Springs in Series Compression due to Acceleration

[JCReynolds79]

Two springs in series w/different masses/rates. They are compressed some distance and "trapped" at this distance in a rigid frame. The springs' ends are attached to the inner walls of the frame. The frame is then accelerated in the axial direction of the springs.

How do I calculate how much the springs deflect?

Considering the springs are attached to the frame, one must stretch and one must compress and I believe it's the mass of the springs themselves that are going to drive things.

Thanks

Regards,

Jon Reynolds

 

[btrueblood]

Get a copy of (one of) Wahl's books, I have Mechanical Springs on my shelf. In there, Wahl gives a very good, detailed derivation of the dynamic equations of motion for helical springs. Treatment of the series springs is not covered (not clear why this is being done in your case, or what advantage is provided by two vs one spring) but is pretty straightforward. If one of the springs is much lower in spring constant than the other, you might be able to treat the heavier spring as a solid mass.

 

[btrueblood]

Also, see the discussion in this thread:

https://www.eng-tips.com/viewthread.cfm?qid=363297

Greg Locock posted a link to this

https://www.roymech.co.uk/Useful_Tables/Springs/Springs_Surge.html

which has some of the same derivation as given by Wahl.

 

[JCReynolds79]

Hey btrueblood, thanks very much for the steer. Very useful info thanks.

Regards,

Jon Reynolds