# Metafor

ULiege - Aerospace & Mechanical Engineering

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doc:user:elements:specials:damping

# Damping

## Materials

A damping is defined is the same way as volume materials:

materialno = materialset.define (number, type)
materialno = materialset(number)
materialno.put(param, value)
materialno.depend(param, fct, Key(Lock)))
...
 number damping number (must be unique for all element in materialset, not just for dampings) type type of damping(for example DampingMaterial) param name of the damping parameter (for example SPRING_FC) value value of the corresponding parameter fct function which characterizes the dependency of the property (optional: no fct if no dependency) Lock Lock which defines the dependency variable of the property (compulsory if there is a dependency)

### DampingMaterial

Damping material

#### Parameters

Name Metafor Code Dependency
Damping coefficient SPRING_FC -

## Element

Once the material is defined, it must be associated to an ElementProperties:

prp = ElementProperties(typeEl)
prp.put(param1, value1)
prp.depend(param1, fct1, Lock1)) #facultatif
prp.put(param2, value2)
prp.depend(param2, fct2, Lock2)  # facultatif
...

where

 typeEl desired element (for example Damping[2|3]DElement for dampings) param1, param2 name of the property associated to the element (for example MATERIAL to associate the desired material) value1, value2 value of the corresponding property fct1, fct2 function which characterizes the dependency of the property (optional: no fct if no dependency) Lock1, Lock2 Lock which defines the dependency variable of the property (compulsory if there is a dependency)

### Damping[2|3]DElement

Damping element. No axisymmetric correction is implemented. They must be associated with a FieldApplicator interaction.

#### Parameters

Name Metafor Code Dependency
MATERIAL Number of the damping material to consider -
STIFFMETHOD Method used to compute the stiffness matrix
= STIFF_ANALYTIC : analytic matrix (default)\\= STIFF_NUMERIC : numerical matrix
-

## Interaction

Finally, once the Mass[2|3]DElement ElementProperties is defined, the corresponding interaction is generated with the FieldApplicator. To do so, the corresponding geometric mesh element must be generated using 0D Meshers (Points). Once done, the interaction can be defined and included in the interactionset:

app = FieldApplicator(no)
app.push(gObject1)
app.push(gObject2)
...
app.addProperty(prp)        # association of an ElementProperties
interactionset.add(app)     # the interaction is added in InteractionSet 

or

app = interactionset.add(FieldApplicator(no)) #add returns a reference
app.push(gObject1)
app.push(gObject2)
...
app.addProperty(prp)        # association of an ElementProperties

where

 no number of the Interaction (which is to say the FieldApplicator) gObject1, gObject2 meshed geometric entity where the finite elements are applied prp Properties of Elements to generate.
doc/user/elements/specials/damping.txt · Last modified: 2016/03/30 15:23 (external edit)