RSG Dialog Builder in Abaqus/CAE – Generation of screws

Before creating the geometry, it is recommended to make a sketch of the screw and its parameters, see the picture below. This sketch can be further used in the PlugIn below. Likewise, a list of all parameters used should be created in advance. In the present example these are:

DK = head diameter
KH = head height
LS = shaft length
LG = thread length
DS = Shaft diameter
Pname = name of the part
Matname = name of the material
Secname = name of the section
Modules = Young’s Modulus
Dens = density of the material
NUE= Poisson’s ratio
msize = element size (% of DS)

Guide values: DK~1.5*DS ; KH~DS

Step 1 : Starting the macro recorder

As shown in the picture below, you start the Macro Manager via the Files tab. A new macro is generated there. It is recommended to save a new macro first only in the working directory (Work).

Step 2 : Create the screw geometry and partition the screw

When generating the geometry and datum levels, it is useful and helpful to use unique values, e.g. 7.777 for the parameter KH (head height of the screw). This way the value can be found quickly in the macro file and is then replaced by the corresponding parameter (see further down in the text). The part is called Bolt_Script. This name is freely selectable. Then a material and a section are defined. The section is assigned to the component.

Right picture shows the partitioned component with assigned Section, the 5 datum levels and the axis “Bolt_Axis”, which is not mandatory, but helpful for further scripts. Marked in red are further partitionings, which will be explained in more detail later.

Step 3 : Definition of the element type (here C3D8) and meshing of the screw with a global element size.

The element size is selected as 3,333. Thus, this value can be easily identified in the script and replaced by a parameter.

Step 4 : Close the macro recorder.

Now the file abaqusMacros.py can be opened with the editor. Here the editor Notepad++ ([5]) is used for editing and processing.

The macro is stored as a function (‘def’) in a Python script. The function does not yet contain any parameters and must now be filled. The import definitions are taken over, even if not all modules are needed. The name of the function may be changed.

Now the function is extended by the required parameters by entering the parameters as transfer values in the parenthesis behind the function name. This is where the previously created list proves helpful. The order is arbitrary, but the list must be complete.

DK = head diameter
KH = head height
LS = shaft length
LG = thread length
DS = Shaft diameter
Pname = name of the part
Matname = name of the material
Secname = name of the section
Modules = Young’s Modulus
Dens = density of the material
NUE= Poisson’s ratio
msize = element size (% of DS)

The placeholders VN and MN are generated. In the following, all entries of ‘Viewport: 1’ are replaced by VN and all entries of ‘Model-1’ are replaced by MN in the script. It is assumed that the part was created in Viewport 1 and the model was not renamed. Otherwise, the designations must be adjusted accordingly.

Now, in the script file, all the dimensions and names used in the creation of the part are replaced by their parameters. This shows that it was previously useful to provide the dimensions with recognizable values.

All 5 dimensions are replaced by the corresponding parameters (KH,DK,LS,LG,DS). The same applies to the datum planes created with an offset from the xy plane (see figure).

Finally the remaining parameters used in the script are assigned, here the part Bolt_Script is replaced by the parameter Pname ( The quotation marks of Bolt_Script may not be taken over ). If all parameters in the script are assigned, it is stored with the ending .py (Here: Bolt_without_Nut.py) and can be used now in the RSG-Builder. It is recommended to use a powerful editor up to this point, since the editor in the kernel module offers only limited functions.

Now the RSG Dialog Builder is opened and first a title is assigned

In the present example, it is useful to include the previously created sketch

Now 12 text fields are created for the 12 parameters
Text: Enter here the text that describes the parameter in more detail
Type: A distinction is made between string,
Float (numeric value) and Integer (integer value)
Keyword: Name of the parameter for the kernel
Default: Preset value

The finished GUI on the right in the image below.

Loading the script: Via the tab ‘Kernel’ and the icon for ‘Open file’ the script is loaded into the kernel of Abaqus/CAE. The script can also be edited further in this dialog.

The ‘Save file’ icon now saves the script under a name to be assigned, preferably in the working directory. If the script is to be loaded with every call, it is recommended to move the plugin from the working directory to the plugin directory of the installation afterwards.

For Windows versions this is e.g. : C:\Simulia\CAE\plugins23

Alternatively, a central plugin directory can be used. This is defined via plugin_central_dir in the environment file, see [4].

The PlugIn should only be stored in one directory, because Abaqus/CAE searches numerous locations for PlugIns and in case a PlugIn is found multiple times, a warning is issued when CAE is started. Saving it as an RSG PlugIn ensures that it can be subsequently edited and modified again.

In this example, the ‘Bolt_without_Nut’ directory for the plugin contains the following files: bolt_without_Nut_plugin.py, bolt_without_NutDB.py, bolt_without_nut.py and Simple_Bolt.png. We simply copy the entire directory to C:\Simulia\CAE\plugins23.

If we start Abaqus/CAE now, we can call the plugin (left in the picture below). Note that in the plugin the names for the new Part, a Material and a Section are agreed, in the image below center. A separate part name should be used for each screw. If the materials of different screws differ, new names should be defined for the material and the section. Otherwise, previous definitions will be overwritten without warning.

The screw is now ready created as well as meshed, right in the image below, and can now be imported into the assembly.

The created screw after calling the PlugIn. Shown in red are: Datum Axis Bolt_Axis , area BL_Surf for bolt force and area “Pname_+_Tie” for the connection of the threaded part with the corresponding component.

After successful creation of the PlugIn, valuable tools are available to the user:

• Quick creation of any number of different screws
• Easy application of screw preload over predefined area without interactive instance selection
• Easy selection of surfaces for connection with the components of the assembly

Especially for very large assemblies, such a plugin is indispensable.

Even if this post seems elaborate, creating a plugin with RSG Builder is, with a little practice, a powerful and simple way to efficiently reduce the effort required for recurring operations.

It is not guaranteed that the PlugIn always works across versions. This is because the partitions shown here in red were created with lines selected interactively. These lines appear in the script as a sequence of numbered lines whose numbering is not necessarily identical from version to version. The same applies to the inner surfaces for the bolt preload force and the surfaces of the threaded part.
This chapter presents a more general approach to scripting that should prevent such potential problems from occurring.

Partition of the screw head

Surfaces for bolt force

In the above procedure with the Macro Recorder, the lines (edges) are selected directly and the script uses the IDs of these edges, shown in the image below.

We replace this definition with a search for the 4 arcs needed for the partition. We benefit from the fact that we build up the screw ourselves within the part and thus the values are available for the search. The script block shown in the image below replaces the code from the macro recorder.

By using the Macro Recorder, IDs are used for the surfaces, see image below. These IDs could change.

We now use a script to find the 4 quarter circles needed for the bolt force. The following block replaces the code from the macro recorder.

The same applies to the surfaces for the connection to the component via a TIE constraint. We want to replace the getSequenceFromMask created by the Macro Recorder, see image below, with a more general formulation.

To define the faces independently of their numbering requires a few more steps to be added to the script in the kernel, as before, replacing the code from the macro recorder shown above. First, the following command selects all faces of the front partition.
Additional step #1

Selecting the faces on the two end faces, Additional Steps #2 and #3.

Selection of inner vertical and horizontal flats, Additional steps #4 and #5.

The created surfaces are now found in the tree of the part.

Additional step #6: Create Bolt_Tie area by Boolean operation: Subtract endsurf, intsurf, xsurf and ysurf areas from CYL_Surf area.
(Right mouse click on the selected Surfaces).
In the script Bolt_Tie becomes “Pname+Tie”.

Additional and last step #7: The now redundant surfaces are deleted

If you need many instances of one or different screws, the connection to the components can often be combined.

In this example, the screw has the name “M24x60”. The surfaces for the connection from the threaded surface of the screw to the part, with standardized name “Pname+_Tie”, can now be easily combined into a single surface without the need to select the instances. In “Create Display Group” use the filter to select these surfaces (*-filter is helpful) and save individual surfaces, e.g. “M24x60_Tie_Secondary”.

It is now just as easy to apply the bolt load without having to select the instance.
To do this, just select the surface “‘Pname’+BL_Surf” and apply the force or displacement (depending on the method). By activating ” Pre-tension section at part level” the force is applied to ALL screws.
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[1] Type Hints for Abaqus/Python Scripting(formerly Hailin Wang)

[2] Abaqus Scripting Users Guide in the DS User Manuals

[3] Abaqus Scripting Reference Guide in the DS User Manuals

[4] Abaqus/CAE Central Plugin Directory in the DS User Manuals

[5] Notepad++ website

We will be happy to provide you with the plugin. We also have a variant with mother. Unfortunately, we cannot provide a download link yet. Please use the contact option below. A request does not commit you to anything, just as we cannot take responsibility for the use of the plugin.

Bolt_without_Nut (bolt without nut, as described above) (download link/authorization required)

Bolt_with_Nut Bolt with nut
(download link/ /authorization required)