I work in the field of Finite Element Methods, specifically, developing algorithms to speed up the computational time in structural mechanics problems. Till now I have been developing my code in Octave/Fortran and testing out my algorithms on small/simple problems (number of degrees of freedom less than 1000). Now I want to test out the algorithms on relatively large problems (number of degrees of freedom > 10000). To implement my algorithms, I need access to the system matrices: Mass, tangent Stiffness, Damping matrices, so that I can construct my reduced order model.
I would like to know which opensource FEA software (e.g., Calculix, Elmer, Tahoe or any other software) allows easy access and exchange of such information.