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1. I suggest you refer to a text book or google "rayleigh damping": https://www.orcina.com/webhelp/OrcaFlex/Content/html/Rayleighdamping,Guidance.htm https://www.usbr.gov/ssle/damsafety/TechDev/DSOTechDev/DSO-07-03.pdf 2. It cannot, from reading the text book or above links you should understand why.

you can issue the eigen command any time you want .. if what you want is to change the rayleigh values after each analysis step you can put the calculations above inside an analysis loop that only does 1 step at a time .. thohj you might leave out the puts if in a loop as this will kill perforrmance...

create multiple load patterns, e.g. some for earthquake and some for wind, before the same analyze command.

the file contains the fluctuating values of the wind load in a specific direction. in a pattern you are providing reference loads. the actula load applied at a node at any time is equal to the load factor from the time series (in your case the load you want applied pecified in your file) multipled b...

1. it is the basic stiffness method. 2. the standard K matrix (assuming you are not trying to use the penalty method to enforce constraints) 3. those large values are there I presume to get some rigid constraint enforced. In reality the terms only need to be a few orders of mag larger than the coeff...

put the elements in different regionas and assign different damping values to the different regions

i.e. end of file should look like the following with the loadConst added:

analyze 1
puts "##### STAGE 1 - finished #####";

loadConst -time 0.0

pattern Plain 2 Linear { load 1 0 -1000 0 0 0 0 }

analyze 1
puts "##### STAGE 2 - finished #####";

here is another example in our git repo
https://github.com/OpenSees/OpenSees/bl ... ays/j1.tcl

you could try another modelbuilder provided just for testing material .. here is an example i used awhile back model UniaxialMaterialTest uniaxialMaterial Elastic 1 3000 uniaxialMaterial MinMax 2 1 -min -0.001 uniaxialMaterial MinMax 3 1 -max 0.001 uniaxialMaterial MinMax 4 1 -min -0.001 -max 0.001 ...

post the script so i can see how you are modeling the elements

checking this works

the results are different because the element is "CURRENTLY" (i.e I might change this) just printing forces based on end moments and element length .. the recorder is reporting element forces which are determined from basic forces transformed by the geometric transformation .. for your example you a...

create a load pattern with a single load on the node you wish to apply the load to .. the load actually applied during the transient analysis will be the value of the load at the node (the pseudo load) TIMES the load factor obtained from the time series.

these materials cause problems .. i have some newer materials for modeling walls .. you might even try forgetting the beam elements with these .. here is some code copied from an example put together by Dr. Petrone # Concrete # Parameters for the new concrete model set E [expr 36900e6*$Pa] ;#elastic...