Vehicle Ride 1
1.i)Front sprung mass natural frequency target at design is 1.15 Hz --> ffr
Wheel Base = 2700mm = 2.7meters
Speed = 50mph = 26.82mps
Tfront = 1/1.15 = 0.867sec
time lag dt = Distance/SPEED = 2.7/26.82 = 0.100 Sec
--> 0.867 = Trr + 0.100
--> Trr = 0.767Sec
--> frequency Rear Sprung Mass = 1/0.767 = 1.30Hz
ii) Front sprung mass natural frequency at design = 1.15Hz
iii) Front Spring Rate
Kw = Ks MR^2
245 = Ks (0.97)^2
Ks Front = 260.63 N/mm
iv) Kw = Ks MR^2
245 = Ks rr (0.85)^2
Ks Rear = 339.1 N/mm
v) Front and Rear sprung mass natural frequencies at curb and GVW
ffr GVW = 1/2Pi * (Krf/Ms)
Krf = Ks fr *Kt/Ksfr+Kt =126.28N/mm
Ms GVW / Wheel = 237.5Kg
ffr GVW = 0.11Hz
frr GVW = 0.195Hz
ffr Curb = 0.18Hz
frr Curb = 0.25Hz
vi) frr GVW = 0.195Hz and frr Curb = 0.25Hz
vii) Keq fr = Ks +Kt = 260.63+245 = 505.63N/mm
Keq rr = Ks +Kt = 339.1+245 = 584.1 N/mm
ffr GVW, curb and Half load = 0.37Hz
Viii) frr GVW, Curb and Half Load = 0.496HZ
ix) Frequency Ratio GVW Curb and Half Load = 0.5 / 0.37 = 1.35
2. Please guide me to do the 2nd problem