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Estimating spring coeff and damping coeffient of my car 
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#1
Jan813, 09:18 AM

P: 19

I'm working on a project, I just need ballpark estimates for the spring constant and damping coefficient for my 1994 Nissan Pathfinder SUV.
I was thinking of using Hookes law to estimate the spring constant, can I just measure the ride height of the car with nothing in it, then add 200 pounds of weights in the back and measure the displacement from the reference to get the spring constant? For the damping, I know most cars are near critical damped right? to make oscillations die out fastest. I'm using the quartercar model for my project and I just need to estimate these two parameters on a real car Any advice or suggestions would be awesome. I know damping they used to do a drop test and watch the oscillation for a "shock" test but I dont have the tools or a jack to safely do this 


#2
Jan813, 02:23 PM

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#3
Jan913, 01:21 PM

P: 19

So you mark a reference point, jack the car up until the tire barely lifts off the ground, that distance from the reference is the displacement, and I use the car weight as the force as listed in the owners manual? Or would I use 1/4 of the weight since its one tire?



#4
Jan913, 01:30 PM

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Estimating spring coeff and damping coeffient of my car



#5
Jan913, 02:30 PM

P: 19

Thank you!
For the damping, the halfcycles would be the peak to peak every time it comes "up" correct? If I video tape it I will just need to know the FPS of the camera to get a time scale like they do on myth busters? 


#6
Jan1013, 07:01 PM

P: 19

Confused :/ any help thank you AlephZero



#7
Jan1113, 11:55 AM

P: 19

If I count every time the car goes above the ride height that is a half sine (half of a cycle) ??



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