Edit Module

Managing Representations

A module representation is simply a way a module can be represented. Valid representation types can be assigned using the Type drop-down menu and include:

CAVITY: A finite element model that contains only fluid elements.
CMS: An H3D or OP2 based component modal synthesis model.
CDS: An H3D based component dynamic stiffness model.; An option to convert test FRFs in UNV format to CDS H3D and define it as module representation.
FE: Typical detailed finite element models.
DMIG: DMIG based model files in ASCII format.
FRF: A model containing frequency response functions.
LP: A lumped parameter model is a simplified 1D finite element model that represents dynamic behavior a more details model.
MODAL FE: A finite element modal model that contains spring/damper/spoint/mpc elements.
PLOT FE: A finite element model that contains PLOTEL, PLOTEL3 and PLOTEL4 elements.

Right-clicking the white space will give you the options to add, remove, or edit the description of the selected representation.

A file assigned to the root representation can be optionally auto-assigned to be a Display representation (PLOTFE type) simultaneously by checking the Assign file to Display representation checkbox.

A representation can be auto-selected to be the Display representation by checking the Set as Display, load and extract TagPoints checkbox. This will be followed by the file being imported into the 3D graphics window and TagPoints defined in the file extracted.

There is an option to specify tire module. If Tire module is activated, only two types of representations, MODAL FE and DMIG, can be assigned to the module. For Tire Module with type DMIG you can have CDtire with flexible rim or rigid rim. This is to handle the tire specific workflows of creating, editing CDTires, patch points management, positioning, and so on.

Once all representations are defined, click the Assembly Browser tab to review the assembly hierarchy with active Display and Analysis representations.

You can also specify Prep Folder for the module. This prep folder is a folder where you have read/write permissions to save the modified representation files.

Cavity Representation and Coupling Options

For representation type = Cavity, there are several options to handle its coupling with structural mesh and reduction. A Structural Module can be selected for fluid-structure coupling. Three types of coupling are available: ACMODL, AKUSMOD and DIMG. You can also specify SDAMPING.

Define Test FRFs (UNV) as module representations

An additional option in CDS-SE allows you to read UNV files that have test FRF information and convert them into a CDS-H3D file. This can then be assigned as module representation.

Modal model review and parameter modifications

These features allow for the review of modal model parameters of reduced model representations (both CMS-SE and Modal-FE) and modifying them. This will help you in understanding the effect of changing these parameters on NVH responses, without generating reduced models with necessary modifications.

The related list of features for CMS-SE are:

Validate SPOINT ids: Allows you to manage ID conflicts between SPOINT IDs of CMS-SE reduced model and module ID ranges.
Assign damping: Assign existing damping/add component damping to existing damping in CMS-SE. By default, existing damping while creating CMS-SE is used. There is also an option for adding damping to existing component damping.
Modal parameters review and modification: Use the ascii option to read modal parameters information from an .ascii file (_dmig_dv.inc) generated during the CMS-SE solver run. Information related to the modal is populated for review. Select Mode to modify the parameters. This will activate the Edit fields to modify frequency and damping values. There is also an option for the mode to be Grounded. Save and apply the changes. This modified information is then exported to the solver deck.
Animate Modes: Select a mode and click Preview Modes to visualize the mode shapes. The Modal Animation dialog opens to review mode shapes.

For Modal-FE, modal parameters are populated on loading the representation file. The options for review and modifications of parameters are the same as for CMS-SE. There is an option to save the representation file after saving the modified modal parameters. This new representation file is automatically assigned as a representation file to the respective module.

Managing Tagpoints

A Tagpoint is a special point used in the assembly for connection, input, response and plot purposes. It consists of a grid with a set of relevant properties, such as name, description and dependency.

Tagpoints are displayed in the 3D graphics area and can be customized via the NVH Module Display toolbar. By default, tagpoints are indicated with a gray sphere along with the label. Other options are available using the pull-down menu.

To add a tagpoint, right-click inside the tagpoint list in the Tagpoint tab and select Extract All to extract TagPoints from the comments added to the 10th field of the grids in the loaded Display model.

Lock ID: Lock ID’s provide you with a means to maintain the ID’s of tagpoints without getting renumbered by locking them. This prevents accidental renumbering of tagpoints.; Lock ID’s have a higher preference than the sub ranging utility. If ID’s are locked for tagpoints, then sub ranging will not renumber those locked ID’s in Prepare Module mode.; This utility can lock the ID’s of existing tagpoints using edit tagpoints or it can lock the tag ID while creating it using the Create TagPoints utility.

ID Tab

Sub ranging: Sub ranging provides you with a means to reserve a range so that it is not occupied and not referred by anybody. This is primarily needed if you want to reserve a certain ID range for a specific use and should not be occupied by other entities.; Some customers follow a convention of reserving the first 10,000 ID’s of nodes for connections for every include. They would like to reserve them at the start and then allocate these ID’s to the tagpoints pertaining to respective includes, by releasing the reserve range, when it is required.

The following images show a sample file with and without sub ranging.

Figure 4. Front Stab Bar without Sub Ranging

Figure 5. Front Stab Bar with Sub Ranging