Seismosoft | Earthquake Engineering Solutions

Unfortunately, SeismoStruct 2020 does not feature a nonlinear slab element. What you could do is to use the beam section types (rcars or rcts sections) with a small depth to simulate the slab.
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No, the localisation issues are related to all fibre models.
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There are several posts in the forum regarding the convergence issues and how to solver them. Note that there is also a section in the program manual on what to do when one comes across specific divergence messages.
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There are several publications on the localisation issues in fibre modelling.
Please refer to these papers.
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The results are by no means 'very different'. The response of the two models is similar, within acceptable limits, e.g. the difference in the yield strength of the models is approximately 6%. The main difference in the models is the fact that in the infrmFB model that 10% strain level (where fractur...

This is strange. Can you please send the two files to support@seismosoft.com, so that we check the models?
Thanks.

If you model the joint with a link element, the energy dissipated is the area below the force-deformation curve. You may find several beam-column joint examples in the SeismoStruct verification report. Note that the corresponding SeismoStruct files are available from the program menu. Seismosoft Sup...

This is not reasonable. Are you sure that all the other parameters are the same? How many integration sections are you using with the infrmFB element type? Can you change the element type using the default parameters in each case and see if you get the similar results?
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Hello Michal,
Although I am not an expert on the field, I am not aware of any indirect method to calculate the energy dissipated only due to Rayleigh damping.
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Note that for the default infrmFB and infrmFBPH parameters, the results should not be very different. However, if you make significant changes to the plastic hinge length, the differences are expected to be high, as huffte very correctly pointed out.
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