Summary

In Finite Element Analysis (FEA), the efficient creation of bolt connections is crucial for ensuring the structural integrity and performance of mechanical assemblies. Bolts are integral in joining components, and their accurate modeling under load impacts the entire system. Fast and productive bolt modeling allows engineers to optimize designs quickly, meeting tight deadlines and enhancing overall productivity by freeing up resources for other critical design tasks. Additionally, precision in bolt modeling minimizes the risk of errors during model creation, which is essential for reliable and accurate analysis results. Therefore, creating bolt connections swiftly and without errors in FEA is vital for efficient, reliable, and successful engineering outcomes.

Discover how the 'Bolt Tools' Add-On helps you to generate Bolts in Ansys Mechanical to streamline your engineering projects, ensuring precision and efficiency in assembly simulations.

Step-by-Step Guide to Implementing 'Bolt Tools' Add-on

Example Geometry:

In this blog, a simple geometry is used to explain the automatic generation process. Two solid plates with the same holes array and face splitting to guide the mesh and bolt connections.

If your geometry has more than two plates the connections will be the same, just add the central parts and create the appropriate contacts and boundary conditions. Your bolts don't need to be connected to central parts in the majority of applications

Bolt creation:

To create a series of bolt connectors between solid bodies, is necessary to perform two steps in the 'Bolt tools' Add-on. For both of them, the 'Setup Wizard' will be the right tool:

1. Create the appropriate coordinate systems.

Open the 'Setup Wizard' from the 'Wizards' Menu.

In the right panel, choose the tab.

Select the geometry where you want to create bolts. Only one bolt end (head or thread) is necessary. In this example, the ring faces will work well for the bolt heads. Then click the 'Select' button on the 'Geometry' section.

To create the bolts, you'll need two coordinate systems placed at each bolt location. A cartesian and a cylindrical systems with the Z axis pointing in the axial bolt direction. Choose 'Cylindrical and Cartesian' option in 'Types to create'.

Additional options let you to manage names and grouping.

Finally, the 'Create Objects' button will create the new coordinate systems:

2. Generate the bolts.

Once the coordinate systems are created at each bolt location, you can use the tab to generate the connectors. The axial location of the coordinate systems is not definitive for bolt generation.

The first section of the tool is 'Coordinate Systems'. Here you'll select from the outline tree both (cartesian and cylindrical) for each bolt location. In this example, to create 16 bolts is necessary to select the 32 coordinate systems previously created, then click the 'Select Objects' button.

The next step is to specify both ends for each bolt. This task will be addressed using two outline tree objects: A Remote point and its defining nodal Named Selection. They will be created through the wizard, but understanding their logic, you'll be able to control the process. Now consider the following dimensions:

Click on the 'Define with form' button to open a new input window.

Let's imagine you're only creating the bolt placed at the same corner where the coordinate system is shown in the previous image. First, define the bolt head position:

Z location=0

Connection Z min and Z max= 0 and 1: Limits to select nodes on the surface normal direction (0 and 0 should work too).

Face Type= Planar: You're creating the bolt head.

Point Behavior Selection= Rigid or Deformable, depends on your modeling preference.

To add the first point, click the 'Go' button and a string will appear on the wizard.

Let's pause the creation for an instant and see how the corresponding nodal Named selection will be created. Note how the previously defined values are used to create the selection.

Now, we can continue with the other's end creation. Using the same definitions to the thread end. Here the coordinates are defined in the same system used for the first bolt end:

Z location=-80 (total separation of external surfaces)

Connection Radius=5.5: Slightly greater than the hole radius.

Connection Z min and Z max= -70 and -80: Limits to select nodes on the surface normal direction.

Face Type= Cylindrical: You're creating the bolt thread end.

Point Behavior Selection= Rigid or Deformable, depends on your modeling preference.

The Named Selection will be like this:

After clicking the 'Go' button you have a second portion on the Beam point string:

NOTE: Remember these Named selection will only be created at the end of the process, they are shown here to clarify the numeric parameter definition.

Two remote points will be created too. Note that the -80mm value in the Z-coordinate of the remote point definition has been created through the wizard in the 'Z Location' box.

Continuing with the wizard, the next step is to define the connector properties by the 'Define with Form' button:

Reference and mobile points: Previously defined ends, note 0 and -80 Z coordinates.

Name: Identifier.

Material: Select from project's available material list.

And finally you need to select an analysis if you want Probes to be automatically created.

To summarize, the wizard will look like this:

To finish the process, click the 'Create Objects Now'

The different object will look like this:

Now, you can define the boundary conditions and solve the analysis.

FINAL NOTE: You need to generate the mesh previous to use the wizard.

Exporting bolt reactions as a table