Question

Ride comfort mainly arise from vibrations of the car body.
a) Determine the two natural frequencies of the bounce motions of the sprung and unsprung masses.
(10 marks)
b) Calculate the amplitudes of the sprung and unsprung parts if the car travels at a speed of 45 km/h
over a road of a sinewave form with a wavelength of 8.45 and amplitude of 3.5 cm.
(10 marks)

Answer 1

car 21 m M22. sprung mass kg x m = unsprung mass Kz Spring stiffness Ksz stiffrens of suspension Stijvers due to wheel. wheel kwa kw TIT Now let FBD fi 1 1/2 1 M2 m In 3 f as we know spring force = Kre Now from the above diagrames, F = kg (yok) Damper fea cx generelly F2 = c [y-se Now Fz=Kw [x-ee)

m, sc, a Fitfz-f3 = kg Cy-2) +cCy -&)-ka (word) m₂ u = -F, -Fe 2 -Kg Cynne) -Cly-&) Equations cg Motions are. mire, a ks cyane) + c(j-x) - kw (nor) müz -kgly-u) -clji) Natural frequenca watend frequency un sprung man 9 of sprung mans Kg xkw ✓ M, (Istkw) (kst kn) 27 22 M2 Mz
hey your given data is incomplete to solve part b of your question , please provide sufficient data like stifness of springs and masses of sprung mass and unsprung mass

i have uploaded part a from where you can calaculate your natural frequencies and equation of motions also has written in the above solution

thankyou