Spring Damping Constant 1

[GEspo]

Hello. I'm working on modeling a coil spring in my Advanced Systems Modeling software. There is a damping constant value that needs to be set so that the spring will stop oscillating at some t.

(heres info on damping ratio

https://en.wikipedia.org/wiki/Damping_ratio)

Suppose we take a compression coil spring of 3(ID) x 12(resting L) x 500(lb rate).. if we place a 500lb weight on it the spring will compress 1". The damping constant, as far as I can tell, changes how many times the spring will oscillate before reaching equilibrium.

I have reached out to the manufacturer of the springs I'm modeling and they said they didn't have info on damping constants.

Thoughts?

 

[GEspo]

Thanks for all the help in this, very much appreciated. After testing a bit more w/ the software I'm finding setting the software damping value as low as possible may be a better approach than the idea of adding mass to the spring and damping the vibrations which occur at "rest".. Anyone have any studies or tests done on real springs(coil compression preferably) so I have a bit of real world data to begin? Thx

 

[SwinnyGG]

You don't need data from 'real coil springs' - just data for the material. There are sensible values already posted in this thread.

 

[rajubhaiya]

Does natural frequency effect suspension frequency? By the math it does but suspension guys will often tell you it doesn't do much or help. What matters is the periodic changes in the surface being driving on which is a resonant frequency that's constantly changing. Sometimes greatly and sometimes minimally. When looking at a suspension in terms of mass and a system you also have to consider the differences between sprung and un-sprung mass and weight. There's also rotating mass to consider which can be effected by the simple property of brake location.

 

[GEspo]

Thanks for the comments. Anyone have any experience or recommendations for 3D multi body dynamics software? I'm noticing I may be pushing my software capabilities to the max with 8 shocks and multiple joints in my model... Recurdyn looks interesting, wondering if I can do vehicle dynamics studies with it, as in get data from the model on tire slip and other basic dynamics metrics... I know a bit about Adams, but interested in any others that are highly customizable and have hydraulics libraries or allow for construction of custom components, namely modeling the monotube and bypass shocks(hydraulic dampers) to be used in a multi body model... thx

 

[GregLocock]

It really does depend what you want to do. If you are explicitly interested in complex shock absorber models then I'd use Simulink rather than a vehicle level simulator.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[JamesCrist]

Recurdyn could be a good option especially when looking at non-linear spring behavior like self contact, it handles large numbers of bodies well. They have toolkits for quite a few things including tires and springs, here's a page that talks about the spring one (

https://enginsoftusa.com/RecurDynMBD/RecurDyn-MBD-Other-Toolkit.html).

For customization their API lets you build custom tools.

Senior Application Engineer
enginsoftusa.com