Friction / Damping Calc

[CondensedMatter]

I'm designing a spring with spring washers (belleville type).

I'm looking for formulas to calculate the damping / frictional effects of stacking them unidirectionally.

The stress / deflection formulas are easily found.

 

[sreid]

Key Bellevilles list the hysteresis in parallel unlubricated stacks as

2 +/- 4 to 6%
3 +/- 6 to 9%
4 +/- 8 to 12%
5 +/- 10 to 15%

The "+" is the gain in force on compression and the "-" is the decrease in force on relaxation.

 

[CondensedMatter]

I just derived the formulas and that matches pretty close.

Thanks