Calculate mass matrix

[Jriera]

Are there any instructions to obtain the mass matrix of a structure?

Thank you.

[dgale]

I have the same problem.

In the OpenSees manual is written the following:

------------MANUAL--------------
printA <-file $fileName>

will print the contents of a FullGeneral system that the integrator creates to the screen or a file if the -file option is used. If using a static integrator, the resulting matrix is the stiffness matrix. If a transient integrator, it will be some combination of mass and stiffness matrices
------------------------------------

But, what kind of combination is?

Thanks in advance
David

[yinghaozhao]

have you solved the problem now?
I take several trial but still don't know what is the combinantion of the " mass and stiffness matrices"

could someone give us a solution?

thanks
Yinghao

[selimgunay]

If you use the transient integrator "Explicit Newmark" with zero damping, the output of the printA command will be the mass matrix

[dgale]

Thanks Silimgunay!
And what about Force vector?, is there any implemented function to obtain it? like printA for K and M

[selimgunay]

As far as I know there is not. You can obtain it by multiplying K with the displacements when you use consistent dof in K and the displacement