Hi guys, I'm having some troubles with the uniaxialMaterial Bond_SP01. Actually I hav a model which is set in N mm sec and my task is to scale it in m kN sec but I'm having some problems which I couldn't solve despite my troubleshooting, so I was wondering if someone could help me.
In the original model, which is set in N mm sec, the uniaxialMaterial Bond is set with the following values:
uniaxialMaterial Bond_SP01 200 360.0 0.17560975609756097 540.0 6.146341463414633 0.40 1.0
so if I scale the model in m kN sec I should get the following values:
uniaxialMaterial Bond_SP01 200 360000.0 0.00017560975609756096 540000.0 0.0061463414634146335 0.40 1.0
but I got the message: "WARNING: For the Strain-Penetration Model: input values in ksi and in." I hope that doesn't mean I can't set the model in m kN because otherwise I'm doomed.
uniaxialMaterial Bond_SP01
Moderators: silvia, selimgunay, Moderators
Re: uniaxialMaterial Bond_SP01
Please read developer's website:
https://pantherfile.uwm.edu/jzhao/www/B ... _FAQs.html
How to define a Bond_SP01 uniaxial material model?
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Q: how can I calculate la? I used Eq.2 in the ACI paper to find la,min and I got 95 mm.
A: you currently need six parameters (Fy, Sy, Fu, Su, b, and Rc) to define the bond_SP01 material model in the latest version of OpenSees. The rest four parameters are reserved for later upgrades of the model.
Q: I use SI system throughout the modeling. But in your module, input system is in US system. Please suggest how I use your module?
A: The equations for bond_Sp01 uses the normalized slips, hence the unit has no effect on the shape of the model curves. You need six parameters (Fy, Sy, Fu, Su, b, and Rc) to define the bond_SP01 material model in the latest version of OpenSees. Among these parameters, factor b is initial harding ratio and Rc is pinching factor (both are unitless). The ultimate slip currently is set to be dependent on the yield slip. Hence, all you need to do is to obtain Sy the yield slip. The equation in the current ACI paper is in SI units as required by ACI, you would have to use Pa for fc' in the equation to get the correct Sy in mm. Some changes have been made to the equation such that the equations in Si units and English units can be converted using unit conversion. These equations will be included in the opensees manual and the ACI paper.
Q: This units thing is a mess!!!
A: use ksi for Fy and Fu in the model parameter. Use psi in the equation for Sy. The reason for have a different set of units in the equation for Sy is to have unit conversion correct and viable and Fy/square root of Fc' unitless in the equation.
https://pantherfile.uwm.edu/jzhao/www/B ... _FAQs.html
How to define a Bond_SP01 uniaxial material model?
go toTop
Q: how can I calculate la? I used Eq.2 in the ACI paper to find la,min and I got 95 mm.
A: you currently need six parameters (Fy, Sy, Fu, Su, b, and Rc) to define the bond_SP01 material model in the latest version of OpenSees. The rest four parameters are reserved for later upgrades of the model.
Q: I use SI system throughout the modeling. But in your module, input system is in US system. Please suggest how I use your module?
A: The equations for bond_Sp01 uses the normalized slips, hence the unit has no effect on the shape of the model curves. You need six parameters (Fy, Sy, Fu, Su, b, and Rc) to define the bond_SP01 material model in the latest version of OpenSees. Among these parameters, factor b is initial harding ratio and Rc is pinching factor (both are unitless). The ultimate slip currently is set to be dependent on the yield slip. Hence, all you need to do is to obtain Sy the yield slip. The equation in the current ACI paper is in SI units as required by ACI, you would have to use Pa for fc' in the equation to get the correct Sy in mm. Some changes have been made to the equation such that the equations in Si units and English units can be converted using unit conversion. These equations will be included in the opensees manual and the ACI paper.
Q: This units thing is a mess!!!
A: use ksi for Fy and Fu in the model parameter. Use psi in the equation for Sy. The reason for have a different set of units in the equation for Sy is to have unit conversion correct and viable and Fy/square root of Fc' unitless in the equation.
Mostafa Tazarv
Re: uniaxialMaterial Bond_SP01
Well, I have seen whoever made this model didn't use the equation reported in the Open Sees manual at page 47 to calculate sy (don't ask me why), instead he set in the model the elastic module of steel to a value of 205000 [MPa] and set the ultimate steel strength fy to a value of 360 [N/mm^2]. Finally he calculated sy as a ratio
"set sy [expr {$fy*100/$Es}]"
which if I’m not mistaken should be unitless.
So you suggest I simply use the values in ksi for fy and that shouldn't affect the simulation, I gonna try it!
"set sy [expr {$fy*100/$Es}]"
which if I’m not mistaken should be unitless.
So you suggest I simply use the values in ksi for fy and that shouldn't affect the simulation, I gonna try it!