Vehicle Ride 2
1.
Total weight= 1900Kg
Total mass front= 0.55*1900=1045Kg
unsprung mass front=90Kg
Sprung mass front=1045-90 =955Kg
Total mass rear= 0.45*1900=855Kg
Unsprung mass rear=60Kg
Sprung mass rear=855-60=795Kg
Sprung mass critical damping
Front
c=2*sqrt(Kr*ms)
Kr=Ks*Kt/(Ks+Kt)
=20*250/(20+250)
=18.51N/mm
c=2*sqrt(18.51*955)
=265.91N-s/m
Rear
c=2*sqrt(Kr*ms)
Kr=Ks*Kt/(Ks+Kt)
=30*250/(30+250)
=26.79N/mm
c=2*sqrt(26.79*795)
=291.87N-s/m
Unsprung mass critical damping
Front
c=2*sqrt(Ke*mus)
Ke=Ks+Kt
=20+250
=270N/mm
c=2*sqrt(270*90)
=311.76N-s/m
Rear
c=2*sqrt(Ke*mus)
Ke=Ks+Kt
=30+250
=280N/mm
c=2*sqrt(280*60)
=259.23N-s/m
Sprung mass initial damping coefficient
Front
Damping ratio=0.7
Front sprung mass initial damping coefficient=damping ratio*front sprung mass critical damping
=0.7*265.91
=186.14N-s/m
Rear
Damping ratio=0.7
Rear sprung mass initial damping coefficient=damping ratio*rear sprung mass critical damping
=0.7*291.87
=204.31N-s/m
Unsprung mass initial damping coefficient
Damping ratio=0.2
Front unsprung mass initial damping coefficient=damping ratio*front unsprung mass critical damping
=0.2*311.76
=62.352N-s/m
Rear
Damping ratio=0.2
Rear unsprung mass initial damping coefficient=damping ratio*rear unsprung mass critical damping
=0.2*259.23
=51.85N-s/m
Compression damping coefficient
Front
Sprung mass=I/2=265.91/2=132.96N-s/m
Unsprung mass=I/2=311.76/2=155.88N-s/m
Rear
Sprung mass=I/2=291.87/2=145.94N-s/m
Unsprung mass=I/2=259.23/2=129.62N-s/m
Rebound Damping coefficient
Front
Sprung mass=3*132.96=398.88N-s/m
Unsprung mass=3*155.88=467.64N-s/m
Rear
Sprung mass=3*145.94=437.82N-s/m
Unsprung mass=3*129.62=388.86N-s/m
Low speed compression damping rate
Front
DR=critical damping coefficient*damping ratio
=265.91*0.7
=186.137N-s/m
Low-speed compression damping force
CF=DR*Knee speed
=186.137*50
=9,306.85N
Rear
DR=critical damping coefficient*damping ratio
=291.87*0.7
=204.31N-s/m
Low-speed compression damping force
CF=DR*Knee speed
=204.31*50
=10,215.5N
High-speed compression damping rate
Front
DR=critical damping coefficient*damping ratio
=311.76*0.2
=62.352N-s/m
High-speed compression damping force
CF=DR*max speed
=62.352*500
=31,176N
Rear
DR=critical damping coefficient*damping ratio
=259.23*0.2
=51.85N-s/m
High-speed compression damping force
CF=DR*Knee speed
=51.85*500
=25,925N
Low speed rebound damping rate
Front
DR=low compression damping rate *R/C
=3*186.137
=558.4N-s/m
Low-speed rebound damping force
RF=3*9,306.85
=27,920.55N
Rear
DR=low compression damping rate *R/C
=3*204.31
=612.93N-s/m
Low-speed rebound damping force
RF=3*10,215.5
=30,646.5N
High speed rebound damping rate
Front
DR=High compression damping rate *R/C
=3*62.352
=187.056N-s/m
High-speed rebound damping force
RF=3*31,176
=93,528N
Rear
DR=low compression damping rate *R/C
=3*51.85
=155.55N-s/m
High-speed rebound damping force
RF=3*25,925
=77,775N
2.