Vibration
The suspension system of a car traveling on a bumpy road has a stiffness of and the effective mass of the car on the suspension is m=750kg. The road bumps can be considered to be periodic half- sine waves as indicated in Figure. Determine the displacement response of the car. Assume the damping of the system to be negligible.
: The Fourier series representation of the bumpy road, y(t), is given by
y(t)=\frac{1}{\pi}+\frac{1}{2}sin~2\pi t-\frac{2}{\pi}{\frac{cos~4\pi t}{1(3)}+\frac{cos~8\pi t}{3(5)}+\frac{cos~12\pi t}{5(7)}+\cdot\cdot\cdot}
x(t)
t(time)
7777
J_{f}
m
(20 marks)
8^{k}
y(t)
hann
Sample Answer
Analyzing the Car’s Displacement Response
The problem describes a car traveling on a bumpy road modeled as a half-sine wave. We need to determine the car’s displacement response, considering the suspension system’s stiffness (k) and the car’s effective mass (m), assuming negligible damping.
The provided information includes the Fourier series representation of the road bump (y(t)). We can leverage this to find the displacement response (x(t)) of the car.
Here’s how to approach this problem:
1. Newton’s Second Law:
We can apply Newton’s second law (F = ma) to the car’s vertical motion. Here, F represents the force exerted by the suspension system, m is the car’s effective mass, and a is the car’s acceleration (second derivative of its displacement).