|Connectors:||Mechanical Connector (linear)||ctr1||connectable to elements of the Linear Mechanics library|
|Mechanical Connector (linear)||ctr2||connectable to elements of the Linear Mechanics library|
|Parameters:||Damping||b||not visible, if rigid==true|
|Rigid||rigid||if true, the element behaves as rigid|
|Initial Preload of Damper||kindPD||
|Initial Velocity Difference||dv0||only visible if kindPD=="Preload Velocity Difference"|
|Initial Damping Force||Fd0||only visible if kindPD=="Preload Force"|
|Power Loss||Pl||not visible, if rigid==true|
|External Power||Pe||only visible, if rigid==true|
This Damper model represents a linear (translational) damper. Thus it allows to realize absolute as well as relative viscous (i.e., speed-proportional) dampings.
- The damper is parameterized by the damping ("constant") b.
- If rigid is true, the element behaves as rigid, which means, it behaves as a Constraint with dx==0. In this case, the damping b is deactivated.
This group contains the enumeration kindPD and (depending on the setting of kindPD) dv0 and Fd0 for the preload of the damper.
- The enumeration kindPD holds a selection of initial states of the damper:
- "No Preload or Preload from Environment": This is the default selection. The damper is initially unloaded or will be pre-loaded by the environmental conditions (i.e. initial values at the connections at ctr1 or ctr2).
- "Preload Velocity Difference": The damper is pre-loaded. This option activates the parameter dv0, the initial velocity difference.
- "Preload Force": The damper is pre-loaded. This option activates the parameter Fd0, the pre-load force.
- dv0 ... initial velocity difference of the damper
- The value of this parameter must be consistent with the initial values of the connections at ctr1 (-> v10) and ctr2 (-> v20):
dv0 == v10 - v20
To fulfill this constraint, it is recommend to unfixv10 or v20 (-> the corresponding initial values of the connections).
- Fd0 ... the initial damping force or pre-load
- Here, dv0 will be computed internally by dv0 = Fd0/b taking the damping b into account.
- Note: Also here the initial values of the velocities must be consistent (see above).
- The Internal Force of
the damper results from the damping b and the speed difference as
- The Displacement Difference
is the difference between the current displacements of the connections, which are linked
to the connectors ctr1 and ctr2:
= ctr1.x - ctr2.x
- The Velocity Difference results
from the velocities at the connectors respectively:
= ctr1.v - ctr2.v
- The Power Loss is computed as:
- If rigid == true,
the external power Pe is computed:
If this power is positive, the element acts as a power source, otherwise it consumes power.
For modeling relative dampings the element is placed between two linear components. For an absolute damping one of the connectors is connected to a fixation (using the element type Preset), or remains unconnected (this is equivalent to a fixation).