# Mforce

Model ElementMforce defines a distributed force on a flexible body (CMS) in MotionSolve.

Mforce

## Description

Mforce can be implemented three ways:
• The force shape is scaled by a function expression.
• The force shape is scaled in a compiled user-subroutine.
• The force shape is scaled in an scripted user-subroutine.

## Attribute Summary

Name Property Modifiable by command? Designable?
id Int ()   No
label Str () Yes
case_index Int () Yes
scale Function () Yes
flex_body Reference (FlexBody) Yes
function Function ("MFOSUB") Yes
force Function () Yes
routine Routine ()
active Bool () Yes

## Usage

#1: Scale factor defined in an expression for scaling a modal force shape
Mforce (flex_body=objFlexBody, case_index=int, scale=double, optional_attributes)

#2: Scale factor or modal force defined in an compiled user-written subroutine
Mforce (flex_body=objFlexBody, function=userString, routine=string optional_attributes)

#3: Scale factor defined in a Python functionMforce (flex_body=objFlexBody, function=userString, routine=functionPointer, optional_attributes)

## Attributes

flex_body
Reference to a Flex_Body.
Defines the ID of a flex body on which the modal load is applied.
The flex_body attribute is mandatory.
case_index
Integer
Specifies the modal load case number that is used to define the shape of the distributed load.
The case_index attribute is mandatory.
scale
Double
Specifies an expression for the scale factor to be applied to the load case referenced by case_index.
The scale attribute is mandatory.
The force shape is scaled in a compiled user-subroutine
flex_body
Reference to a Flex_Body.
Defines the ID of a flex body on which the modal load is applied.
The flex_body attribute is mandatory.
function
String
The list of parameters that are passed from the data file to the user-defined subroutine.
The function attribute is mandatory.
routine
String
Specifies an alternative name for the user subroutine. The name consists of two pieces of information, separated by "::". The first is the pathname to the shared library containing the function that computes the response of the user-defined Field. The second is the name of the function in the shared library that does the computation.
An example is: routine="/staff/altair/myfield.dll::mymfosub".
• "/staff/altair/mymfosub.dll is the DLL
• "mymfosub" is the function within this DLL that performs the calculations
The routine attribute is optional. When not specified, it defaults to MFOSUB.
force
String
Specifies whether the user subroutine returns a shape that is to be scaled or the actual modal force itself. Set this to "USER" to specify that the MFOSUB returns the actual force.
The force attribute is optional. When it is not specified, MotionSolve will assume that the user-subroutine computes a scale factor, not a modal force.
The force shape is scaled in a scripted user-subroutine
flex_body
Reference to a Flex_Body.
Defines the ID of a flex body on which the modal load is applied.
The flex_body attribute is mandatory.
function
String defining a valid user function MotionSolve expression.
The list of parameters that are passed from the data file to the user defined subroutine where the Variable is defined.
The function attribute is mandatory.
routine
Pointer to a callable function in Python.
• myModalLoad is a Python function or method that can be called from wherever the model resides.
The attribute routine is optional.
When not specified, routine defaults to MFOSUB.
force
String
Specifies whether the user subroutine returns a shape that is to be scaled or the actual force itself. Set this to "USER" to specify that the MFOSUB returns the actual force.
The force attribute is optional. When it is not specified, MotionSolve will assume that the user-subroutine computes a scale factor, not a modal force.
Optional attributes - Available to all variants
id
Integer
Specifies the element identification number. This number must be unique among all the Mforce objects in the model.
This attribute is optional. MotionSolve will automatically create an ID when one is not specified.
Range of values: id > 0
label
String
Specifies the name of the Mforce object.
This attribute is optional. When not specified, MotionSolve will create a label for you.
active
Bool
Select one from True or False.
• True indicates that the element is active in the model and it affects the behavior of the system
• False indicates that the element is inactive in the model and it does not affect the behavior of the system. It is almost as if the entity was removed from the model, of course with the exception that can be turned "ON" when desirable.
The attribute active is optional. When not specified, active defaults to True.

## Example

The example below shows a definition of a Mforce.
disturbanceLoad = Mforce (label="Disturbance", flex_body=wing, case_index=1, scale="1.0 + 0.2*sin(360d*time) + 0.1*sin(360d*time*3)")