I tried to use Abaqus for external turning simulation, set the workpiece speed to 6.28/s, and set the analysis step time to 1. Theoretically, the workpiece should rotate one revolution, but the output shows that the workpiece reference point did rotate one revolution, but the rotation involved in cutting seems to be only a small rotation.
1. the following figure 1 shows my boundary conditions set for the workpiece(figure 2 shows the workpiece reference point is coupled to the left cross-section.).
2. And the following figure 3 shows the output rotation angle of the reference point on the workpiece.
3. The cloud diagram 4&5 below shows how little the workpiece actually turns.
Hi Yh Chen,
You just need to create an Amplitude for your boundary conditions. Your velocity needs to be continuous. You see, your current boundary condition has no amplitude, and the angular velocity you specified will be applied instantaneously. It’s like applying initial velocity, so if the part makes contact with an object like the tool, this slows down the rotational speed. That is why it rotates with a small amount in the cutting process.
Therefore, create an amplitude. For example, see the figure I attached.
Also, I suggest checking the link below. It will give you useful information to resolve your future problems.
https://caeassistant.com/product/abaqus-for-beginners-mechanical-engineering-copy/
Best wishes.
Dear Yh Chen, as I said before, when you create an amplitude, the model is forced to move. Like the real turning machine in which the motor rotates the workpiece. By the way, how did you determine the rotation angle of the model and realize that it is small?
I think your model rotates, but you can’t see it because your time increments are large. Try with a smaller time increment to see the rotation.
Also, another trick is to make the workpiece steady and rotate the tool in the opposite direction of the workpiece rotation.
I hope I could have helped you.
Best luck.
Dear Martin Veidt, thanks for your help, I think your answer is very helpful.
I see it from the length of the machined surface (chip is also possible), I found a problem with the mass scaling factor, I tried to change the mass scaling factor and it got better. But I think the rotating cutting process is dynamic, can I use the mass scaling factor (which I have been using before)? It's ridiculous, the internal energy shown is even 5% of the kinetic energy!
Dear Yh Chen, Generally, the model must be quasi-static in the forming or cutting analysis. Therefore, the kinetic energy must be less than 5% of the internal energy. Check the link below. It is an article that could help you a lot.
https://caeassistant.com/blog/speed-up-quasi-static-in-explicit-1/
Also, you can use the mass scaling factor but check it so your model won’t turn into a dynamic one.
If you need more information about mass scaling factor theory and examples of using it, refer to the link below.
https://caeassistant.com/product/abaqus-for-beginners-mechanical-engineering-copy/#1576702296965-155e826a-9aae
Best regards.
Dear Martin Veidt, Thanks for your recommendation, through the website you suggest, I have known the load rate is usually the velocity. but the boundary condition I set for the workpiece is velocity/angular velocity. It's not displacement/rotation, So it seems reducing the step time to speed up my simulation doesn't work. I don't know how to increase the load rate under the situation that I don't change my boundary condition and the final rotation of the workpiece. or do I have to change the boundary from angular velocity to the rotation and tune the step time simultaneously?
Dear Yh Chen, as you said yourself, you need to change the boundary condition from the angular velocity to rotation and decrease the time period to decrease the analysis time. But, remember to check the energy levels and quasi-static-related matters. Also, you can use mass scaling.
I hope you can resolve your problem.
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