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 # Flexible Body

 Last update: 17.07.2025 

A Flexible Body is used by RBD for bodies that have flexible behavior, for instance a [CMSBody](cmsbody.md).

### Constructors

None.

### Members

`AlphaDamping`

Uses a variable to define the amount of alpha Rayleigh damping (proportional to the mass matrix) to be considered for the flexible body. The variable can be either dependent or constant.

Example:

```
aFlexibleBody.AlphaDamping=100

```

Or equivalently:

```
var=CS_Variable()
var.SetConstantValues(System.Array[float]([100.]))
aFlexibleBody.AlphaDamping=var

```

`BetaDamping`

Uses a variable to define the amount of beta Rayleigh damping (proportional to the mass matrix) to be considered for the flexible body. The variable can be either dependent or constant.

Example:

```
Env=CS_Environment.GetDefault()
Sys=Env.System
 
array=System.Array.CreateInstance(float,4,2)
array[0,0]=0.0
array[0,1]=5.e-6
array[1,0]=0.05
array[1,1]=5.e-6
array[2,0]=0.051
array[2,1]=1.e-4
array[3,0]=0.1
array[3,1]=1.e-4
 
table=CS_PointsTable(array)
 
(err,found,time)=Sys.FindOrCreateInternalMeasure(CS_Measure.E_MeasureType.E_Time)
 
var=CS_Variable()
var.AddInputMeasure(time)
var.SetTable(table)
 
aFlexibleBody.BetaDamping = var

```

`CMatrixScaleFactor`

Define a factor to be used to multiply the default damping matrix. For instance, with a [CMSBody](cmsbody.md), this matrix can be created during the generation pass. When the damping matrix is generated for a Condensed Part ([CMSBody](cmsbody.md)), it will be automatically taken into account in the RBD use pass with a factor equal to 1.0.

### Member functions

`SetModalDamping(iDof, variable)`

Define the amount of damping used for the degree of freedom specified by `iDof` (index starts at 0). The variable can be either dependent or constant.

`GetModalDamping(iDof)`

Retrieve the damping variable defined for the degree of freedom `iDof` (index starts at 0).

`SetLoadVectorScaleFactor(iLV, variable)`

Define a scale factor applied to the flexible body internal load specified by `iLV` (index starts at 0). By default, the first load vector uses a constant scale factor equal to 1.0.

`GetLoadVectorScaleFactor(iLV, variable)`

Retrieve the variable associated to the factor specified by `iLV` (index starts at 0).

### Derived classes

`CS_CMSBody`