Yaw Rate
Yaw Rate
(OP)
Hi all,
I have an question about the yaw rate of an vehicle. I have simulated the fmvss 126 test with an van with standard suspension and with air suspension on the rear axle. I want to explain the difference in the graphs but I cannot tell what this is.
Can anyone tell me what is an big influance on the yaw rate of the suspension?
By the way the things that are replaced on the vehicle are the lear springs for an half leaf spring with air bellows, shock aborbers and bumpstops. Practicly everything.
I have an question about the yaw rate of an vehicle. I have simulated the fmvss 126 test with an van with standard suspension and with air suspension on the rear axle. I want to explain the difference in the graphs but I cannot tell what this is.
Can anyone tell me what is an big influance on the yaw rate of the suspension?
By the way the things that are replaced on the vehicle are the lear springs for an half leaf spring with air bellows, shock aborbers and bumpstops. Practicly everything.





RE: Yaw Rate
RE: Yaw Rate
Hint. Reaction rate of compression to load applied of leaf spring vs air. Hint hint, spring leaves have friction between the leaves.
Deflection causes bump steer. Bump steer is yaw.
Regards
Pat
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RE: Yaw Rate
There is a difference in behaviour in the second set.
Almost anything can affect the on limit behaviour, and 30 to 40 deg/s is basically limit behaviour.
Cheers
Greg Locock
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RE: Yaw Rate
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Yaw Rate
I forgot to say, the vehicle has only one leaf spring so there cannot be friction between the leaves that causes the difference. The reaction rate of the compression of a lear spring vs air is causing the main difference. That is true, but I want to know why the graphs are different. Bump steer I havent thought of that yet. In the attachment I placed the characteristic of the leaf spring, and air suspension in loaded and unloaded condition.
By the way, thanks for the answers so far!
patprimmer
RE: Yaw Rate
You'll probably find most components have little effect. Then run K&C on the remaining parts.
You'll probably find load transfer is vitally important.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Yaw Rate
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Yaw Rate
Because there are no changes done in the geometry of the suspension, I didn't change that. I only can conclude that the suspension is the biggest factor in the difference in yaw rate. Also the load transfer has an big influence, but I am comparing the results of the yaw rate in unloaded and loaded condition.
RE: Yaw Rate
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Yaw Rate
Is the air suspension model complete with gas dynamics or is it just another spring?