# 8-bit Simulation - Hot Tracks, Cool Trucks

by 25 April 2016

So you just saw me destroy the completion in R.C. Pro AM, but we all know the Peach truck is about to nitro boost past and lap me in no time…jerk.  To keep up with him we’re going to have to make sure ol’ Red is up to the task, and doesn’t over heat in the process. Autodesk Fusion 360 has everything we need to do it in one spot.

To begin, with the model open in Fusion 360, change from the Model environment to Simulation by clicking on Model and choosing Simulation.  Once in the Simulation environment, you are able to choose to set up a new study and select thermal to define the analysis type.

The next step is to define the material properties for each part of the design. The wheels will be set to Rubber, the battery to Nickel-Copper Alloy and the rest of the body to Plastic. Sure, the axels are going to break when they hit a bump, but have you ever used an RC car? That’s pretty much how it works out of the box…

To represent the heating of the battery and how that heat dissipates through the truck, we must apply 2 different thermal loads. First, with everything but the battery selected, choose Load: Convection. Define the convection value to be 1e-6 W/ (mm^2 C) with an ambient temperature value of 20C. Next, with just the battery selected, choose Load: Internal Heat. Check the box for Unit Volume and input an internal heat value of 3e-5 W/mm^3.

Since all of our parts are initially in contact, the next step is easy. Just click on the contact drop down and choose Automatic Contacts. This will create a bonded contact set anywhere that surfaces of two parts are in contact, allowing for complete heat transfer from part to part. To ensure that all parts are in contact you can click the green and red Display button. A completely green truck will indicate all parts are conducting heat.

Now you’re all set to press Solve! In just a few seconds you’ll be able to review the running temperature of your truck, which appears to be almost 138F. What? You’re viewing in Celsius? No worries. Go click on the pencil next to Units in the model tree and switch over to U.S. (in). You can hide the parts with a high or low temperature by clicking and dragging the legend, but it is clear to see that the plastic body is too warm.

Now how do we cool this truck down? Well we could force more cool air around the battery, or change the materials of the body or around the battery, but come on, I spent 100 bucks on this thing. I’m not going to spend more keeping it from overheating.  How about we just reduce the battery size. We might have a shorter runtime, but just so we can finish the track and put in a fresh battery we should be ok.

Back to the modeling environment we go. With one simple Press/Pull command the battery can be made half the original size by pushing the face back 0.5 inches. Back to the simulation environment one last time. Here we see there is a warning in the bottom right corner telling us that our results are not up to date. Lucky for us, all of our loads and materials are still remembered, so pressing Solve updates our results. The battery is now only running just over 100 F, with most of the truck body just over room temperature. I would say this RC truck has been successfully cooled.  Time to get revenge on the peach truck!

Did you miss the video and stumble on this blog post somehow else?!? Well make sure to check it out below, and see if you can beat my time! I dare you!