How to Use Symmetry in SOLIDWORKS Simulation to Reduce the number of Fixtures?

Did you know you can use symmetry in SOLIDWORKS Simulation to reduce the number of fixtures required to stabilize your model? Using symmetry in simulation will not only simplify your model (and therefore drastically improve run time), but it eliminates the need to apply additional fixtures and this will result in even more accurate results. Let’s look at the example below. A hub has been shrunk fitted into a rim and due to the shrink fit, the model is experiencing internal stresses.

Hub and Rim Assembly Created Using Shrink Fit

Since there are no external loads, the model is self-equilibrated, however, we still need to constrain the model in X, Y, and Z directions to account for mesh asymmetry, numerical errors, or solver errors that may result in unrealistic displacements. One way to do this is to select an entity on each of the bodies (one on hub and one on rim) and apply fixtures to them. This will not be very accurate and we may over constrain our model by fixing an entity on each of the models. The other solution is to use either Soft Spring or Inertial Relief to stabilize the model.

Using Soft Spring or Inertial Relief to Stabilize the Model

However, the most accurate and simplest way to stabilize this model is to use SOLIDWORKS Simulation symmetry. The model (and all its fixtures and loads) are symmetric relative to Front, Top, and Right planes. Therefore we can cut the model with these planes and analyze only 1/8 of the model which not only makes the simulation much faster, but because there is no need to turn on Soft Spring (or inertial relief) for stabilizing the model or to constrain an entity on the model by adding a fixture, our results will be closer to the real-life solution.

The Model Is Symmetric Relative to Front, Right, and Top Planes

As shown in the screenshot below, due to symmetry in three directions, the model is constrained in three directions and there is no need for any additional fixtures or special technique to stabilize the model.

Applying the Symmetry Fixture Will Also Constrain the Models Normal to the Planes of Symmetry