natural frequencies

Find a text on the application of the finite element method to modal analysis. My classes were many years ago, but as I remember it involves calculating the eigenvalues.

Need a mass matrix as well.

Before delving into FEM based modal I would suggest doing some basic work in SDOF & 2DOF systems using classical dynamic analysis.

The extrapolate to MDOF.

I'm away form my books & its been a LONG time & since I learned my dynamics / modal I cannot remember if Clough & Penzien covers this but if it does it will do a good job.

Are you thinking mechanical engineering applications or civil?

lighting columns, as in street lighting.

Why bother with FEM? Use classical (hand calcs) or use a FEM package that does modal for you.

No need to reinvent the wheel unless this is an academic exercise

cheers Bob

Point is, I need to do it all in PHP (I know....it's not the optimal choice for speed, but it's the optimal choice when trying to host with a commercial hoster a site that does numeric stuff). So I need to 'reinvent' matrix methods in PHP.

Dear erik:

PHP as in:

Since Perl is also free, could you not use Perl? This has already been done.

David A. Smith

who ? where ?

Deat erik:

David A. Smith