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Problem set 3, week 3 VD with Matlab

Front Ride Rate: 200 lb/in

Rear Ride Rate: 250 lb/in

Parameter Value Units
Total Roll Stiffness(front + rear)

Sprung Mass Roll Moment(H-arm)

2400

1.61

ft-lb/deg

ft

1)Roll Moment (Sprung mass*H-arm(ft))/per g) 7240.5 ft-lb/g
2)Roll Gradient (Roll Moment/Total Roll stiffness) 3.016875 deg/g
3)Load Transfer due to Roll (Mass*cg height/L*per g) 1534.112 lb/g
Spring Stiffness 2769.228 lb/ft
Wheel Rate 4.430765 lb/ft
Track Width 4.888333 ft
4) Front Roll Stiffness at WC (negating the effect of tire stiffness) 52.93834 ft-lb/deg
Front anti-roll wheel rate at one wheel 4.533572 lb/in
5)Front anti-roll Spring rate at one wheel 18.13429 lb/in
Front Anti-Roll wheel rate for roll 9.067143 lb/in
6)Front Anti-Roll spring rate 36.26857 lb/in
7) Front Anti Roll Bar Stiffness (how to calculate?) 20.51 ft-lb/

I calculated the above values. I also have to find the auxiliary roll stiffness % but I do not know what that means.

The input values are attached as an image below.

 

Problem set 2 -week 3 challenge
Vehicle Dynamics using MATLAB

This challenge tests your understanding anti characteristics and pitch elimination

3, To eliminate the pitch angle (theoretically), keep the rear swing arm height fixed at 16 inches from the contact patch. Calculate the following (12 points)

  • Front anti-lift % and rear anti-squat % for zero pitch angle.
  • Front end deflection under load, accounting for the new anti characteristics.
  • Rear end deflection under load, accounting for the new anti characteristics.
  • Pitch angle, accounting for the new anti characteristics (verify that it is indeed zero)

Pitch angle=arctan(front suspension deflection under load(zf)+ rear suspension deflection under load(zr)/wheelbase)

In order to make pitch angle zero, zf=zr. Zero pitch angle would mean that anti characteristics would have to be 100% right?

Input values are attached below

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