Bolted frame

[Anonymous]

Hello,

I'm going to build a non welded go-kart but before I start building I want to make a design so that I can do some simulations first. However, I can't find a way to create a frame that's bolted together, can anyone help me with this? The goal is that I can do a simulation based on the fact that the frame is bolted together so without any welds.

Thanks,

[James.Youmatz]

Hi @Anonymous,

So Fusion doesn't have a frame generator like Inventor does, but it can be built using sketch profiles and then either using sweep, or pipes to create the frame components. For the bolts, as long as the bolt holes are included in the frame - the actual bolts are not necessary.

In the stress analysis - you can specify the bolted connected of the holes. 

Let me know if you need more info. I would start by planning out how you are going to build the frame members.

Thanks,

[Anonymous]

If I use the bolted connections in stress analysis does the program see the bolts as the only way the pipes are connected? 

[James.Youmatz]

Hi @Anonymous,

It depends on the contact between the bodies. Let's say you have two parts of your frame that are connected, and are defined as Bonded contact. Then no, the bolted connection will not be the only way the pipes are connected. These all come when defining your simulation study. Here is a decent resource explaining this. 

[Anonymous]

So which contact mode should I use than?

[James.Youmatz]

Hi @Anonymous,

Depends on the type of contact you need in order to define your simulation. Without seeing a model, or understand what you are trying to accomplish with the results of your simulation - I am only helping you get set up with the simulation. I would first model the frame (hold off on modeling fasteners for now), then set up a simulation based on the constraints and loads you know. I am more than happy to help when you get to that step, but right now without a working model we are speculating.

Thanks,

[Anonymous]

This is the model I have right now: https://a360.co/2q728JQ

[James.Youmatz]

Hi @Anonymous,

Thanks for sharing. For starters - I would start by defeaturing some of this. This article here goes into what to look for when defeaturing. Really the only things I would do on your model in terms of Simplify is cleaning up the bracket for the wheels (so that it meshes cleanly), and also removing interferences if possible. I got a warning that interferences exist when entering the Simplify environment.

Regarding the simulation itself. I would start by adding Constraints, as this model is fully unconstrained. In my eyes - the wheels and axle will be "bonded" contact, meaning they operate as one entity. Then, I would add either a frictionless (or perhaps pin) constraint to each axle and bearing. Then, the bearing would have bonded contact with the entire bracket assembly, and thus bolted connection to the frame. I would then add all your bolted connections and run automatic contacts. Just make sure that when checking the Contacts manually, that you are not using bonded for all the constraints - as you will have bolted connections. Without testing, I'm not sure if automatic contacts will pick this up or not.

Thanks,

[Anonymous]

Can you check if I did it correct?

[Anonymous]

I don’t really understand the contstraints can you clarify that for me?

[James.Youmatz]

Hi @Anonymous,

What do you need specific help with? For the most part, I would guess you would use frictionless constraints for the axle, bolted connections for the bolted areas, and potentially fixed constraints depending on which bodies are considered bonded together and are free to move. Utilizing rigid body connector here may be the way forward.

For starters though, what are you trying to learn by running a simulation on this go-kart? Are you looking for areas of failure, or high stress points?

Thanks,

[Anonymous]

I want to find out how thick my steel pipes need to be.