Altair RISE

A program to recognize and reward our most engaged community members

Nominate Yourself Now!

How to set Contact Properties in Motionview/Motionsolve.

Hello. I have been trying to use motionview/motionsolve for calculating bearing reaction force but i keep on ending up with a result with too much fluctuation.

My set-up is comprised of 4 gears meshing with each other and bearing for each of the gears.

I Tried to reduce the fluctuation by adjusting values in the COntact Properties and it somehow work after several trial and error.

Is there a proper way to determine contact properties for IMPACT?

What are the appropriate values for Stiffness, DAmping, Exponent?

And what are the best settings for gears contact? Impact, Poisson or volume model?

Thank you in advance

Find more posts tagged with

English

MotionView/MotionSolve

Accepted answers

All comments

Scott_Z_2

Hello,

You did not indicate what types of gears you are modeling. Spur gears will obviously have non-continuous, intermittent contact behavior (to some degree) and will expectedly show periodic spikes. A worm gear arrangement on the other hand will be continuous and should show fairly smooth contact forces.

The MotionSolve contact settings to be used as baseline values in a problem strongly depend on things such as 1) quality of the geometry at the contact interface (Mesh resolution) 2) component mass (Stiffness), 3) relative velocity (Damping), 4) duration of the event (Units... sec or millisec), 5) if there are external loads applied of large or small values.

Contact problems have many variables to consider, and it really makes for a larger discussion. There is some good documentation in the HyperWorks Help on Contact best practices that helps explain the theory behind contacts and also it and how to adjust in certain situations: MotionSolve Contact Best Practices

I suggest you begin there and see if that helps get you on track.

Scott Z

AnanthK

In addition to Scott's excellent answer above, using contact force based representation of your geartrain is a bit overkill just for bearing reaction loads. Unless you're trying to study design robustness or you expect significant force variations due to shape of the gears, in which case your CAD needs to be of really good quality and attention must be paid to the mesh that is often auto-generated. Contacts are a solution that appear really easy to setup, but in reality they are not because of the sensitivity to CAD and meshing quality. Also, finding the properties for the variables you mentioned can be rather challenging.

Usually rigid-bodies and coupler constraints to represent the gear reduction are sufficient to extract loads at the early concept stage.