About rayleigh damping

[cicilixiaoran]

Hello, does the below code indicate that betaKcomm will be updated in every time step? Is it that if the Kcurrent is choosed, then the tangent stiffness is used and both Kcurrent and coefficient are changed in every time step, if the KlastCommitt is choosed, then the stiffness of the last committed step is used and only the coefficient is changed in every time step.Thank you!

set xDamp 0.02;
set ok 0;
set controlTime [getTime];
while {$controlTime < $TmaxAnalysis && $ok == 0} {
set controlTime [getTime]
set ok [analyze 1 $DtAnalysis]
set lambda [eigen 1]; # eigenvalue mode 1
set omega [expr pow($lambda,0.5)];
set alphaM 0.; # M-prop. damping; D = alphaM*M
set betaKcurr 0.;
set betaKcomm [expr 2.*$xDamp/($omega)];
set betaKinit 0.;
rayleigh $alphaM $betaKcurr $betaKinit $betaKcomm;
if {$ok != 0} {
puts "Trying Newton with Initial Tangent .."
test NormDispIncr $Tol 1000 0
algorithm Newton -initial
set ok [analyze 1 $DtAnalysis]
test $testTypeDynamic $TolDynamic $maxNumIterDynamic 0
algorithm $algorithmTypeDynamic
}
if {$ok != 0} {
puts "Trying Broyden .."
algorithm Broyden 8
set ok [analyze 1 $DtAnalysis]
algorithm $algorithmTypeDynamic
}
if {$ok != 0} {
puts "Trying NewtonWithLineSearch .."
algorithm NewtonLineSearch .8
set ok [analyze 1 $DtAnalysis]
algorithm $algorithmTypeDynamic
}
}

[vesna]

Yes, based on your code betaKcomm will be updated for every time step.

I see there is a confusion with what Kcurrent means.
If the Kcurrent is chosen, the tangent stiffness is changed with each iteration for one time step and coefficient betaKcurr is changed once for one time step.
If the Kcomm is chosen, the tangent stiffness is changed once for one time step and coefficient betaKcomm is changed once for one time step.