I spent few hours exploring load cases and load combination in Karamba. I read through manual and I could not understand it. I am just wondering if anybody could point me to a video or an example about karamba with load combination explanation. Appreciate your help.
there is no inbuilt method to create load combinations. You will need to set it up in your scipt using manual multiplication methods to be able to calculate Load combinations. We are hoping to include this in future releases.
I am using the OptiCrossSec component to optimize my structures.
However i was wondering if i can use the deflection constraint for only certain “loadcombinations” that are SLS and it woudl ignore ULS combination. For ULS combinations it would only determine utilization.
Is something like that possible?
at the moment (Karamba3D 1.3.1) this is not possible. It is however on my TODO-list for the next release.
I have a question, are there at the moment further outputs to complete load combinations?
Hi E M Vanderpas,
one can use the ‘LCFactor’-input of the ‘ModelView’-component to superimpose different load-cases with user specified load-factors.
Would there be an example available somewhere which shows the utilization of the ‘LCFactor’-input of the ‘ModelView’?
Would it work like the following:
- Each Load Case has its own load Case number
- In the LCFactor we feed the Load combination factors of a specific Load Combination (ULS for instance)
- In the LCIndex, we feed the number of the load cases numbers in the same order than the LCFactors
- The “all” option in the model viewer will show the superimposed Load cases (So the Load combination)
- All the following components following the Model view (Like Beam view or Shell view) will also provide the information accordint to the specified load combination?
Could you confirm that those are the propper steps?
the load-cases in Karamba3D 1.3.2. are indexed starting from zero. ‘LCFactor’ (or ‘R-Factors’ in version 1.3.2) expects a list of doubles whose order corresponds to the order of the load-cases.
‘LCIndex’ (or ‘ResCase’ in version 1.3.2.) is only there to supplement the load-case selection done via the ‘ModelView’-component’s drop-down.list.
In order to get the super-imposed results from components further downstream you need to set the selected load-case to ‘-1’.
Thanks for your answer. I have however few problems:
- I am using version 1.3.2 - Build 190709 but the “LCFactor” is called “RCFactor” and not “R-Factor” and same for “LCIndex”
- The “-1” selected load case works only for some components: Its does not work for “reaction forces” or “Nodal displacement” for instance
“1. Model of iteration #0: Index of load-case index is out of range. You provided -1 while there are only 11 load-cases defined. The load-case index is zero based.”
it almost looks like i am not using the latest release even though it is 1.3.2 Any idea on what is going on?
as it seems there is an bug in how these components handle the input of ‘-1’ as a load-case number. Sorry for the inconvenience!
I am currently working on the subject of load-case and result-superposition. I will give you notice when the bug is removed.
In the meantime you could scale and sum up the results for each load-case via a C#-component or a small Grasshopper definition.
okay, thanks for your answer, ill wait for your update then! i already create a tiny definition to superpose the results “by hand” which seems to be giving consistent results with the model viewer (Displacement and support reaction for instance)