comment on the multiple region command for rayleigh damping

[AbRiahi]

Dear all
I have a question about using multiple region command for rayleigh damping. I have studied the following Wiki example:
http://opensees.berkeley.edu/wiki/index ... es_and_RBS
In the above example the rayleigh damping is defined as the following:
region 4 -eleRange 111 213 rayleigh 0.0 0.0 $a1_mod 0.0; # assign stiffness proportional damping to frame beams & columns w/ n modifications
region 5 -eleRange 2121 2132 rayleigh 0.0 0.0 $a1 0.0; # assign stiffness proportional damping to frame beams & columns w/out n modifications
rayleigh $a0 0.0 0.0 0.0;
But I think that the way that the damping is defined is not appropriate. I mean that I think that the last rayleigh command will supressed all the previous ones. For example, one can simply change the values of $a1 and $a1 and notice that the results are unchanged.
I should also mention that by running the files(after downloading) I obtained different results for the dynamic analysis case compared to the example results.
I want to know that am I correct about this comment? How to get the example results in the dynamic analysis case? and how to define rayleigh command for two independent sets of nodes and elements?

[vesna]

yes, you are right. the last rayleigh command overwrites the regions.

to define damping for two independent sets of nodes and elements use "region" command.

with regard to dynamic analysis results try contacting the author of the example.