Frequency response analysis#

Qualitative measure of a system or device in response to a stimulus used to characterize the dynamics of a system. Dynamic characterization of the transfer function response of the composition in frequency domain.

Axis positions#

Define the position of the axis. Default is (0,0,0).

Loads#

Open the load case container, where load cases can be defined (CTRL+K on load case to configure).

Configure selected load#

Define and configure the load case here.

Force/Moment#

Define the direction of the force/moment. By entering 1 in a corresponding direction means that a force/moment is applied in this direction scaled by 1.

Direction

Force/Moment

u

Force in axial direction

v

Force in transversal direction

w

Force in normal direction

ru

Torque around axial direction

rv

Moment around transversal direction

rw

Moment around normal direction

Add component acceleration#

Add a component acceleration load case. For example, an acceleration of -9,81 m/s2 in w-direction defines the gravitational force to the selected component.

Add composition acceleration#

Add a composition acceleration. The acceleration is used for the whole composition and not for a component only, as in add component acceleration. For example, an acceleration of -9,81 m/s2 in w-direction defines the gravitational force to the composition.

Add controller command#

Add a controller command load. Either a position or a velocity command value can be defined acting on the selected controller.

Add rail profile#

Add a rail profile to a moving interface. This load adds a displacement between master and slave interface depending on the position of the carriage along the rail. The profile displacments are handled in the same manner as with link spacers (internal conversion to force & moment preloads using link stiffnesses). The corresponding displacement degrees of freedom will be equal to the input values only when no external load is present.

Average over car length#

This option enables & disables the carriage length averaging. This affects the profile load’s normal translational displacement (in direction of the profile normal dir vector, see below) and the pitch rotational displacement (around the axis normal to the travel direction and profile normal dir). The behaviour is as follows:

Option

Normal Translation Displacement Input

Pitch Rotation Displacement Input

Off

taken directly from the profile value at the centre of the carriage

always zero (i.e., the resulting preload moment is also always zero)

On

averaged over the entire carriage length (using 20 sampling points)

derived using a profile trendline along the carriage length (using 20 sampling points)

Selected component and rail interface#

Select the component and the rail where the profile should be added.

Profile normal dir#

Define the normal direction of the rail profile.

Edit table#

Define rail profile using excel or the table directly.

Step

Action

1

Click on Table

2

Right-click into newely opened table and click on Copy header

3

Open Excel and paste the header in a new sheet

4

Define the time steps in the Time column

5

Define the values at every time step in the Value column

6

Copy the whole table including the header Time and Value

7

Right-click into the MORe-Table and click on Paste

8

Click on Plot to check if table was copied correctly

Additionally, the number in Number of rows can be changed. This allows to directly define the transient load data in the table.

Important: The headers of the table imported from Excel have to match the ones given in the MORe-Table. Furthermore, tables that have more than 1000 rows can not be copied into MORe.

Import data#

Import the rail profile from a .mat file.

Step

Action

1

Open matlab and define a vector of name or var which stores the time steps

2

Define a vector that stores the load data for every time step

3

Select both vectors and save them in a .mat file

4

Right-click on load_case_data and click on Import data

5

Select the .mat file

6

Click on Plot to check if table was copied correctly

Important: In the .mat file there has to be a vector called var, otherwise the import will not work.

Hint#

By right-clicking on the number in the first column, the load can be deleted.

Frequency range#

Define the frequency range for the frequency response analysis.

Number of points#

The number of points defines how many steps between the minimal and maximal frequency are taken.

Start calculation#

Start the calculation of the frequency response analysis.