Learning Forum

[XU5855]

Hello, everyone!I am researching time-varying meshing stiffness of gear,  in the Transient Structural module , stiffness value seems to be unable to get directly, so I choose to get the value of gear meshing contact force and contact deformation which related to the stiffness value , but through the related resources i can not find out about the contact force and contact deformation process of solving way and it's make me upset.In addition, when I tried to solve the stress and strain, I finally received the prompt "An unknown error occurred during solution. Check the Solver Output on the solution Information object for possible causes", but I did not know where to set and how to set.The relevant Settings and problems in the process of solving are shown in the figure. Therefore, I really want to get your help and discuss the relevant solutions with me.I hope to get your advice and guidance as soon as possible.

[peteroznewman]

 I see you are researching time-varying meshing stiffness of gear, and obviously, gears move, but that doesn't mean you have to study the stiffness in a Transient model.  It is a lot simpler to study stiffness in a Static Structural model. What do you mean by time-varying?  Do you mean the time from when the tip of tooth 1 first touches the base of tooth 2 through the time when they touch at the pitch circle, and ending at the time when the base of tooth 1 last touches the tip of tooth 2?

[peteroznewman]

Read some of the other discussions on Gear Mesh on this site. Go to Google and paste the following line into the Search bar.

site:studentcommunity.ansys.com gear tooth stress

 

[XU5855]

During the engagement of the two gears, different contact forces and contact deformations will occur due to different contact positions. If there is no interference factor, the contact force and contact deformation between the two teeth are the same. Then the change in the corresponding stiffness is definitely cyclical. Now, a vibration excitation is applied to the gear, that is to say, even if the same engagement position, the gear will produce different magnitudes of contact force and contact deformation during the engagement process, then the corresponding The contact stiffness changes to exhibit a non-periodic change. What I am confused about is the reason why "Solver Output" has an unknown error, and I don't know how to solve the contact force and contact deformation. It is really embarrassing.

[peteroznewman]

I agree the contact force will be the same, but I disagree that the contact deformation will be the same because that contact force starts at the tip and ends at the base of the gear and the tip is more flexible than the base so for the same force, the deformation has to be different.

Try using a very small Initial Time Increment. Like 100 times smaller than you have now to see if that lets the solver begin.

[XU5855]

I mean, after adding vibration excitation to the gear, the corresponding contact force and contact deformation will change, and it is not linear change, so the corresponding stiffness is also changing...The initial time increment I set is very small, but I don't know how to set the output solver. What's wrong with the output solver at present

 

[peteroznewman]

Clear Generated Data on the Mesh, then save the project, then use File > Archive to save a .wbpz file. After you post your reply, you can attach that file to your post with the Attach button.

[XU5855]

I have cleared Generated Data on the Mesh, and the relevant data has been set (vibration acceleration, speed and torque), so the corresponding contact force and contact deformation need to be solved.Thank you very much for your help!

[peteroznewman]

I don't know how to set the initial conditions to have a rotational velocity for the Transient simulation. You don't want a step change in rotational velocity, since that generates too much stress.

I recommend the rotational velocity be ramped up from zero over some time.

[peteroznewman]

If you delete the chamfers from the edges of the teeth, the gear solid body will become sweepable and you can greatly reduce the number of nodes and elements needed to mesh the bodies.

[XU5855]

I know that the chamfering of the top portion of the tooth removes the number of nodes and elements needed to lower the mesh, but the chamfering of the root portion will cause stress concentrations. How do I set the contact force and contact deformation for solving the gear meshing? It is really an annoyance,embarrassing????

[peteroznewman]

I'm not talking about the chamfer/fillet at the root, that is not preventing the body from being sweepable. I am talking about the chamfer on the tooth tip on the side face which has nothing to do with deformation.

[XU5855]

That's right, peteroznewman, do you know how to solve contact forces and contact deformation? I have not found any examples and guidance on the reference books, which makes me unable to learn how to solve

[peteroznewman]

I recommend you first calculate using a Static Structural model which is easier to solve than the transient.

If you don't want to do that, I recommend the rotational velocity be ramped up from zero over some time.