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## Simulation Mechanical and Multiphysics

Active Contributor
Posts: 30
Registered: ‎12-19-2011

# MES Simulation of Gears

562 Views, 3 Replies
01-23-2013 09:40 AM

I have a 2D gear model that I am trying to run in MES. I have a prescribed displacement equal to 1 tooth on the large gear so that I can examine the the displacements and stress through the 6.1 degrees of rotation. Based on  the rpm of the gear the time of the event would be about 0.0326 seconds. I get results that are obviously based on rotating the gears from 0 to 115 rpm during that time based on the inertia of the gears.

My question is: How do I exclude the inertia from the analysis? I can use a longer time period but does that have an effect on the contact stresses at  the teeth?

I have not used MES much so any help would be appreciated. Thanks

Valued Mentor
Posts: 494
Registered: ‎08-30-2012

# Re: MES Simulation of Gears

01-23-2013 10:36 AM in reply to: nosborne

Nice gears.

Most formulas for inertia include the mass, so setting the mass density to 0 could be one solution.

But MES often has problems if all of the parts have 0 mass. A better solution would be to give all of the parts an initial rotation (Setup > Loads > Initial Velocity). Naturally, you will need to provide two initial velocities because the center of rotation is different for the gear and pinion.

John Holtz, PE
Mechanical Engineer
Pittsburgh, PA

16 years experience with Simulation Mechanical
Active Contributor
Posts: 30
Registered: ‎12-19-2011

# Re: MES Simulation of Gears

01-24-2013 05:26 AM in reply to: AstroJohnPE

Thanks for the help John. I will give it a try. I tried using zero density materials but the model would not run at all.

Employee
Posts: 209
Registered: ‎10-04-2010

# Re: MES Simulation of Gears

01-29-2013 11:56 AM in reply to: nosborne

The reason is that you are using "MES with Nonlinear Material Models" type, which need mass matrix in the equation.  So zero density is not allowed.

-Shoubing

nosborne wrote:

Thanks for the help John. I will give it a try. I tried using zero density materials but the model would not run at all.