I was looking at the plastic deformation issues with a servo cover design and thermal stress. My motors don’t get too warm, but there have been a few issues in the past, and I was looking for a material that would hold up well to heat. While Simulation Mechanical was slugging along, I thought I’d spend an hour with my old friend Sim 360. I think it’s a positive reflection on software when you turn to it for relaxation… and yes this is what I was doing to relax (sad, but true).
I ran four scenarios as follows:
- static thermal analysis with a constant temperature of 200° F applied to the outer surface of my simplified servo body (sure it’s a lot, but I wanted to see what happened).
- Static Stress scenario, simple loading of gravity upon the signal connector, using ABS plastic
- Static Thermal Stress scenario, simple loading of gravity upon the signal connector, using ABS plastic
- Static Thermal Stress scenario, simple loading of gravity upon the signal connector, using Nylon
High temperatures and plastic don’t usually get along, but that’s expected. What is nice though is the ease that Sim 360 allows me to make comparisons.
I loaded the Decision Center, and selected the scenarios with the force loads. I then added goals, which were simply max/min factors for displacement, stress, and safety factor.
The results were nicely delineated, and allowed me to make a quick judgment on how the materials compared in this situation. Using the Compare Workspace option, users can graphically see their models and results side by side. They really have streamlined this process nicely.
It’s fairly clear that the more flexible Nylon experienced less stress, but may behave poorly overall. I used the Decision Center to review additional thickness possibilities as well, which took all of 5 minutes to create a new scenario, add thickness to the main shell body, and rerun the analysis.
Simulation Mechanical will do a great job computing the non-linear thermal stress analysis for the plastic deformation, which will allow me to see just how badly the component will be permanently deformed. That process may take a little while (understatement). Sim 360 provides a quick, easy way to compare substituted materials, in order to find a more realistic starting point, prior to the lengthy transient analyses.
What I am Looking Forward to
Sim 360 only handles linear analyses at this point. The ease of use is off the chart, and the ease of applying multiphysics loads couldn’t be simpler. Unfortunately I need two things rather badly.
- A materials editor and/or the Simulation Mechanical materials database for plastic properties
- Non-linear stress analysis with non-linear material properties
Once these two features are added, the capabilities of Sim 360 will span a very large need in the validation sphere, and do it easier than anything else available.