Ride frequency and Time lag calculations
1. Because as the deflection of the wheel and spring is related by a constant. Force on wheel and spring is related by a constant. As the ratio of the above two also gives another ratio which relates the Wheel rate and spring rate. It will be same in the Leaf spring suspension as motion ratio is the same.
`Kw = Ks (MR)^2`
2. As the vehicle has motion ratio the force transmitted by the spring to the vehicle will be more than the wheel to the suspension due to mechanical advantage. Due to this, there will be a difference in the ride rate to wheel rate.
3. No, it is not recommended.
i) For low-frequency range, there should be more damping coefficient
For High-frequency range, there should be less damping coefficient
ii) For compression low damping coefficient is required
For rebound, high damping coefficient has to be used
4. As there will be a time lag between the front and rear ride frequencies when there is the same amplitude and are in out of phase. as this causes pitching. To make this in in phase the ride frequency fo rear should be greater than the front.
5. i) Low unsprung mass
ii) Low damping
6. As in the air suspensions, the ride height and spring stiffness can be easily altered Due to which the rede frequency can be altered according to load and ride conditions. That\'s why air suspension is beneficial.
7. Sprung mass natural frequency = 1.08 Hz
Unsprung mass natural frequency = 11.98 Hz
The calculation is shown in figure 1.
8. Case 1. 0.417 sec
Case 2. 0.144 sec
Time lag due to wheelbase is 239.55 sec
In the first case, the front time period is less than rear in which front oscillates more than rear in a certain period of time in which rear cant the front there will always pitching motion.
In the second case, the time period of the front is greater than rear in which rear can be able to catch the front so that there will be a flat ride.
For the flat ride, the time lag due to the wheelbase has to be compensated by the time lag by ride frequencies
Time lag compensated by wheelbase lag is in case 1 is 0.192
Time lag compensated by wheelbase lag is in case 2 is 0.078
After hitting the rear axle, the rear can be able to catch the front after the two time periods. Case 2 set is prepared for a flat ride rate.