I have done my final project using matlab, performing dynamic analysis on model structure with FEM model (truss and frame) and time history method from several books. and now I would like to compare between my matlab analysis and SACS.
I formulate my matlab basedon the book, time history analysis (dynamic response-eartquake) most structures are modeled in a simpler form.
I found a mismatch on the mass matrix used. In one reference to the time history that I use, the mass matrix itself is asked to form a diagonal mass matrix. While the dynamic model using finite element analysis , does not produce mass matrix in the form of diagonal (either lumped mass or consisten mass).
I am afraid that forcing the finite element method on the time history formula I find will ignore the non-diagonal mass matrix form. I have not found the reference theory used on SACS itself. It is possible to know the theory used in sacs (ex: time history and finite element) makes me easier to match the results of accuracy in matlab and sacs.Anybody can help me, where I can find the formulas that used on SACS about it?
You can refer to Section 4.2 of the Dynpac manual for commentary on mass matrix generation and reduction using either the lumped or consistent mass approaches. You may be trying to compare your mass matrix with the reduced mass matrix which may be the reason for the discrepancy.
Regards,
Geoff
Answer Verified By: Geoff McDonald
Thank you sir