Lumped Mass dialog box

General page

Mass Type
On Nodes	Lets you define the connection directly on the nodes. You can select the nodes from the model, meshes, or selection recipes.Note: This option is not supported for lumped mass connections that you want to import into NVH Composer. For more information, see Mass List view.
With Spiders	Lets you define a position in space for the mass, and the locations of the legs that connect the mass to the model.
Distribution Type
Appears when Mass Type is set to On Nodes.
Distributed	Divides the total mass by the number of selected nodes.
Repeated	Adds the total mass to each selected node.
Name
Name	Sets the name of the lumped mass. After you create the first lumped mass, the software numbers them sequentially starting with 1. You can either use this default name or provide a new name.
Description	Sets a description for the lumped mass.To manage the text, you can use the Cut , Copy , and Paste commands. This description appears in the Description column in the Simulation Navigator.
Folder
Specifies the folder in the Universal Connections container where you want to save the connection. Using folders helps you to effectively manage a large number of connections.
Select Folder	Opens the Folder Selector dialog box, which lists the folders in the Universal Connections container. You can specify the destination folder for your connection from here.

Targets page

Target Nodal Selection
Appears when Mass Type is set to On Nodes.
Select Objects	Lets you select any of the following entities:Elements, element edges, element facesMeshMesh point or nodePolygon face, polygon bodySelection recipeThe software returns all of the nodes that are associated with the selected entities. The lumped mass is created on those nodes.
Nodal location table	Lists each entity that you add. To delete a location, click a row and click Delete .
The following options appear when Mass Type is set to With Spiders.
Center
Use Mean Coordinates of Leg Locations	Lets the software determine the center. When you clear this check box, you can manually set the center by selecting an object, creating a point, or selecting a node using its label.Spider center computed automatically****Spider center selected manuallyNote: This option is not supported for lumped mass connections that you want to import into NVH Composer. For more information, see Mass List view.	Spider center computed automatically	Spider center selected manually
Spider center computed automatically	Spider center selected manually
Select Object	Appears when the Use Mean Coordinates of Leg Locations check box is cleared.Lets you select the center. You can select a mesh point, node, point, or selection recipe that resolves to one of those entities.
Create New Point	Opens the Point dialog box where you can create a new point for the center.
Labels	Type a node label and click to select it as the center.
Leg Locations
Sets the location of the spider legs with any combination of geometric (point, edge, face, body) or finite element (node, edge, face, element, mesh) objects that can return the nodes to use in the legs.
Select Object	Select the nodes or points to identify the legs that connect to the lumped mass. You can select mesh points, nodes, points, or a selection recipe that returns those entities.When you use a selection recipe, the selection recipe is identified in the table with a single ID, and the legs are created as follows:If the selection recipe does not explicitly include nodes or points, but it does include entities such as polygon edge, mesh, and so on, the connection uses the nodes or points associated with those entities to create the legs.If the selection recipe explicitly includes nodes or points for leg locations, the connection uses those nodes or points to create the legs.In both cases, the legs are identified as subindexes of the selection recipe. For example, if the selection recipe is labeled in the table with ID 1, and the selection recipe contains entities that create three legs, the legs are numbered 1.1, 1.2, and 1.3 in the graphics window. This allows you to quickly locate the source of the legs.
Create New Point	Opens the Point dialog box. You can create a new point for each leg.
Leg location table list	Lists each location that you add. To delete a location, click a row and click Delete .
Connection Target
Select Objects	Lets you select the part of the model that the legs and lumped mass will connect to.
Target Detection
Max. Search Distance	Sets the maximum distance you want the software to search from the leg node or point to the connection target.
Connect Legs To
Nearest Node	Finds the nearest node to the leg location within the distance specified by Max. Search Distance.
Local Spiders	Connects the main spider legs to a hole or nodes using local spiders.****Note: If the leg is located on the surface of the hole, the software creates a planar local spider.
The following options appear when Connect Legs To is set to Local Spiders.
Connect Spiders To
Nearest Selected Target	Connects the local spider to the closest target from the Connection Target objects you selected.
All Selected Targets	Connects the local spider to all of the targets from the Connection Target objects you selected that are in the range you specify Target Search Range.
Target Search Range	Appears when you select All Selected Targets.Sets the range within which you want the software to search for all of the targets. If a Connection Target lies outside of this range, the spider is not connected to it.
Ring Options
1 Ring	Connects the legs of the local spider to the nodes of the free edges of the hole. The center of the local spider is computed as the center of gravity of the nodes of the legs.Single ringIf a hole is not detected, no local spider is generated, and the leg connects to the closest node.
2 Rings	Connects the legs of the local spider to the nodes of the free edges of the hole and to the nodes of the first layer of elements around the hole. The center of the local spider is computed as the center of gravity of the nodes of the legs.Concentric ringsIf a hole is not detected, no local spider is generated, and the leg connects to the closest node.
Expansion Radius	Lets you enter a search radius. The software searches for all nodes within the radius you specify. If the radius is smaller than the distance set by Max. Search Distance, a local spider is created on the first ring.If the legs are defined on parts without holes, the software creates a spider and moves the leg to the computed center of the spider.****
Expansion Radius Factor	Lets you enter a search radius factor to determine the size of the range that can be searched. The software searches for all nodes within the range determined by multiplying the expansion radius factor with the distance between the center and the node that is closest to the center. This is determined as follows:R = D * Fwhere:R is the search range.D is the average of all of the distances between the center of the hole and the node that is closest to the centerF is the value you enter for Expansion Radius FactorNote: If no hole is detected, the legs are attached to the closest node within the range.

Physicals page

Mass
Mass	For a lumped mass that is defined by nodes, sets the mass that is repeated on each node or distributed across all of the nodes, depending on how Mass Type is set.For a lumped mass that is defined with spiders, sets the mass that is positioned in space.
Axis Type
Appears when Mass Type is set to On Nodes with Distribution Type set to Repeated, or when Mass Type is set to With Spiders.Specifies the axis for the lumped mass Mass Moment of Inertia and Mass Product of Inertia values.
Absolute	Sets the coordinate system to the absolute coordinate system.
CartesianCylindricalSpherical	Lets you specify a coordinate system.
Specify CSYS	Appears when the axis type is set to Cartesian, Cylindrical, or Spherical.Click CSYS Dialog to open the CSYS dialog box where you can define the coordinate system. For more information, see CSYS dialog box.To create a coordinate system, select a command from the list.
Mass Moment of Inertia
IxxIyyIzz	Sets the moment of inertia.Inertia 11 = IXXInertia 22 = IYYInertia 33 = IZZ
Mass Product of Inertia
IyxIzxIzy	Sets the product of inertia.Inertia 21 = IYXInertia 31 = IZXInertia 32 = IZY

Additional magnitude options for boundary conditions
You can define the magnitude with a constant value, expression, or field. You can:Type a constant value directly in the box.Type an expression directly in the box. As you begin to type the expression, tooltips provide hints about valid parameter names. If you type an invalid or incomplete expression, the warning icon appears next to the box.Click and select:
Expression	Opens the Expressions dialog box, where you can select an existing expression or create a new one.For more information about expressions, see Expressions.
For more information about other options in the list, see Additional magnitude options.

How do I

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Lumped Mass dialog box, Simcenter 3D 2021.1 Series

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