Command manual

Command list

CONNECTOR_DAMPER

Mesh commands
*CONNECTOR_DAMPER
"Optional title"
coid
pid${}_1$, pid${}_2$, csysid, $R$, $h$, $m$, $\eta$, $k_{max}$
cid${}_{axial}$, cid${}_{shear}$, cid${}_{bend}$, cid${}_{rate}$

Parameter definition

VariableDescription
coid Command ID
pid${}_1$ Part ID 1
pid${}_2$ Part ID 2
csysid Coordinate system defining location and direction of damper
$R$ Damper radius
$h$ Damper height
$m$ Damper mass
$\eta$ Hysteresis factor
default: no hysteresis
$k_{max}$ Maximum tangential stiffness
default: no limit
cid${}_{axial}$ CURVE defining axial force versus compression
cid${}_{shear}$ CURVE defining shear force versus shear displacement
cid${}_{bend}$ CURVE defining bending moment vesus bending angle
default: no bending stiffness
cid${}_{rate}$ CURVE defining rate hardening in compression and shear
default: not used

Description

This command is used to model the effect of a rubber damper between two parts (pid${}_1$ and pid${}_2$). The nodes enclosed inside the cylinder defined by csysid, $R$ and $h$ are used to calculate the damper deformations. The computed forces are distributed to the same set of nodes.

The hysteresis parameter $\eta$ is a scalar between 0 and 1. It tells by how much the forces are reduced during unloading. $\eta=0.2$ means that the unloading force is 20% lower than during loading.

$k_{max}$ limits the tangential stiffness. It is primarily used to prevent discrete jumps in force when oscillating between loading and unloading.

Example

Axially loaded damper (quasi-static and at velocity 1m/s)

As complete model whith a damper between two plates. It is first compressed and then loaded in tension.


*UNIT_SYSTEM
SI
*PARAMETER
L = 0.1, "plate size"
H = 0.01, "plate thickness"
R = 0.02, "damper radius"
h = 0.02, "damper height"
m = 0.01, "damper mass"
eta = 0.3, "hysteresis parameter"
k_max = 1.0e6, "max tangential stiffness"
v = 1.0, "velocity"
*TIME
[0.015/%v], 0, 0, [1.0e-5/%v]
#
# --- MESH ---
#
*COMPONENT_BOX
"base plate"
1, 1, 5, 5, 1
[-%L/2], [-%L/2], 0, [%L/2], [%L/2], [%H]
*COMPONENT_BOX
"top plate"
2, 2, 5, 5, 1
[-%L/2], [-%L/2], [%h+%H], [%L/2], [%L/2], [%h+2*%H]
#
# --- MATERIAL ---
#
*MAT_RIGID
"steel"
1, 7800.0
#
# --- PART ---
#
*PART
"base plate"
1, 1
"top plate"
2, 1
#
# --- DAMPER ---
#
*CONNECTOR_DAMPER
1
1, 2, 100, [%R], [%h], [%m], [%eta], [%k_max]
101, 102, 103, 104
*COORDINATE_SYSTEM_FIXED
100, 0, 0, [%H+%h/2]
1, 0, 0, 0, 1, 0
*CURVE
"axial force versus compression"
101
-0.001, -100.0
0.0, 0.0
0.001, 150.0
0.002, 400.0
0.003, 750.0
0.004, 1200.0
0.005, 1750.0
0.006, 2750.0
*CURVE
"shear force versus displacement"
102
0.0, 0.0
0.001, 50.0
*CURVE
"bending moment versus angle"
103
0.0, 0.0
0.1, 40.0
*CURVE
"rate hardening"
104
0.0, 1.0
1.0, 1.5
2.0, 1.75
4.0, 2.0
5.0, 2.0
#
# --- PRESCRIBED MOTION ---
#
*BC_MOTION
"base plate"
1
P, 1, XYZ, XYZ
*BC_MOTION
"compression"
2
P, 2, XY, XYZ
V, Z, 1000
*CURVE
"compression"
1000
0, [-%v]
[0.0049999/%v], [-%v]
[0.0050001/%v], [%v]
[1.0/%v], [%v]
*END