% Eigen-method for calculation of NFs & NMs of a 3-DOF mass-spring system
clc
clear
% Given data
n=3;
m1=1; m2=1; m3=1; % in kg
k1=10000; k2=10000; k3=10000; k4=10000; % in N/m
% Eigen-method
M=[m1 0 0; 0 m2 0; 0 0 m3];
K=[k1+k2 -k2 0; -k2 k2+k3 -k3; 0 -k3 k3+k4];
D=inv(M)*K;
[A lam]=eig(D);
for i=1:n
om(i)=sqrt(lam(i,i));
end
om
A
AF=[0 0 0; A; 0 0 0]
plot(AF)
zero=[0 0 0 0 0];
hold on
plot(zero)
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