close all; clear
Fs=16; % Sampling frequency
a1=1; % Linear angular frequency squared f0=1/2/pi=0.16
a3=10; % Cubic nonlinear stiffness
a5=0.0; % Nonlinear stiffness
b1=0.05; % Linear damping
b2=0; % Nonlinear damping
x0=1e0; % Initial velocity
sim(‘s19’, 2e2); % Simulate a Simulink model
figure(1)
plot(y);
grid on
xlabel(‘Points, s’); ylabel(‘Displacement’);
title([‘Free vibration, a1=’ num2str(a1) ‘, b1=’ num2str(b1)]);