@ Mike Rife
Thanks for your kind response. I have tried using *SMAT to export the sparsed mass and stiffness matrix using the following command line:
From the command line, I also tried to use NOD2BCS to infer the nodal DOF. I tried to link the nodal DOF from the output files as follows:
In the figure above, I tried to get the DOFs associated with node 289. My initial understanding is that the left column in the bracket is the DOF with the boundary nodes (For example, each node has 6 DOFs. Hence for node 289, the DOFs should be 1728:1733. The column after the semicolon is the DOF for node 289 in the stiffness & mass matrices.
After this, I applied a 1N force at node 289 in the X direction and applied 1N force in the force_vector (same size as the stiffness matrix) at DOF 1705. But the results differ from ANSYS and the calculated displacement from the extracted stiffness matrix.
Can you tell me which is the correct understanding of the exported file? Or the command I used is wrong.