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?