There once was a post-doc named Dave,Who ran OpenSees in his cave.Non-convergence, 'bout to miss dinner,He switched the algorithm to 'Linear'.Just think of all the trouble he saved. Although I changed the name and circumstances to protect the guilty, I have known more than one person who, when faced with convergence problems in OpenSees, decided … Continue reading Algorithmic Limerick
Tag: Algorithm
Non-Convergence Does Not Mean OpenSees Crashed
I once had the following conversation with a concerned user (CU) of OpenSees: CU: "I was running a response history analysis, then all of a sudden OpenSees crashed."PD: "Really, it crashed? Did you get the blue screen of death?"CU: "No. The analysis stopped and I saw 'Failed to converge'. It crashed."PD: "Oh, I see. What … Continue reading Non-Convergence Does Not Mean OpenSees Crashed
Be Careful with Modal Damping
Modal damping is kind of the it-spell in the dark art that is modeling viscous damping in structures. Although modal damping is pretty straightforward, you should be aware of an important aspect of its implementation in OpenSees. The issue is that OpenSees assembles the dynamic tangent in to the matrix storage scheme you choose via … Continue reading Be Careful with Modal Damping
