[Silver Supra]

Originally Posted by TachyonBomb

..

On a side note I noticed that a lot of spring rates for springs are kind of missing. There may be a simple way to calculate the spring rates for all those springs.

The equation for the spring force is:

k*Distance=Spring force or force on spring
-(k) is the variable used in physics for the spring constant which I believe is interchangeable with how the automotive industry used the phrase "spring rate".

And the downward force of any mass due to earths gravity is:

Mass*9.8m/s=downward force

So if someone has one of those fancy 4 wheel alignment machines that displayed weight distribution and if someone would make a set of dummy shocks that lifted the car to the point where the springs are not compressed yet they are installed at the max uncompressed height. One could use this equation:

k*distance = Mass*9.8m/s

to make this equation:

k=(Mass*9.8m/s)/distance the spring compressed in meters

where the mass could be the original weight of the car plus some extremely fat friend you talked into hopping in the car while on the alignment/scale machine. You can measure the distance each spring compresses and enter the info in the above equation and that should give a rough idea of the spring rate for each spring.

This is what physics calls the static spring rate.

BUT!!! If spring rates and shock rates in the automotive industry are based on a time derivative (fancy way of saying how something changes over time) then that would require a differential equation and a measurement of how fast this spring or shock is recovering after being compressed (the measurement after you let go of a spring and how much time it takes for the spring to rebound to its max height.

I don't see why a spring would need this version of measurement but the shock will need to go through this measurement since it "damps".

damp = slows down the wave (of a bouncing/oscillating spring)

So you're measuring the change in force over time as the spring exerts from its max force (once let go) till no force is exerted (spring reaches max uncompressed height).

That equation looks a little funkier and needs a precise timer. So lets just forget about the shocks for now.

So ya if @Racecomp Engineering has one if these machines, a shock that provides no damping force and some free time to work some of this stuff out it is not impossible to find the spring rate of any spring on the market.

I'll be expecting my letter of recommendation before the November deadline thank you very much. End Tangent lol

Originally Posted by Silver Supra

... A unidirectional spring is a spring but may respond differently to high frequency movements....

Oh, you will be in academics. Trust me.

I am pretty sure the manufacturers test single units in a dynamic loading apparatus, not on a car.
The equation of motion for axial force and displacement is relatively simple:
Say axial displacement = X
velocity V = dX/dt
acceleration A = dV/dt
relevant mass = M
Damping = C
spring rate = K
equation is
F(t) = M*A + C*V + K*X
but the damping C and spring rate K (and even mass, M) may be nonlinear with X so it gets interesting.

It's all to say it may make some difference in response - or maybe not, but the manufacturer had a reason for the defined configuration.

I suspect the OP will think twice about starting another thread!!