Bolt universal connections

You can use the universal bolt connection command to create and manage all of the bolts within your model.

You can create large quantities of bolts within a single connection. Additionally, you can automatically set the diameter of each bolt by using the Flange Hole Detection option to detect hole diameters when one or more of the clamping surfaces consist of 2D meshes or polygon faces.

Bolt connection prior to meshing

Like other universal connections, bolt connections are solver independent. You can use them across multiple solvers, including Nastran, Abaqus, and ANSYS.

You can import and export universal bolt connections within your model using Import Connections and Export Connections commands respectively.

For more information about importing universal connections, see Importing and exporting weld connections with xMCF.

For more information about exporting universal connections, see Export universal connections using xMCF.

Define clamping surfaces

When creating a bolt connection, you must define the target flanges that will act as the clamping surfaces of the connection. You can do this by selecting meshes, polygon bodies, polygon faces, or selection recipes.

If you want to quickly add multiple bolts, you can drag a selection box around your entire model to select all surfaces.

Locations

After defining the target flanges, you must specify the location and orientation of the bolt axis.

When you add a location, the Locations List displays information for each location entity such as the Axis Setup type. The shank diameter, head diameter, and connection length are also displayed in the list upon creating the connection and reopening the dialog box.

If you plan to	Use this axis setup type
Quickly and conveniently create bolts. You can create bolts by selecting two mesh points, nodes, or points to define the axis of each bolt.However, locations defined using mesh points and nodes are deleted when remeshing part geometry, which can cause the connection to fail.If you plan to frequently remesh part geometry, consider using Set of Curves or Selection Recipes, as the selection recipes update after remeshing.	Points
Frequently adjust the distance between flanges, as it allows the bolt length to vary as you change the distance. You can create bolts by selecting a mesh point, node, or point to define the start location of the bolt and a vector to represent the direction in which the connection will be generated.	Vector
Create and edit larger quantities of bolts. You can do so by selecting a selection recipe that contains curves, which represent centerlines at the bolt locations.	Set of Curves
Frequently remesh part geometry. You can create bolts by providing two selection recipes, each containing a single point, mesh point, or node to define the axis of each bolt.Since the X,Y, and Z coordinates of each point are stored in a selection recipe, the connection is able to update and resolve to a node when you remesh part geometry.	Selection Recipes

Physical properties

You can define the physical properties and characteristics of the realized (meshed) bolt connection elements, such as:

• Shank diameter

• Head diameter

• Override shank length

• Maximum connection length

• Material properties

You can set the shank diameter automatically based on the detected hole diameters of the target flanges by setting Head Diameter is Defined by to Flange Hole Detection.

After setting the shank diameter automatically, you can allow each bolt to have a different head diameter based on its detected shank diameter by setting Head Diameter is Defined by to Factor of Shank Diameter.

Bolt connection elements

After creating a universal connection, you must create the connection elements (that is, realize or mesh the connections) before solving the model.

The following table shows the valid combinations of elements when realizing (meshing) a bolt connection.

To model bolts	Select this element type	Realized (meshed) connection
Elastically, which allows you to analyze tension, compression, torsion, bending and shear within the bolts.	CBAR+RBE2 spider(s) (Nastran)CBEAM+RBE2 spider(s) (Nastran)B31+CONNECTORS spider(s) (Abaqus)BEAM188+CERIG spider(s) (ANSYS)The beam elements are connected to the flanges through spider elements. If the spider elements connect to a flange containing 2D elements, all the DOFs are fixed. If the spider elements connect to a flange containing 3D elements, only the translational DOFs are fixed.
Rigidly, which allows you to reduce both model complexity and computational time.	RBE2 Spider (Nastran)CONNECTORS (Abaqus)The selected flanges are connected via a spider element. If the spider element connects to a flange containing 2D elements, all the DOFs are fixed. If the spider element connects to a flange containing 3D elements, only the translational DOFs are fixed.Note: Available only in the Nastran and Abaqus solver environments.

If you choose to model the bolt elastically using CBAR+RBE2 spider(s), CBEAM+RBE2 spider(s), B31+CONNECTORS spider(s), or BEAM188+CERIG spider(s), you can provide further control over the creation of the beam element such as overriding the shank diameter, setting the minimum shank element length, and splitting the shank element. For more information on these features, see Connection element dialog boxes.

After splitting the shank element in the ANSYS solver environment, you can create a pretension section between the elements to simulate the effects of bolt preload. For more information, see Simulate a bolt preload in ANSYS using universal bolt connections.

Where do I find it?

Application	Pre/Post
Prerequisite	A FEM or assembly FEM file as the work part and displayed part
Command Finder	Universal Bolt Connection Connection Elements Automatic Connection Elements

Bolt universal connection customer defaults

Menu	File→Utilities→Customer Defaults
Location in dialog box	Simulation→Pre/Post→Universal Connections→ Bolt tab

How do I

Simulate a bolt preload in ANSYS using universal bolt connections

Create large quantities of bolts in one connection

Learn more

Override the length of bolt shanks

Extending the legs of spider elements in bolt connections

Bolt universal connections in the Nastran environment

Bolt universal connections in the LS-DYNA environment

Meshing LS-DYNA bolt connections with rigid body elements

Meshing LS-DYNA bolt connections rigid body and beam elements

Quick links

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

Browse Simcenter 3D help by product area

Bolt universal connections, Simcenter 3D 2021.1 Series

© 2020 Siemens

window.mainLanguage="en_US"

window.delivId=""

window.projectId=""

MathJax.Hub.Config({ TeX: { extensions: ["autoload-all.js"] }, tex2jax: { displayMath: [ ] }, "SVG": { scale: 125 } });