SOLIDWORKS SIMULATION TECH TIP: Shrink Fits and Press Fits

When studying shrink fits and press fits, we have a couple of options in SolidWorks Simulation; I would like to explore a couple of them in this post. If we just care about the end result, we can use the “shrink fit” contact sets. This technique is available in linear static as well as non-linear studies. Using the shrink fit option, the solver will attempt directly solve for the deformation of the male/female interface in its final condition.

 

If we want to evaluate press fit forces and want to see what’s happening during the press operation, we will want to use non-linear simulation, which solves for the final answer as well as the steps in between. Here is the force response of a press fit simulation:

 

We can easily extract forces from fixtures by right-clicking results, choosing List Result Force, and selecting the entity such as face or edge to see the reaction forces at that fixture during the simulation. To view the time history response of the fixture, click the little clock icon to get a plot across all steps of the study:


The type of contact we select is different for this approach. In this case we would use the “no penetration” contact sets instead of the specialized “shrink fit” contacts. If you are new to simulation, “no penetration” contacts are a pretty literal definition: the face sets selected are not allowed to penetrate each other during the simulation.

Since we do not know the insertion forces, rather than applying a force to the pin face, we use an advanced fixture on the pin face to control the motion of that face (or edge if using 2D simplification). We then use the “result force” tool discussed above to determine the forces required to create the motion.


Here is the final answer for a linear shrink fit study versus non linear study where we pressed in the pin. As we can see, the final hoop stress is identical. Lastly, it’s worth noting the linear analysis was run in 3D and the non-linear study was run using Axis symmetric 2D simulation to save time.

To see an example of both models, check out this short video:


Happy Simulating!


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FISHER/UNITECH
FISHER/UNITECH