Seismosoft | Earthquake Engineering Solutions

According to all modern codes on Structural Assessment, the nonlinear analysis are conducted considering the mean, rather than the characteristic material values.
Seismosoft Support

The fact that you cannot achieve convergence does not mean that you should change the rigid diaphragms of the model to X+Y+Z+RX+RY+RZ. This will completely alter the structural behavior. If you believe that you do not have structural failure in your building, then the convergence problem seems to be...

1) The message regarding the zero diagonal items in the stiffness matrix is a warning message of the program to notify users about this potential problem. With zero diagonal elements in [K], it is relatively easy to get divergence problems. If you have calibrated your model and it runs without probl...

You might get a better insight of the connectivity of your model by running eigenvalue analysis. In this way you can confirm that the shear wall is well connected to the rest of the structural model.
Seismosoft Support

You probably need to refer to the original publications, where the curves are described in detail.
One other alternative is to carry out trial analyses with a simple SDOF oscillator, trying different values of the parameters and seeing how the curves are affected.
Seismosoft Support

Unfortunately, this is only possible for commercial users.
We have literally thousands of academic users and, being a small company, we cannot provide full support to all of them. Apologies.
Seismosoft Support

The IDA analyses stop if at one scaling factor divergence occurs. This is because the size of each analysis in terms of bytes should be constant for the program to read correctly the results from the output file. However, note that once you get divergence at a LF=0.6, then you will almost certainly ...

The divergence problems do not occur in the first two analyses because the IDA scaling factors and the loading is smaller. The elm_inv and elm_tol messages mean that the program cannot find internal convergence in the diverging elements. This is usually due to large deformations in those elements. Y...

Can you please send us the input file at support@seismosoft.com?
Thanks
Seismosoft Support

Although rare, this is not something very weird or unexpected. In the time-steps of large loading, when the structure is close to collapse, small changes in the details analysis can lead to convergence or divergence. If you make the convergence criteria more stringent such discrepancies should norma...