## 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

Variable
Description
coid
Command ID
pid${}_1$
Part ID 1
pid${}_2$
Part ID 2
csysid
Coordinate system defining location and direction of damper
$R$
$h$
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