Learning Forum

[OJPN6685]

Hi Everyone,

I'm attempting to do a 3D simulation in ED to show total deformation/ velocity of a tyre and rim hitting a curb. I am a total novice and only started learning this software a couple weeks ago. Please be gentle.

I'm running into a few errors and for the life of me I can't figure out.

1. Solver error - time step too small.

[peteroznewman]

I recommend you start with a much simpler model to learn Explicit Dynamics. For example, don't have so much detail, make a very simple tube shape. This allows you to have larger elements which allow ED to take bigger time steps. There is an example in this discussion: /forum/discussion/22403/can-anyone-help-me-to-do-explicit-dynamics-for-turning-operation
When you have a tyre rolling along the road, do you want to simulate just the tyre with no car as if you were rolling the spare tyre by itself, or do you want to simulate the tyre connected through a suspension spring to the mass of a car?
Do the tyre on its own as a first simulation. I suggest you have an Initial Condition where the tyre spins about its axis. I had problems with a model this simple as you can read about in the links in the discussion above.
For a second simulation, add the road with bump with an initial velocity toward the tyre. Use a velocity constraint to keep the road with bump traveling in the -Z direction at 2.e+4 mm/s which is about 75 km/hour. I don't believe you want an initial velocity of 2.e+7 mm/s which is 75,000 km/hour. Yes, the road will move toward the tyre rather than have the tyre move toward the bump.
If the tyre has a 600 mm diameter, the radius is 300 mm. When the road is traveling at 2e+4 mm/s that means the angular velocity of the tyre is 2e+4/300 = 66.67 radians/sec = 159 RPM so the road speed and tyre surface speed are equal.
Don't use any contact. ED will automatically add Body Interactions. That is all you need. Make the density of the tyre 1000 times larger that reality to make the simulation time step 10 times larger which will reduce the simulation time.
Since you will have the tyre spinning and the road moving as initial conditions, position the bump so it is tangent to the tyre. That way, the simulation can begin at the time of impact and you don't have to waste computations where two bodies move with nothing interesting happening.

[OJPN6685]

Thanks for the reply Peter.
I just need to simulate the tyre with no car.
I followed the simulation with a basic model and had the model spinning on its axis. That works fine.
I copied the same values into the main project, however this won't spin (time step too small)

[peteroznewman]

I used to have the ability to work in ANSYS Student 19.2 but that got broken with the installation of the last version of ANSYS Student 2021 R2. If you can find a second computer to install ANSYS Student 2021 R2 on, you will be able to open the attached archive. ANSYS 19.2 cannot open the attached file.