2.4 DIRAC v3.2

DIRAC v3.2.2

4 February 2022

Changes:

• Changes have been made to the way the impact and response spectrum is shown in Measure. The doubling of frequency lines above 0 Hz is now omitted. This way, the 0 Hz value is better in-line with the spectral amplitudes of the other frequency lines. This has no impact on any FRF data, just on how the frequency spectra are shown in Measure.

Fixes:

• Upgrades to the License Manager. This now keeps the settings centrally in the folder %localappdata%\VIBES.technology\Licensing, and shares these with other VIBES software. Upon the first start, you may need to reload the license server settings once.

DIRAC v3.2.1

20 December 2021

This version of DIRAC brings the following 3 main features. A video showing all the new functionalities can be found here.

Matrix post-processing options in Analyze
Matrix post-processing options have been added to the Analyze module. These options serve to perform additional calculations on the selected subset of the FRF matrix, specified as matrix presets. The options apply to so-called Custom Matrix Presets, as can be defined using the controls in the top-left corner. Options are available for:

• Converting the measured accelerance to another representation, such as receptance or dynamic stiffness. As a result, time-integration and matrix inversion is applied depending on the chosen representation. Note that only kinematic quantities such as Acceleration (m/s^2) and Rotational Acceleration (rad/s^2) are time-integrated; other quantities such as Sound Pressure (Pa) are unaffected.
• Transposing the matrix to obtain the reciprocal representation. This can be useful to get a reciprocal matrix, where the excitation positions become response positions and vise versa. The resulting quantities and units can be observed in the information panel.
• Element-wise inversion, as an alternative to the default option which uses full matrix inversion.

The panel to the right shows the effective post-processing steps to clarify what is processed, and which quantities are resulted as channels (rows) and reference channels (columns). The processing steps are applied to the FRF subset specified by the channel and reference channel selection for this particular matrix preset.

The post-processing options serve various purposes. A typical use case with direct engineering value is the calculation of Dynamic Stiffness of the Virtual Point transformed FRF Matrix. This can for instance be used for (rubber) mount characterization: the cross-diagonal reveals the dynamic stiffness in all 6 translational and rotational directions. It is further recommended to activate the Reciprocity matrix quality type in this case to assess the quality of the results.

As this type of post-processing is a common choice, a direct preset VP Dynamic Stiffness has been made available under the matrix preset dropdown menu. This preset will always apply to the Virtual Point FRF Matrix.

Undo and redo functionality in Prepare
Actions in the Prepare module can now be reversed and/or redone. When working on a design of experiment, actions such as positioning the sensors, aligning the Virtual Points or setting the impacts can be undone and redone in a user-friendly manner. Undo and redo actions are available in the renewed title bar as two buttons; the on-hover tooltip reveals the action that can be undone/redone. One may also use the key commands CTRL-Z and CTRL-Y.

The Undo/redo features include the following:

• Moving/rotating any object in the 3D viewer
• Changing properties in the Property widget
• Changing properties in List Mode
• Adding objects
• Removing objects
• Editing multiple objects at once

Improved UFF export
The option to export FRF matrices in UFF format has been extended. This feature works in a similar manner to the other exporters in DIRAC. Any sensor names that are longer than 10 characters will have their names shortened using the following logic:

• For excitations, the word “Excitation” will be replaced with “Exc”. For example, “Excitation 11” to “Exc 11”
• Channel names (Response Entity Name or Reference Entity Name) which are longer than 10 characters will be converted to Pascal Case where the spaces are removed and only the first letter of each word is capitalized. For example, “VP1 Force X” will be converted to “Vp1ForceX”
• Channel names that are still too long in Pascal Case, will be shortened to 10 characters and the Channel-ID will be added to the end to guarantee uniqueness. e.g. “EPS CP1 Right” will be converted to “EpsCp1Ri#7”

Other changes
Multiple objects can be moved as a group. If the selection contains impacts or mountable sensors, only XYZ translations are allowed.

• When attempting to delete sensors or impacts that are used in the campaign, a warning is issued. When continuing, the channel mappings and/or measurement data are removed and cannot be restored using undo.
• The main user interface has been revamped with a DIRAC-specific blue color. The new title bar provides quick action buttons for opening and saving the project, as well as the undo and redo actions in Prepare.
• The default color for excitations (impacts) has been changed to blue.
• Several smaller bug fixes for working in the Prepare module.