I'm new to opensees and I was reading the example files to learn it. I'm having a problem in defining material properties.
I was checking a file named "Ex5.Frame2D.build.InelasticSection" and I saw this :
-----------------------------------------------------------------------------------------------------------
# define MATERIAL properties ----------------------------------------
set Fy [expr 6.0*$ksi]
set Es [expr 29000*$ksi]; # Steel Young's Modulus
set nu 0.3;
set Gs [expr $Es/2./[expr 1+$nu]]; # Torsional stiffness Modulus
# COLUMN section W27x114
set AgCol [expr 33.5*pow($in,2)]; # cross-sectional area
set IzCol [expr 4090.*pow($in,4)]; # moment of Inertia
set EICol [expr $Es*$IzCol]; # EI, for moment-curvature relationship
set EACol [expr $Es*$AgCol]; # EA, for axial-force-strain relationship
set MyCol [expr 2e4*$kip*$in]; # yield moment
set PhiYCol [expr 0.25e-3/$in]; # yield curvature
set PhiYCol [expr $MyCol/$EICol]; # yield curvature
set EIColCrack [expr $MyCol/$PhiYCol]; # cracked section inertia
set b 0.01 ; # strain-hardening ratio (ratio between post-yield tangent and initial elastic tangent)
uniaxialMaterial Steel01 $ColMatTagFlex $MyCol $EIColCrack $b; # bilinear behavior for flexure
uniaxialMaterial Elastic $ColMatTagAxial $EACol; # this is not used as a material, this is an axial-force-strain response
section Aggregator $ColSecTag $ColMatTagAxial P $ColMatTagFlex Mz; # combine axial and flexural behavior into one section (no P-M interaction here)
----------------------------------------------------------------------------------------------------------------
I wanted to know what is "Mycol" ? Is that like some particular number that I should find in tables?
Or I should calculate that? Cause when I try to calculate it I do like this:
F = ( M * y ) / Iz (stress in bending)
So :
Fy = ( My * y ) / Iz ( stress in yield point)
6 = ( My * (27.29/2)) / 4090 ( (27.29/2) is the half of the height of W27x114)
then
My = 1799 kip
Where am I doing wrong?
and if you also explain about PHiYcol= 0.25*10e-3 I whould be glad
