Eigenvector problem with complex conjugate eigenvalues

Hello, im solving here a viscous damping problem. As you can see det(A) is the equation that must be solved in order to obtain the eigenvalues of the problem. My issue is after having all 10 eigenvalues (20 with their conjugates) i do not know exactly how to make MATLAB calculate me the eigenvectors of the problem, given that im not using the 'eig' command.
M=[1 0 0 0 0 0 0 0 0 0;
0 1 0 0 0 0 0 0 0 0;
0 0 1 0 0 0 0 0 0 0;
0 0 0 1 0 0 0 0 0 0;
0 0 0 0 1 0 0 0 0 0;
0 0 0 0 0 2 0 0 0 0;
0 0 0 0 0 0 3 0 0 0;
0 0 0 0 0 0 0 3 0 0;
0 0 0 0 0 0 0 0 4 0;
0 0 0 0 0 0 0 0 0 1];
K=[1 -1 0 0 0 0 0 0 0 0;
-1 3 0 0 0 0 -2 0 0 0;
0 0 3 -1 0 0 0 -2 0 0;
0 0 -1 1 0 0 0 0 0 0;
0 0 0 0 1 -1 0 0 0 0;
0 0 0 0 -1 3 -2 0 0 0;
0 -2 0 0 0 -2 8 -4 0 0;
0 0 -2 0 0 0 -4 11 -5 0;
0 0 0 0 0 0 0 -5 10 -5;
0 0 0 0 0 0 0 0 -5 5];
F=[1 -1 0 0 0 0 0 0 0 0;
-1 2 0 0 0 0 -1 0 0 0;
0 0 0 0 0 0 0 0 0 0;
0 0 0 0 0 0 0 0 0 0;
0 0 0 0 0 0 0 0 0 0;
0 0 0 0 0 0 0 0 0 0;
0 -1 0 0 0 0 2 -1 0 0;
0 0 0 0 0 0 -1 1 0 0;
0 0 0 0 0 0 0 0 0 0;
0 0 0 0 0 0 0 0 0 0];
f=2/50;
m=8;
k=2000;
Mv=m*M;
Fv=f*F;
Kv=K*k;
syms s phi
A=s^2*Mv +s*Fv+ Kv;
r=det(A);
s=double(subs(solve(r)));
for i=1:20
A=s(i)^2*Mv +s(i)*Fv+ Kv;
eqn= A*phi==0;
Mod(i)=double(subs(solve(eqn,phi)));
end

 Accepted Answer

null(A) might help:
https://de.mathworks.com/help/matlab/ref/null.html
Best wishes
Torsten.

More Answers (0)

Categories

Find more on Linear Algebra in Help Center and File Exchange

Asked:

on 8 Apr 2017

Answered:

on 10 Apr 2017

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!