# Six Degrees of Freedom

## Introduction

A new type of Mechanical set has been implemented to able to take into account the Six degrees of freedom of a motion.

It is now possible to apply a rotating and/or translating movements to the moving mechanical set at each resolution step.

Three workflows are possible:
• Drive a "free" mechanical set with multiphysics parameters in order to co-simulate with Activate
• Drive a "free" mechanical set with multiphysics parameters by using Flux multiphysics context
• Drive a "free" mechanical set directly in Flux with parameters controlled by a scenario

## What's 6 degrees of freedom?

There are 6 possible motions, 3 translations and 3 rotations with independent directions:

In space, using an orthonormal coordinate system (O,x,y,z), the 6 degrees of freedom are defined as follows:

Degree of freedom 3D 2D
Translation along the X axis
Translation along the Y axis
Translation along the Z axis
Rotation around the X axis
Rotation around the Y axis
Rotation around the Z axis

## Create a 6 degrees of freedom mechanical set

1. Open the dialog box of the creation of a mechanical set:

Click on Physics > Mechanical Set > New

2. Choose the name of the Mechanical set

3. Choose Six degrees of freedom type

4. On Defintion tab, choose the Coordinate system

5. On Kinematics tab, choose the Multiphysic for the Type of kinematics
Note: There is no choice, the Multiphysic type is the only choice (no coupled load or imposed position/speed for this type of mechanical set)

6. Validate by clicking on OK

→ the mechanical set is created and displayed on the data tree

→ I/O parameters are automatically created ( six for a 3D project, and three for a 2D project)

Data Tree in a 2D project Data Tree in a 3D project
→ By default the parameters associated to the "6 degrees of freedom" Mechanical Set are multiphysic parameters. These parameters can be directly used:
• in a coupling with an other software like Activate.
• in the multiphysic context of Flux

→ If you want to use a 6 degrees of freedom mechanical set directly in Flux, you should edit the parameter and change type from Parameter for multiphysical application to Parameter controlled by a scenario

## Workflow: multiphysics parameters used by Activate

1. Create the mechanical set with the type "6 degrees of freedom"
2. Assign the mechanical set to the wished regions
3. Generate a Flux-Activate component, by clicking on Solving > Generate component for Activate coupling
4. Go to Activate to pilot the co-simulation

## Workflow: multiphysics parameter used by Flux multiphysics context

1. Create the mechanical set with the type "6 degrees of freedom"
2. Assign the mechanical set to the wished regions
3. Open a Flux multiphysics context by right clicking on a scenario (previously created) and choosing Multi physic solving session (existing scenario)
4. Go to the next step by clicking on Multiphysics solving > Activate the next step
5. Update the value of multiphysics parameters by clicking on Parameter/Quantity > I/O Parameter > Update current value of a multiphysics I/O parameter
6. Solve the step by clicking on Multiphysics solving > Solve the current step
7. Replay 4 - 5 - 6 if you want other steps
Note: these steps can be done by python with a loop to solve automatically the list of steps which you want
8. Close the multiphysics context
9. Post-process

## Workflow: parameter controlled by a scenario

1. Create the mechanical set with the type "6 degrees of freedom"
2. Assign the mechanical set to the wished regions
3. Edit predefined parameters
4. Change the type from Parameter for multiphysical application to Parameter controlled by a scenario
5. Create a scenario and use these parameters to pilot the scenario
6. Solve
7. Post-process