6.14 Figure P6.14 shows a 1-DOF model of an automotive suspension system, where mass m is one-quarter of the vehicle's mass, and the stiffness and damper elements represent the suspension system. The displace- ment xin (t) is the position of the wheel/axle assembly, and it is considered to be the known input to the system. Displacement of mass m is measured from its static equilibrium position. The system parameters are m= 1100 kg, k = 65,000 N/m, and the damper force of the shock absorber is modeled by the nonlinear equation 4500: (in N) Vz? + 12 where 2 = j - n(t) is the relative velocity across the shock absorber (in m/s), and y = 0.2 m/s. Obtain the dynamic response using Simulink for a sinusoidal input xin(t) = 0.03 sin 12t (in m). The system is initially al rest. 1/4 vehicle mass m x Shock absorber Suspension system E Wheel/axle |