P-ORDER ALL, 0, 3 *BC_MOTION ALL, 0, YZ *SET_PART 134 1, 3, 4 *BC_MOTION PS, 134, X *CONTACT 1 ALL, 0, ALL, 0 # # --- ACTIVATE ELEMENTS --- # *ACTIVATE_ELEMENTS 1, P, 3, fcn(1000), fcn(2000) *FUNCTION 1000 abs(xs(3)-xs(2))-%L *FUNCTION 2000 -(abs(xs(2)-xs(3))-%L) *END
Deactivation with coordinates

ACTIVATE_ELEMENTS is used to remove elements at the end of the bar as they go outside the range defined in function ID 222.

*UNIT_SYSTEM SI *TIME 0.001 *COMPONENT_BOX 1, 1, 30, 4, 4 -0.15, -0.01, -0.01, 0.15, 0.01, 0.01 *MAT_METAL 1, 7800.0, 210.0e9, 0.3 1 *FUNCTION 1 1.0e9 + 1.0e9*epsp^0.4 *PART 1, 1 *INITIAL_VELOCITY P, 1, fcn(123) *FUNCTION 123 4.0e3*x # # --- DEACTIVATING ELEMENTS --- # *ACTIVATE_ELEMENTS "remove elements at the ends" 1, P, 1, 0, fcn(222) *FUNCTION 222 H(abs(x) - 0.18) *END
Deactivation with damage

ACTIVATE_ELEMENTS is used to remove elements based on damage. Element set ID 123 is evaluated in function ID 333. The elements in the element set are deactivated as the damage value exceeds 0.6.

*UNIT_SYSTEM SI *PARAMETER %tend = 0.0001, "Termination time" *TIME [%tend], , , [%tend/1000] *COMPONENT_BOX 1, 1, 30, 2, 2 -0.15, -0.01, -0.01, 0.15, 0.01, 0.01 *MAT_METAL 1, 7800.0, 210.0e9, 0.3, 1 1 *PROP_DAMAGE_CL 1, 1 500.0e6 *FUNCTION 1 1.0e9 + 1.0e9*epsp^0.4 *PART 1, 1 *INITIAL_VELOCITY P, 1, fcn(123) *FUNCTION 123 3.0e3*x # # --- DEACTIVATING ELEMENTS --- # *ACTIVATE_ELEMENTS "remove elements based on damage" 1, ES, 123, 0, fcn(333) *SET_ELEMENT 123 15, 16, 45, 46, 75, 76, 105, 106 *FUNCTION 333 H(dmg_es(123)-0.6) *END