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Hi all, I ve noticed in a couple of reference examples, there is the tendency to avoid using tangent stiffness proportional damping in zero length elements with non-linear hysteretic behavior, and apply the stiffness proportional at elastic members only. Why is that the case? I would say using the i...

if I were u, i would check the forces from the disp control analysis, because it is not easy to say how "small" your loads in the load controlled analysis are.

What do you mean exactly?
Would you expect that the yielding force is changing depending on the external load you apply?

Yielding force is capacity. It depends on the material property and geometry of the elements.

there is no way you can follow the same load-path with the load control curve, especially if u have softness. If you think about it, you would need to reduce your force to go beyond the peak point. it is the limitation of the load-controlled analysis. you are kinda applying a force in a system which...

if u go for a fast hand calc, would u agree that around 600*0.1*F is close to the end of the linear stage? in that case it means you need small step around there, because the change of stiffness is quite strong (sharp corner). how does ur disp control curve look like? is it going into softening? or ...

You kind of already now what the yielding force is of your model. So you know up to where you are in linear stage, right?

If it is linear stage, you should not have iteration at all. Should be quite fast. Try with a large step, what kind of error do you get?

Hi there, In my case it is always a trial-and-error procedure. It really depends on the non linearity of the curves. Often, you start with a large one, and if does not converge, you start reducing it gradually. By the way, if you want to get the full curve, you'd better use displacement control I wo...

fmk, i saw you wrote the source code for rigidLink. Would you expert issues in combination with the zero length rotational spring (and consequently equalDOF)? I am asking also cos in GSA for instance that would not even run. In fact, i model it in GSA, try to export into TCL, but doesnt work. Thanks...

selimgunay wrote: > Instead of the rigidLink constraint, why don't you model the beam itself > with a large E and I. I think it will be less problematic that way. Thanks for your reply. I have started having convergence issue I did not have before. The eigen analysis is quite poor as well. the domin...

dasgovind wrote: > How to calculate mass proportional and stiffness proportional damping. ? > And what is the role of eigen analysis. ? The rayleigh damping is a way to construct the damping matrix in a classical formulation. It is a viscous damping that is proportional to a linear combination of ma...

Hi all, I am modelling an equivalent frame. I've got elastic columns with rotational springs at the 2 ends (zero lenght elements). The spandrel is rather deep, so I would need to a rigid link to connect the end of the column(pier) to the central line of the spandrel (sap2000 does something similar)....

fmk wrote:
> look at the command manual .. damping in zerolength turned off by default
>
> http://opensees.berkeley.edu/wiki/index ... th_Element

Thanks a lot!

I am performing some sanity checks for my bigger model, with an SDoF model (see code below). I am having some issues with the rayleigh damping. I am trying with different combinations: stiffness prop only, mass prop only, and both. The system seems to respond only to the mass proportional part. If t...

Hi all,

is anyone aware of a package for curve calibration, based on experimental data? something like an optimization algorithm, which provides the best fit of some raw data and output the parameters of a certain material model?

Cheers,

selimgunay wrote:
> I will send it to you within few days. Could you tell me your email
> address?

It is: giovanni1.milan@gmail.com

Thank you.