Reduced Modal Analyse - Extracting Eigenfrequencies and mode shapes

[semesterarbeit]

Hi,
I'm simulating a camshaft and I need the Systemmatrix (reduced!!!). For this I need the Mass and the Stiffnessmatrix.
I just need the eigenfrequencies between 0 and 50000.
For this I'm using the command Modopt,,0,50000
I also need the modeshapes to get the matrices with following equations:
M*x_dotdot + C*x = F(t)
then I transform
x(t)=Phi*q(t) (Phi is the modal matrix)
and I'll get
Phi'*M*Phi*q_dotdot + Phi'*C*Phi*q = Phi'*F(t)
this is
I*q_dotdot+Lambda*q=Phi'*F(t)
with I as the Unity Matrix and Lambda with the quadratic eigenfrequencies in its diagonal.
Then I can calculate this with matlab back and I'll get the matrices.
But for this I need the eigenfrequencies (0-50000Hz) and the modeshapes (or the modal matrix)

Greets