2nd Order Analysis on 2D Braced Frames

Question

Hello, 
 
 I have included links to two models below. In one model, I can run 2nd order analysis just fine, but the other seems to have issues. the only difference of any substance is that the loading is much heavier in one model, but the sections are capable of carrying that load. Note that both models run totally fine first order. I have consulted a few other experienced users in my office and we are all at a loss. Any help you can offer is appreciated. 
 Let me know if I can be of any more assistance on this issue. You can reach me at six zero six, three zero nine, four one four seven. 
 
 https://aro365531713-my.sharepoint.com/:u:/g/personal/jnichols_fhce_com/EdSVek9GTy9JgqlgbIrF9gQB_6Yzkt-nh6LH4u3xeHEubg?e=hBdjaw 
 https://aro365531713-my.sharepoint.com/:u:/g/personal/jnichols_fhce_com/ETUlHBYZThZMh26RKAGCIdIB1NQVM6nel9ssmbQ4HLKFGw?e=NbhBwc

Seth Guthrie · Accepted Answer

Is it the "Generic" model giving you the problem? I found that the P-Delta analysis would work if I used the Modified Newton-Raphson method (Solver tab in the current version). I also set the Model DOF to 2D frame, though I don't think that mattered. Click F1 for help anywhere inside the analysis dialog to see more on the 2 methods.

Seth Guthrie · Answer

There could be a problem of columns spinning about their 1 axis. Fix the base vs RY to rule that out. Using tension-only members with P-Delta analysis is the other factor to contend with here. Finally, if you don't want a node at the cross of the X, turn off the option "Add intermediate nodes at member intersections" on the FEM tab. I don't usually recommend this for tension-only X braces.

2nd Order Analysis on 2D Braced Frames

Top Replies