Included with SOLIDWORKS 2022 is a new kind of connector called a linkage rod. The linkage rod is a convenient way to connect components in your assembly without having to model physical geometry. Linkage rod connectors are available in SOLIDWORKS Simulation Professional and Premium.
To access this functionality, right click on your “Connections” folder in the Simulation study tree and then select “Linkage Rod”.
At the top of the Property Manager are selection boxes for specifying geometry at each of the two ends of a linkage rod. You can choose cylindrical faces, shell edges or vertices.
In the blue boxes shown above, the user can specify an offset distance to position the ends of the connector. You can only select cylindrical faces or circular edges to define the offset distance.
In the red boxes shown above are three options available for specifying the “fixity” of each joint. The first option is a rigid joint, which prevents any rotations or deformations. In other words, a rigid joint can transfer all moments from one part to the other. The second option is a pivot joint. A pivot joint will only allow rotation about the axis normal to the connector’s axis. The third option is a spherical joint. Much like a ball and socket, this joint allows free rotation but no translation.
If you scroll to the bottom of the Linkage Rod Property Manager, you will find options for specifying the cross section of the connector.
Clicking the drop-down menu below “Section Parameters” gives the following choices.
Choose the cross-sectional shape of your linkage rod and enter the appropriate geometric information.
The last section of the property manager is where the user applies a material to the connector, either from the SOLIDWORKS material library or a custom material.
To demonstrate some of the functionality, I created a simple model consisting of two tillers joined by a connecting rod. A tiller is a lever arm used in steering mechanisms. The linkage rod is shown in dark blue, the default color for “virtual” connectors in SOLIDWORKS Simulation.
The right tiller is free to rotate about its base. The left tiller is fixed at its base. There is a load applied in the X direction to the right tiller.
To explore the effect of joint end fixity, I created 3 examples using the different end conditions – rigid joints, pivot joints and spherical joints – at both ends of the linkage rod.
The displacement results are shown below:
The displacements are lower in the case of rigid joints because the additional fixity adds resistance to the movement of the tillers and link arms. The displacements are identical between pivot and spherical joints because the applied load is in the plane of the tillers, so these two joint types behave the same way for this load case.
We can interrogate the internal forces in the linkage rod by right clicking the results folder and then selecting “List result force” and then choosing “Connector force”.
As the table shows, the rigid joints induce a bending moment in the linkage rod, whereas the pivot and spherical joints have no bending moments.
To illustrate the difference between pivot joints and spherical joints, I added an out of plane load to the right tiller.
As we see in the displacement plot below, the pivot joints and spherical joints now behave quite differently. We get 10.36mm of maximum displacement for spherical joints versus only 7.90mm for pivot joints.
As the below table shows, because the pivot joints can resist the out-of-plane forces, both the pivot joints and the rigid joints show a bending moment in the linkage rod, whereas the spherical joints have no bending moment.
Linkage rod connectors are a fast and easy way to model connecting bars in your SOLIDWORKS Simulation, without having to create physical geometry. Another advantage is that the user avoids the overhead of meshing the linkage rod – SOLIDWORKS Simulation takes care of that for us in the background.
I hope this part of the What’s New series gives you a better understanding of the new features and functions of SOLIDWORKS 2022. Please check back to the CATI Blog as the CATI Application Engineers will continue to break down many of the new items in SOLIDWORKS 2022. All these articles will be stored in the category of “SOLIDWORKS What’s New.”
Simulation Product Specialist
Computer Aided Technology