I read it like that:
(**T is the transpose)
Let's call M the mass matrix and N the modal mass matrix. Then
X**T*M*X=N. If X (matrix of eigenvectors) is normalized with respect to
M, N is I (unity) so it just mean that X**T*M*X=I. That is what octave
and matlab give you.
For this to be true. x**
Dear Fahreddın,
I think, the norm of the eigenvectors corresponds to some generic
amplitude. But that is something you cannot extract from the solution of
the eigenvalue problem but it depends on the initial deflection or
velocities.
So I think you should be able to use the normalized values just
