# Body: Flexible

Command ElementModifies a flexible body element.

## Format

<Body_Flexible
id                   = "integer"
label                = "string"
is_user_damp         = " { True | False } "
{
cdamp_expr           = "string"
|
usrsub_dll_name      = "string"
usrsub_param_string  = "string"
usrsub_fnc_name      = "string"
}
rigidified           = " { True | False } "
/> 

## Attributes

id
Element identification number (integer>0).
This is a number that is unique among all Body_Flexible elements.
is_user_damp
Changes how the damping coefficient for each mode is specified.
A value of "TRUE" indicates that the damping is specified using either an expression or a user defined subroutine.

A value of "FALSE" causes MotionSolve to ignore the damping expression or user-defined subroutine data provided in the Body_Flexible element and instead, use the damping values specified in the Reference_FlexData element.

cdamp_expr
Modifies the state dependent expression used to define the damping coefficient for each mode. Use this parameter only when is_user_damp = "TRUE". Any valid run-time MotionSolve expression can be provided as input.
usrsub_dll_name
Changes the path, name, or both for the shared library that contains your user subroutine. MotionSolve uses this information to load the user subroutine specified by usrsub_fnc_name in the library at run time. Use this keyword only whenis_user_damp = "TRUE".
usrsub_param_string
Changes the list of parameters that are passed from the data file to the user written subroutine. Use this keyword only when is_user_damp = "TRUE".
The syntax for this attribute is:
USER([[par_1],[par_2],...,[par_n]])
usrsub_fnc_name
Modifies the name of the user subroutine function specified in the model element.
rigidified
Converts the flexible body to a rigid body.
The default value for this flag is rigidified = "FALSE".

## Example

The following example illustrates the use of the <Body_Flexible> command element to modify the damping of a flexible body defined in the model:

<Body_Flexible
id                  = "30102"
cdamp_expr          = "IF(FXFREQ-100:1.0,1.0,1.0)"
/>