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 Shock Absorber Valve Shim Deflection Formula Post Reply Engineering Forum
 Posted by: jamiedaugherty ® 01/12/2009, 08:10:43 Author Profile eMail author Edit I'm wanting to develop a formula (or series of formulas) to predict the behavior of shock absorber valving. Ultimately what I would like to do is be able to generate the velocity of the shaft under a given load for a particular valve configuration. To begin with I'd like to develop a means to determine the deflection of the valving shim stack.For those who are not familiar, a modern shock absorber uses a valve piston that flows the oil freely in both directions. The ports in the valve are capped with a stack of thin shims when, under pressure, will deflect to open the ports and allow the fluid to pass.What you have is a situation where the shims are deflecting under a constant distributed load (the fluid pressure coming through the port) but not over the entire 360° of the face (ports are not totally annular). The last part I'm not that concerned with as I think I can take care of it separately. I've thought about using the disc spring formulas but 1) none that I have found show deflection for a distributed load over the face and 2) the shim starts as a flat and bends upward, which is the opposite of the disc spring.I'm almost sure that I've seen something on here before concerning this but I was unable to find it in a search. Please help!

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 : Shock Absorber Valve Shim Deflection Formula : Shock Absorber Valve Shim Deflection Formula -- jamiedaugherty Post Reply Top of thread Engineering Forum
 Posted by: jamiedaugherty ® 01/13/2009, 12:39:28 Author Profile eMail author Edit As a follow up, I have found the following information on eFunda:http://www.efunda.com/formulae/solid_mechanics/plates/calculators/apFC_PRing.cfmI think this is real close. The only problem I can find now is that the valve shims are stacked 6+ per side. These shims are decreasing in diameter. The formulas in the link are ok for a single shim, but what about multiple shims in series? I'm hoping someone can give me some guidance so I don't have to work this out the hard way!Thanks!!!